Internet Research Task Force T. Li, Ed.
Internet-Draft Cisco Systems
Intended status: Informational August 17, 2010
Expires: February 18, 2011
Recommendation for a Routing Architecture
draft-irtf-rrg-recommendation-10
Abstract
It is commonly recognized that the Internet routing and addressing
architecture is facing challenges in scalability, multihoming, and
inter-domain traffic engineering. This document surveys many of the
proposals that were brought forward for discussion in this activity,
as well as some of the subsequent analysis.
Status of this Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1. Structure of This Document . . . . . . . . . . . . . . . . 6
1.2. Areas of Group Consensus . . . . . . . . . . . . . . . . . 6
1.3. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 7
2. Locator Identifier Separation Protocol (LISP) . . . . . . . . 8
2.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1.1. Key Idea . . . . . . . . . . . . . . . . . . . . . . . 9
2.1.2. Gains . . . . . . . . . . . . . . . . . . . . . . . . 9
2.1.3. Costs . . . . . . . . . . . . . . . . . . . . . . . . 10
2.1.4. References . . . . . . . . . . . . . . . . . . . . . . 10
2.2. Critique . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3. Rebuttal . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.4. Counterpoint . . . . . . . . . . . . . . . . . . . . . . . 12
3. Routing Architecture for the Next Generation Internet
(RANGI) . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.1.1. Key Idea . . . . . . . . . . . . . . . . . . . . . . . 12
3.1.2. Gains . . . . . . . . . . . . . . . . . . . . . . . . 13
3.1.3. Costs . . . . . . . . . . . . . . . . . . . . . . . . 13
3.1.4. References . . . . . . . . . . . . . . . . . . . . . . 14
3.2. Critique . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.3. Rebuttal . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.4. Counterpoint . . . . . . . . . . . . . . . . . . . . . . . 16
4. Internet Vastly Improved Plumbing (Ivip) . . . . . . . . . . . 16
4.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.1.1. Key Ideas . . . . . . . . . . . . . . . . . . . . . . 16
4.1.2. Extensions . . . . . . . . . . . . . . . . . . . . . . 17
4.1.2.1. TTR Mobility . . . . . . . . . . . . . . . . . . . 17
4.1.2.2. Modified Header Forwarding . . . . . . . . . . . . 18
4.1.3. Gains . . . . . . . . . . . . . . . . . . . . . . . . 18
4.1.4. Costs . . . . . . . . . . . . . . . . . . . . . . . . 19
4.1.5. References . . . . . . . . . . . . . . . . . . . . . . 19
4.2. Critique . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.3. Rebuttal . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.4. Counterpoint . . . . . . . . . . . . . . . . . . . . . . . 21
5. Hierarchical IPv4 Framework (hIPv4) . . . . . . . . . . . . . 21
5.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.1.1. Key Idea . . . . . . . . . . . . . . . . . . . . . . . 21
5.1.2. Gains . . . . . . . . . . . . . . . . . . . . . . . . 22
5.1.3. Costs And Issues . . . . . . . . . . . . . . . . . . . 23
5.1.4. References . . . . . . . . . . . . . . . . . . . . . . 24
5.2. Critique . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.3. Rebuttal . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.4. Counterpoint . . . . . . . . . . . . . . . . . . . . . . . 25
6. Name overlay (NOL) service for scalable Internet routing . . . 25
6.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 25
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6.1.1. Key Idea . . . . . . . . . . . . . . . . . . . . . . . 25
6.1.2. Gains . . . . . . . . . . . . . . . . . . . . . . . . 26
6.1.3. Costs . . . . . . . . . . . . . . . . . . . . . . . . 27
6.1.4. References . . . . . . . . . . . . . . . . . . . . . . 27
6.2. Critique . . . . . . . . . . . . . . . . . . . . . . . . . 27
6.3. Rebuttal . . . . . . . . . . . . . . . . . . . . . . . . . 28
6.4. Counterpoint . . . . . . . . . . . . . . . . . . . . . . . 29
7. Compact routing in locator identifier mapping system (CRM) . . 29
7.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 29
7.1.1. Key Idea . . . . . . . . . . . . . . . . . . . . . . . 29
7.1.2. Gains . . . . . . . . . . . . . . . . . . . . . . . . 30
7.1.3. Costs . . . . . . . . . . . . . . . . . . . . . . . . 30
7.1.4. References . . . . . . . . . . . . . . . . . . . . . . 30
7.2. Critique . . . . . . . . . . . . . . . . . . . . . . . . . 30
7.3. Rebuttal . . . . . . . . . . . . . . . . . . . . . . . . . 31
7.4. Counterpoint . . . . . . . . . . . . . . . . . . . . . . . 32
8. Layered mapping system (LMS) . . . . . . . . . . . . . . . . . 32
8.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 32
8.1.1. Key Ideas . . . . . . . . . . . . . . . . . . . . . . 32
8.1.2. Gains . . . . . . . . . . . . . . . . . . . . . . . . 32
8.1.3. Costs . . . . . . . . . . . . . . . . . . . . . . . . 33
8.1.4. References . . . . . . . . . . . . . . . . . . . . . . 33
8.2. Critique . . . . . . . . . . . . . . . . . . . . . . . . . 33
8.3. Rebuttal . . . . . . . . . . . . . . . . . . . . . . . . . 35
8.4. Counterpoint . . . . . . . . . . . . . . . . . . . . . . . 35
9. 2-phased mapping . . . . . . . . . . . . . . . . . . . . . . . 35
9.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 35
9.1.1. Considerations . . . . . . . . . . . . . . . . . . . . 35
9.1.2. Basics of a 2-phased mapping . . . . . . . . . . . . . 35
9.1.3. Gains . . . . . . . . . . . . . . . . . . . . . . . . 36
9.1.4. Summary . . . . . . . . . . . . . . . . . . . . . . . 36
9.1.5. References . . . . . . . . . . . . . . . . . . . . . . 36
9.2. Critique . . . . . . . . . . . . . . . . . . . . . . . . . 36
9.3. Rebuttal . . . . . . . . . . . . . . . . . . . . . . . . . 37
9.4. Counterpoint . . . . . . . . . . . . . . . . . . . . . . . 37
10. Global Locator, Local Locator, and Identifier Split
(GLI-Split) . . . . . . . . . . . . . . . . . . . . . . . . . 37
10.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 37
10.1.1. Key Idea . . . . . . . . . . . . . . . . . . . . . . . 37
10.1.2. Gains . . . . . . . . . . . . . . . . . . . . . . . . 37
10.1.3. Costs . . . . . . . . . . . . . . . . . . . . . . . . 38
10.1.4. References . . . . . . . . . . . . . . . . . . . . . . 38
10.2. Critique . . . . . . . . . . . . . . . . . . . . . . . . . 38
10.3. Rebuttal . . . . . . . . . . . . . . . . . . . . . . . . . 39
10.4. Counterpoint . . . . . . . . . . . . . . . . . . . . . . . 40
11. Tunneled Inter-domain Routing (TIDR) . . . . . . . . . . . . . 40
11.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 40
11.1.1. Key Idea . . . . . . . . . . . . . . . . . . . . . . . 40
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11.1.2. Gains . . . . . . . . . . . . . . . . . . . . . . . . 41
11.1.3. Costs . . . . . . . . . . . . . . . . . . . . . . . . 41
11.1.4. References . . . . . . . . . . . . . . . . . . . . . . 41
11.2. Critique . . . . . . . . . . . . . . . . . . . . . . . . . 42
11.3. Rebuttal . . . . . . . . . . . . . . . . . . . . . . . . . 43
11.4. Counterpoint . . . . . . . . . . . . . . . . . . . . . . . 43
12. Identifier-Locator Network Protocol (ILNP) . . . . . . . . . . 43
12.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 43
12.1.1. Key Ideas . . . . . . . . . . . . . . . . . . . . . . 43
12.1.2. Benefits . . . . . . . . . . . . . . . . . . . . . . . 43
12.1.3. Costs . . . . . . . . . . . . . . . . . . . . . . . . 45
12.1.4. References . . . . . . . . . . . . . . . . . . . . . . 45
12.2. Critique . . . . . . . . . . . . . . . . . . . . . . . . . 45
12.3. Rebuttal . . . . . . . . . . . . . . . . . . . . . . . . . 46
12.4. Counterpoint . . . . . . . . . . . . . . . . . . . . . . . 48
13. Enhanced Efficiency of Mapping Distribution Protocols in
Map-and-Encap Schemes (EEMDP) . . . . . . . . . . . . . . . . 48
13.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 48
13.1.1. Introduction . . . . . . . . . . . . . . . . . . . . . 48
13.1.2. Management of Mapping Distribution of Subprefixes
Spread Across Multiple ETRs . . . . . . . . . . . . . 49
13.1.3. Management of Mapping Distribution for Scenarios
with Hierarchy of ETRs and Multihoming . . . . . . . . 50
13.1.4. References . . . . . . . . . . . . . . . . . . . . . . 50
13.2. Critique . . . . . . . . . . . . . . . . . . . . . . . . . 51
13.3. Rebuttal . . . . . . . . . . . . . . . . . . . . . . . . . 52
13.4. Counterpoint . . . . . . . . . . . . . . . . . . . . . . . 53
14. Evolution . . . . . . . . . . . . . . . . . . . . . . . . . . 53
14.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 53
14.1.1. Need for Evolution . . . . . . . . . . . . . . . . . . 53
14.1.2. Relation to Other RRG Proposals . . . . . . . . . . . 53
14.1.3. Aggregation with Increasing Scopes . . . . . . . . . . 54
14.1.4. References . . . . . . . . . . . . . . . . . . . . . . 55
14.2. Critique . . . . . . . . . . . . . . . . . . . . . . . . . 55
14.3. Rebuttal . . . . . . . . . . . . . . . . . . . . . . . . . 57
14.4. Counterpoint . . . . . . . . . . . . . . . . . . . . . . . 57
15. Name-Based Sockets . . . . . . . . . . . . . . . . . . . . . . 57
15.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 57
15.1.1. References . . . . . . . . . . . . . . . . . . . . . . 59
15.2. Critique . . . . . . . . . . . . . . . . . . . . . . . . . 59
15.2.1. Deployment . . . . . . . . . . . . . . . . . . . . . . 59
15.2.2. Edge-networks . . . . . . . . . . . . . . . . . . . . 60
15.3. Rebuttal . . . . . . . . . . . . . . . . . . . . . . . . . 60
15.4. Counterpoint . . . . . . . . . . . . . . . . . . . . . . . 60
16. Routing and Addressing in Networks with Global Enterprise
Recursion (IRON-RANGER) . . . . . . . . . . . . . . . . . . . 60
16.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 60
16.1.1. Gains . . . . . . . . . . . . . . . . . . . . . . . . 61
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16.1.2. Costs . . . . . . . . . . . . . . . . . . . . . . . . 61
16.1.3. References . . . . . . . . . . . . . . . . . . . . . . 62
16.2. Critique . . . . . . . . . . . . . . . . . . . . . . . . . 62
16.3. Rebuttal . . . . . . . . . . . . . . . . . . . . . . . . . 62
16.4. Counterpoint . . . . . . . . . . . . . . . . . . . . . . . 64
17. Recommendation . . . . . . . . . . . . . . . . . . . . . . . . 64
17.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 64
17.2. Recommendation to the IETF . . . . . . . . . . . . . . . . 65
17.3. Rationale . . . . . . . . . . . . . . . . . . . . . . . . 66
18. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 66
19. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 66
20. Security Considerations . . . . . . . . . . . . . . . . . . . 67
21. References . . . . . . . . . . . . . . . . . . . . . . . . . . 67
21.1. Normative References . . . . . . . . . . . . . . . . . . . 67
21.2. Informative References . . . . . . . . . . . . . . . . . . 67
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 72
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1. Introduction
It is commonly recognized that the Internet routing and addressing
architecture is facing challenges in scalability, multihoming, and
inter-domain traffic engineering. The problem being addressed has
been documented in [I-D.narten-radir-problem-statement], and the
design goals that we have discussed can be found in
[I-D.irtf-rrg-design-goals].
This document surveys many of the proposals that were brought forward
for discussion in this activity. For some of the proposals, this
document also includes additional analysis showing some of the
concerns with specific proposals, and how some of those concerns may
be addressed. Readers are cautioned not to draw any conclusions
about the degree of interest or endorsement by the Routing Research
Group (RRG) from the presence of any proposals in this document, or
the amount of analysis devoted to specific proposals.
1.1. Structure of This Document
This document describes a number of the different possible approaches
that could be taken in a new routing architecture, as well as a
summary of the current thinking of the overall group regarding each
approach.
This document also includes the recommendation from the research
group to the IETF. The group did not reach consensus on this
recommendation, thus the recommendation reflects the decision of the
co-chairs. The group did reach consensus that the overall document
should be published.
1.2. Areas of Group Consensus
The group was also able to reach broad and clear consensus on some
terminology and several important technical points. For the sake of
posterity, these are recorded here:
1. A "node" is either a host or a router.
2. A "router" is any device that forwards packets at the Network
Layer (e.g. IPv4, IPv6) of the Internet Architecture.
3. A "host" is a device that can send/receive packets to/from the
network, but does not forward packets.
4. A "bridge" is a device that forwards packets at the Link Layer
(e.g. Ethernet) of the Internet Architecture. An Ethernet
switch or Ethernet hub are examples of bridges.
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5. An "address" is an object that combines aspects of identity with
topological location. IPv4 and IPv6 addresses are current
examples.
6. A "locator" is a structured topology-dependent name that is not
used for node identification, and is not a path. Two related
meanings are current, depending on the class of things being
named:
1. The topology-dependent name of a node's interface.
2. The topology-dependent name of a single subnetwork OR
topology-dependent name of a group of related subnetworks
that share a single aggregate. An IP routing prefix is a
current example of this last.
7. An "identifier" is a topology-independent name for a logical
node. Depending upon instantiation, a "logical node" might be a
single physical device, a cluster of devices acting as a single
node, or a single virtual partition of a single physical device.
An OSI End System Identifier (ESID) is an example of an
identifier. A Fully-Qualified Domain Name that precisely names
one logical node is another example. (Note well that not all
FQDNs meet this definition.)
8. Various other names (i.e. other than addresses, locators, or
identifiers), each of which has the sole purpose of identifying
a component of a logical system or physical device, might exist
at various protocol layers in the Internet Architecture.
9. The Research Group has rough consensus that separating identity
from location is desirable and technically feasible. However,
the Research Group does NOT have consensus on the best
engineering approach to such an identity/location split.
10. The Research Group has consensus that the Internet needs to
support multihoming in a manner that scales well and does not
have prohibitive costs.
11. Any IETF solution to Internet scaling has to not only support
multihoming, but address the real-world constraints of the end
customers (large and small).
1.3. Abbreviations
This section lists some of the most common abbreviations used in the
remainder of this document.
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DFZ Default-Free Zone
EID Endpoint IDentifer: The precise definition varies depending on
the proposal.
ETR Egress Tunnel Router: In a system that tunnels traffic across
the existing infrastructure by encapsulating it, the device close
to the actual ultimate destination that decapsulates the traffic
before forwarding it to the ultimate destination.
FIB Forwarding Information Base: The forwarding table, used in the
data plane of routers to select the next hop for each packet.
ITR Ingress Tunnel Router: In a system that tunnels traffic across
the existing infrastructure by encapsulating it, the device close
to the actual original source that encapsulates the traffic before
using the tunnel to send it to the appropriate ETR.
PA Provider Aggregatable: Address space that can be aggregated as
part of a service provider's routing advertisements.
PI Provider Independent: Address space assigned by an Internet
registry independent of any service provider.
PMTUD Path Maximum Transmission Unit Discovery: The process or
mechanism that determines the largest packet that can be sent
between a given source and destination with being either i)
fragmented (IPv4 only), or ii) discarded (if not fragmentable)
because it is too large to be sent down one link in the path from
the source to the destination.
RIB Routing Information Base. The routing table, used in the
control plane of routers to exchange routing information and
construct the FIB.
RLOC Routing LOCator: The precise definition varies depending on the
proposal.
xTR Tunnel Router: In some systems, the term used to describe a
device which can function as both an ITR and an ETR.
2. Locator Identifier Separation Protocol (LISP)
2.1. Summary
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2.1.1. Key Idea
Implements a locator-identifier separation mechanism using
encapsulation between routers at the "edge" of the Internet. Such a
separation allows topological aggregation of the routable addresses
(locators) while providing stable and portable numbering of end
systems (identifiers).
2.1.2. Gains
o topological aggregation of locator space (RLOCs) used for routing,
which greatly reduces both the overall size and the "churn rate"
of the information needed to operate the Internet global routing
system
o separate identifier space (EIDs) for end-systems, effectively
allowing "PI for all" (no renumbering cost for connectivity
changes) without adding state to the global routing system
o improved traffic engineering capabilities that explicitly do not
add state to the global routing system and whose deployment will
allow active removal of the more-specific state that is currently
used
o no changes required to end systems
o no changes to Internet "core" routers
o minimal and straightforward changes to "edge" routers
o day-one advantages for early adopters
o defined router-to-router protocol
o defined database mapping system
o defined deployment plan
o defined interoperability/interworking mechanisms
o defined scalable end-host mobility mechanisms
o prototype implementation already exists and undergoing testing
o production implementations in progress
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2.1.3. Costs
o mapping system infrastructure (map servers, map resolvers, ALT
routers) (new potential business opportunity)
o Interworking infrastructure (proxy ITRs) (new potential business
opportunity)
o overhead for determining/maintaining locator/path liveness (common
issue for all id/loc separation proposals)
2.1.4. References
[I-D.ietf-lisp] [I-D.ietf-lisp-alt] [I-D.ietf-lisp-ms]
[I-D.ietf-lisp-interworking] [I-D.meyer-lisp-mn]
[I-D.farinacci-lisp-lig] [I-D.meyer-loc-id-implications]
2.2. Critique
LISP-ALT distributes mapping information to ITRs via (optional,
local, potentially caching) Map Resolvers and with globally
distributed query servers: ETRs and optional Map Servers (MS).
A fundamental problem with any global query server network is that
the frequently long paths and greater risk of packet loss may cause
ITRs to drop or significantly delay the initial packets of many new
sessions. ITRs drop the packet(s) they have no mapping for. After
the mapping arrives, the ITR waits for a resent packet and will
tunnel that packet correctly. These "initial packet delays" reduce
performance and so create a major barrier to voluntary adoption on
wide enough basis to solve the routing scaling problem.
ALT's delays are compounded by its structure being "aggressively
aggregated", without regard to the geographic location of the
routers. Tunnels between ALT routers will often span
intercontinental distances and traverse many Internet routers.
The many levels to which a query typically ascends in the ALT
hierarchy before descending towards its destination will often
involve excessively long geographic paths and so worsen initial
packet delays.
No solution has been proposed for these problems or for the
contradiction between the need for high aggregation while making the
ALT structure robust against single points of failure.
LISP's ITRs multihoming service restoration depends on them
determining reachability of end-user networks via two or more ETRs.
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Large numbers of ITRs doing this is inefficient and may overburden
ETRs.
Testing reachability of the ETRs is complex and costly - and
insufficient. ITRs cannot test network reachability via each ETR,
since the ITRs have no address of a device in that network. So ETRs
must report network un-reachability to ITRs.
LISP involves complex communication between ITRs and ETRs, with UDP
and 64-bit LISP headers in all traffic packets.
The advantage of LISP+ALT is that its ability to handle billions of
EIDs is not constrained by the need to transmit or store the mapping
to any one location. Such numbers, beyond a few tens of millions of
EIDs, will only result if the system is used for Mobility. Yet the
concerns just mentioned about ALT's structure arise from the millions
of ETRs which would be needed just for non-mobile networks.
In LISP's mobility approach each Mobile Node (MN) needs an RLOC
address to be its own ETR, meaning the MN cannot be behind NAT.
Mapping changes must be sent instantly to all relevant ITRs every
time the MN gets a new address - which LISP cannot achieve.
In order to enforce ISP filtering of incoming packets by source
address, LISP ITRs would have to implement the same filtering on each
decapsulated packet. This may be prohibitively expensive.
LISP monolithically integrates multihoming failure detection and
restoration decision-making processes into the Core-Edge Separation
(CES) scheme itself. End-user networks must rely on the necessarily
limited capabilities which are built into every ITR.
LISP-ALT may be able to solve the routing scaling problem, but
alternative approaches would be superior because they eliminate the
initial packet delay problem and give end-user networks real-time
control over ITR tunneling.
2.3. Rebuttal
Initial-packet loss/delays turn out not to be a deep issue.
Mechanisms for interoperation with the legacy part of the network are
needed in any viably deployable design, and LISP has such mechanisms.
If needed, initial packets can be sent via those legacy mechanisms
until the ITR has a mapping. (Field experience has shown that the
caches on those interoperation devices are guaranteed to be
populated, as 'crackers' doing address-space sweeps periodically send
packets to every available mapping.)
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On ALT issues, it is not at all mandatory that ALT be the mapping
system used in the long term. LISP has a standardized mapping system
interface, in part to allow reasonably smooth deployment of whatever
new mapping system(s) experience might show are required. At least
one other mapping system (LISP-TREE), which avoids ALT's problems
(such as query load concentration at high-level nodes), has already
been laid out and extensively simulated. Exactly what mixture of
mapping system(s) is optimal is not really answerable without more
extensive experience, but LISP is designed to allow evolutionary
changes to other mapping system(s).
As far as ETR reachability goes, a potential problem to which there
is a solution which has an adequate level of efficiency, complexity
and robustness is not really a problem. LISP has a number of
overlapping mechanisms which it is believed will provide adequate
reachability detection (along the three axes above), and in field
testing to date, they have behaved as expected.
Operation of LISP devices behind a NAT has already been demonstrated.
A number of mechanisms to update correspondent nodes when a mapping
is updated have been designed (some are already in use).
2.4. Counterpoint
No counterpoint was submitted for this proposal.
3. Routing Architecture for the Next Generation Internet (RANGI)
3.1. Summary
3.1.1. Key Idea
Similar to Host Identity Protocol (HIP) [RFC4423], RANGI introduces a
host identifier layer between the network layer and the transport
layer, and the transport-layer associations (i.e., TCP connections)
are no longer bound to IP addresses, but to host identifiers. The
major difference from HIP is that the host identifier in RANGI is a
128-bit hierarchical and cryptographic identifier which has
organizational structure. As a result, the corresponding ID->locator
mapping system for such identifiers has a reasonable business model
and clear trust boundaries. In addition, RANGI uses IPv4-embedded
IPv6 addresses as locators. The Locator Domain Identifier (LD ID)
(i.e., the leftmost 96 bits) of this locator is a provider-assigned
/96 IPv6 prefix, while the last four octets of this locator is a
local IPv4 address (either public or private). This special locator
could be used to realize 6over4 automatic tunneling (borrowing ideas
from ISATAP [RFC5214]), which will reduce the deployment cost of this
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new routing architecture. Within RANGI, the mappings from FQDN to
host identifiers are stored in the DNS system, while the mappings
from host identifiers to locators are stored in a distributed id/
locator mapping system (e.g., a hierarchical Distributed Hash Table
(DHT) system, or a reverse DNS system).
3.1.2. Gains
RANGI achieves almost all of the goals set forth by RRG as follows:
1. Routing Scalability: Scalability is achieved by decoupling
identifiers from locators.
2. Traffic Engineering: Hosts located in a multihomed site can
suggest the upstream ISP for outbound and inbound traffic, while
the first-hop Locator Domain Border Router (LDBR) (i.e., site
border router) has the final decision on the upstream ISP
selection.
3. Mobility and Multihoming: Sessions will not be interrupted due to
locator change in cases of mobility or multihoming.
4. Simplified Renumbering: When changing providers, the local IPv4
addresses of the site do not need to change. Hence the internal
routers within the site don't need renumbering.
5. Decoupling Location and Identifier: Obvious.
6. Routing Stability: Since the locators are topologically
aggregatable and the internal topology within the LD will not be
disclosed outside, routing stability could be improved greatly.
7. Routing Security: RANGI reuses the current routing system and
does not introduce any new security risks into the routing
system.
8. Incremental Deployability: RANGI allows an easy transition from
IPv4 networks to IPv6 networks. In addition, RANGI proxy allows
RANGI-aware hosts to communicate to legacy IPv4 or IPv6 hosts,
and vice-versa.
3.1.3. Costs
1. A host change is required.
2. The first-hop LDBR change is required to support site-controlled
traffic-engineering capability.
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3. The ID->Locator mapping system is a new infrastructure to be
deployed.
4. RANGI proxy needs to be deployed for communication between RANGI-
aware hosts and legacy hosts.
3.1.4. References
[RFC3007] [RFC4423] [I-D.xu-rangi] [I-D.xu-rangi-proxy] [RANGI]
3.2. Critique
RANGI is an ID/locator split protocol that, like HIP, places a
cryptographically signed ID between the network layer (IPv6) and
transport. Unlike the HIP ID, the RANGI ID has a hierarchical
structure that allows it to support ID->locator lookups. This
hierarchical structure addresses two weaknesses of the flat HIP ID:
the difficulty of doing the ID->locator lookup, and the
administrative scalability of doing firewall filtering on flat IDs.
The usage of this hierarchy is overloaded: it serves to make the ID
unique, to drive the lookup process, and possibly other things like
firewall filtering. More thought is needed as to what constitutes
these levels with respect to these various roles.
The RANGI draft suggests FQDN->ID lookup through DNS, and separately
an ID->locator lookup which may be DNS or may be something else (a
hierarchy of DHTs). It would be more efficient if the FQDN lookup
produces both ID and locators (as does ILNP). Probably DNS alone is
sufficient for the ID->locator lookup since individual DNS servers
can hold very large numbers of mappings.
RANGI provides strong sender identification, but at the cost of
computing crypto. Many hosts (public web servers) may prefer to
forgo the crypto at the expense of losing some functionality
(receiver mobility or dynamic multihome load balance). While RANGI
doesn't require that the receiver validate the sender, it may be good
to have a mechanism whereby the receiver can signal to the sender
that it is not validating, so that the sender can avoid locator
changes.
Architecturally there are many advantages to putting the mapping
function at the end host (versus at the edge). This simplifies the
neighbor aliveness and delayed first packet problems, and avoids
stateful middleboxes. Unfortunately, the early-adopter incentive for
host upgrade may not be adequate (HIP's lack of uptake being an
example).
RANGI does not have an explicit solution for the mobility race
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condition (there is no mention of a home-agent like device).
However, host-to-host notification combined with fallback on the
ID->locators lookup (assuming adequate dynamic update of the lookup
system) may be good enough for the vast majority of mobility
situations.
RANGI uses proxies to deal with both legacy IPv6 and IPv4 sites.
RANGI proxies have no mechanisms to deal with the edge-to-edge
aliveness problem. The edge-to-edge proxy approach dirties-up an
otherwise clean end-to-end model.
RANGI exploits existing IPv6 transition technologies (ISATAP and
softwire). These transition technologies are in any event being
pursued outside of RRG and do not need to be specified in RANGI
drafts per se. RANGI only needs to address how it interoperates with
IPv4 and legacy IPv6, which through proxies it appears to do
adequately well.
3.3. Rebuttal
The reason why the ID->Locator lookup is separated from the FQDN->ID
lookup is: 1) not all applications are tied to FQDNs, and 2) it seems
unnecessary to require all devices to possess a FQDN of their own.
Basically RANGI uses DNS to realize the ID->Locator mapping system.
If there are too many entries to be maintained by the authoritative
servers of a given Administrative Domain (AD), Distribute Hash Table
(DHT) technology can be used to make these authoritative servers
scale better, e.g., the mappings maintained by a given AD will be
distributed among a group of authoritative servers in a DHT fashion.
As a result, the robustness feature of DHT is inherited naturally
into the ID->Locator mapping system. Meanwhile, there is no trust
issue since each AD authority runs its own DHT ring which maintains
only the mappings for those identifiers that are administrated by
that AD authority.
For host mobility, if communicating entities are RANGI nodes, the
mobile node will notify the correspondent node of its new locator
once its locator changes due to a mobility or re-homing event.
Meanwhile, it should also update its locator information in the
ID->Locator mapping system in a timely fashion by using the Secure
DNS Dynamic Update mechanism defined in [RFC3007]. In case of
simultaneous mobility, at least one of the nodes has to resort to the
ID->Locator mapping system for resolving the correspondent node's new
locator so as to continue their communication. If the correspondent
node is a legacy host, Transit Proxies, which play a similar function
to the home-agents in Mobile IP, will relay the packets between the
communicating parties.
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RANGI uses proxies (e.g., Site Proxy and Transit Proxy) to deal with
both legacy IPv6 and IPv4 sites. Since proxies function as RANGI
hosts, they can handle Locator Update Notification messages sent from
remote RANGI hosts (or even from remote RANGI proxies) correctly.
Hence there is no edge-to-edge aliveness problem. Details will be
specified in the latter version of RANGI-PROXY.
The intention behind RANGI using IPv4-embedded IPv6 addresses as
locators is to reduce the total deployment cost of this new Internet
architecture and to avoid renumbering the site internal routers when
such a site changes ISPs.
3.4. Counterpoint
No counterpoint was submitted for this proposal.
4. Internet Vastly Improved Plumbing (Ivip)
4.1. Summary
4.1.1. Key Ideas
Ivip (pr. eye-vip, est. 2007-06-15) is a core-edge separation scheme
for IPv4 and IPv6. It provides multihoming, portability of address
space and inbound traffic engineering for end-user networks of all
sizes and types, including those of corporations, SOHO and mobile
devices.
Ivip meets all the constraints imposed by the need for widespread
voluntary adoption [Ivip Constraints].
Ivip's global fast-push mapping distribution network is structured
like a cross-linked multicast tree. This pushes all mapping changes
to full database query servers (QSDs) within ISPs and end-user
networks which have ITRs. Each mapping change is sent to all QSDs
within a few seconds.
ITRs gain mapping information from these local QSDs within a few tens
of milliseconds. QSDs notify ITRs of changed mappings with similarly
low latency. ITRs tunnel all traffic packets to the correct ETR
without significant delay.
Ivip's mapping consists of a single ETR address for each range of
mapped address space. Ivip ITRs do not need to test reachability to
ETRs because the mapping is changed in real-time to that of the
desired ETR.
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End-user networks control the mapping, typically by contracting a
specialized company to monitor the reachability of their ETRs and
change the mapping to achieve multihoming and/or Traffic Engineering
(TE). So the mechanisms which control ITR tunneling are controlled
by the end-user networks in real-time and are completely separate
from the core-edge separation scheme itself.
ITRs can be implemented in dedicated servers or hardware-based
routers. The ITR function can also be integrated into sending hosts.
ETRs are relatively simple and only communicate with ITRs rarely -
for Path MTU management with longer packets.
Ivip-mapped ranges of end-user address space need not be subnets.
They can be of any length, in units of IPv4 addresses or IPv6 /64s.
Compared to conventional unscalable BGP techniques, and to the use of
core-edge separation architectures with non-real-time mapping
systems, end-user networks will be able to achieve more flexible and
responsive inbound TE. If inbound traffic is split into several
streams, each to addresses in different mapped ranges, then real-time
mapping changes can be used to steer the streams between multiple
ETRs at multiple ISPs.
Default ITRs in the DFZ (DITRs, similar to LISP's Proxy Tunnel
Routers) tunnel packets sent by hosts in networks which lack ITRs.
So multihoming, portability and TE benefits apply to all traffic.
ITRs request mappings either directly from a local QSD or via one or
more layers of caching query servers (QSCs) which in turn request it
from a local QSD. QSCs are optional but generally desirable since
they reduce the query load on QSDs.
ETRs may be in ISP or end-user networks. IP-in-IP encapsulation is
used, so there is no UDP or any other header. PMTUD (Path MTU
Discovery) management with minimal complexity and overhead will
handle the problems caused by encapsulation, and adapt smoothly to
jumbo frame paths becoming available in the DFZ. The outer header's
source address is that of the sending host - which enables existing
ISP Border Router (BR) filtering of source addresses to be extended
to encapsulated traffic packets by the simple mechanism of the ETR
dropping packets whose inner and outer source address do not match.
4.1.2. Extensions
4.1.2.1. TTR Mobility
The Translating Tunnel Router (TTR) approach to mobility [Ivip
Mobility] is applicable to all core-edge separation techniques and
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provides scalable IPv4 and IPv6 mobility in which the MN keeps its
own mapped IP address(es) no matter how or where it is physically
connected, including behind one or more layers of NAT.
Path-lengths are typically optimal or close to optimal and the MN
communicates normally with all other non-mobile hosts (no stack or
app changes), and of course other MNs. Mapping changes are only
needed when the MN uses a new TTR, which would typically be if the MN
moved more than 1000km. Mapping changes are not required when the MN
changes its physical address(es).
4.1.2.2. Modified Header Forwarding
Separate schemes for IPv4 and IPv6 enable tunneling from ITR to ETR
without encapsulation. This will remove the encapsulation overhead
and PMTUD problems. Both approaches involve modifying all routers
between the ITR and ETR to accept a modified form of the IP header.
These schemes require new FIB/RIB functionality in DFZ and some other
routers but do not alter the BGP functions of DFZ routers.
4.1.3. Gains
Amenable to widespread voluntary adoption due to no need for host
changes, complete support for packets sent from non-upgraded networks
and no significant degradation in performance.
Modular separation of the control of ITR tunneling behavior from the
ITRs and the core-edge separation scheme itself: end-user networks
control mapping in any way they like, in real-time.
A small fee per mapping change deters frivolous changes and helps pay
for pushing the mapping data to all QSDs. End-user networks who make
frequent mapping changes for inbound TE, should find these fees
attractive considering how it improves their ability to utilize the
bandwidth of multiple ISP links.
End-user networks will typically pay the cost of Open ITR in the DFZ
(OITRD) forwarding to their networks. This provides a business model
for OITRD deployment and avoids unfair distribution of costs.
Existing source address filtering arrangements at BRs of ISPs and
end-user networks are prohibitively expensive to implement directly
in ETRs, but with the outer header's source address being the same as
the sending host's address, Ivip ETRs inexpensively enforce BR
filtering on decapsulated packets.
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4.1.4. Costs
QSDs receive all mapping changes and store a complete copy of the
mapping database. However, a worst case scenario is 10 billion IPv6
mappings, each of 32 bytes, which fits on a consumer hard drive today
and should fit in server DRAM by the time such adoption is reached.
The maximum number of non-mobile networks requiring multihoming etc.
is likely to be ~10M, so most of the 10B mappings would be for mobile
devices. However, TTR mobility does not involve frequent mapping
changes since most MNs only rarely move more than 1000km.
4.1.5. References
[I-D.whittle-ivip4-etr-addr-forw] [Ivip PMTUD] [Ivip6] [Ivip
Constraints] [Ivip Mobility] [I-D.whittle-ivip-drtm]
[I-D.whittle-ivip-glossary]
4.2. Critique
Looked at from the thousand foot level, Ivip shares the basic design
approaches with LISP and a number of other Map-and-Encap designs
based on the core-edge separation. However the details differ
substantially. Ivip's design makes a bold assumption that, with
technology advances, one could afford to maintain a real time
distributed global mapping database for all networks and hosts. Ivip
proposes that multiple parties collaborate to build a mapping
distribution system that pushes all mapping information and updates
to local, full database query servers located in all ISPs within a
few seconds. The system has no single point of failure, and uses
end-to-end authentication.
A "real time, globally synchronized mapping database" is a critical
assumption in Ivip. Using that as a foundation, Ivip design avoids
several challenging design issues that others have studied
extensively, that include
1. special considerations of mobility support that add additional
complexity to the overall system;
2. prompt detection of ETR failures and notification to all relevant
ITRs, which turns out to be a rather difficult problem; and
3. development of a partial-mapping lookup sub-system. Ivip assumes
the existence of local query servers with a full database with
the latest mapping information changes.
To be considered as a viable solution to Internet routing scalability
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problem, Ivip faces two fundamental questions. First, whether a
global-scale system can achieve real time synchronized operations as
assumed by Ivip is an entirely open question. Past experiences
suggest otherwise.
The second question concerns incremental rollout. Ivip represents an
ambitious approach, with real-time mapping and local full database
query servers - which many people regard as impossible. Developing
and implementing Ivip may take a fair amount of resources, yet there
is an open question regarding how to quantify the gains by first
movers - both those who will provide the Ivip infrastructure and
those that will use it. Significant global routing table reduction
only happens when a large enough number of parties have adopted Ivip.
The same question arises for most other proposals as well.
One belief is that Ivip's more ambitious mapping system makes a good
design tradeoff for the greater benefits for end-user networks and
for those which develop the infrastructure. Another belief is that
this ambitious design is not viable.
4.3. Rebuttal
Since the Summary and Critique were written, Ivip's mapping system
has been significantly redesigned: DRTM - Distributed Real Time
Mapping [I-D.whittle-ivip-drtm].
DRTM makes it easier for ISPs to install their own ITRs. It also
facilitates Mapped Address Block (MAB) operating companies - which
need not be ISPs - leasing Scalable Provider Independent (SPI)
address space to end-user networks with almost no ISP involvement.
ISPs need not install ITRs or ETRs. For an ISP to support its
customers using SPI space, they need only allow the forwarding of
outgoing packets whose source addresses are from SPI space. End-user
networks can implement their own ETRs on their existing PA
address(es) - and MAB operating companies make all the initial
investments.
Once SPI adoption becomes widespread, ISPs will be motivated to
install their own ITRs to locally tunnel packets sent from customer
networks which must be tunneled to SPI-using customers of the same
ISP - rather than letting these packets exit the ISP's network and
return in tunnels to ETRs in the network.
There is no need for full-database query servers in ISPs or for any
device which stores the full mapping information for all Mapped
Address Blocks (MABs). ISPs that want ITRs will install two or more
Map Resolver (MR) servers. These are caching query servers which
query multiple typically nearby query servers which are full-database
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for the subset of MABs they serve. These "nearby" query servers will
be at DITR sites, which will be run by, or for, MAB operating
companies who lease MAB space to large numbers of end-user networks.
These DITR-site servers will usually be close enough to the MRs to
generate replies with sufficiently low delay and risk of packet loss
for ITRs to buffer initial packets for a few tens of milliseconds
while the mapping arrives.
DRTM will scale to billions of micronets, tens of thousands of MABs
and potentially hundreds of MAB operating companies, without single
points of failure or central coordination.
The critique implies a threshold of adoption is required before
significant routing scaling benefits occur. This is untrue of any
Core-Edge Separation proposal, including LISP and Ivip. Both can
achieve scalable routing benefits in direct proportion to their level
of adoption by providing portability, multihoming and inbound TE to
large numbers of end-user networks.
Core-Edge Elimination (CEE) architectures require all Internet
communications to change to IPv6 with a new Locator/Identifier
Separation naming model. This would impose burdens of extra
management effort, packets and session establishment delays on all
hosts - which is a particularly unacceptable burden on battery-
operated mobile hosts which rely on wireless links.
Core-Edge Separation architectures retain the current, efficient,
naming model, require no changes to hosts and support both IPv4 and
IPv6. Ivip is the most promising architecture for future development
because its scalable, distributed, real-time mapping system best
supports TTR Mobility, enables ITRs to be simpler and gives real-time
control of ITR tunneling to the end-user network or to organizations
they appoint to control the mapping of their micronets.
4.4. Counterpoint
No counterpoint was submitted for this proposal.
5. Hierarchical IPv4 Framework (hIPv4)
5.1. Summary
5.1.1. Key Idea
The Hierarchical IPv4 Framework (hIPv4) adds scalability to the
routing architecture by introducing additional hierarchy in the IPv4
address space. The IPv4 addressing scheme is divided into two parts,
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the Area Locator (ALOC) address space which is globally unique and
the Endpoint Locator (ELOC) address space which is only regionally
unique. The ALOC and ELOC prefixes are added as a shim header
between the IP header and transport protocol header, the shim header
is identified with a new protocol number in the IP header. Instead
of creating a tunneling (i.e. overlay) solution a new routing element
is needed in the service provider's routing domain (called ALOC
realm) - a Locator Swap Router. The current IPv4 forwarding plane
remains intact and no new routing protocols, mapping systems or
caching solutions are required. The control plane of the ALOC realm
routers needs some modification in order for ICMP to be compatible
with the hIPv4 framework. When an area (one or several ASes) of an
ISP has transformed into an ALOC realm, only ALOC prefixes are
exchanged with other ALOC realms. Directly attached ELOC prefixes
are only inserted to the RIB of the local ALOC realm, ELOC prefixes
are not distributed to the DFZ. Multihoming can be achieved in two
ways, either the enterprise requests an ALOC prefix from the RIR
(this is not recommended) or the enterprise receives the ALOC
prefixes from their upstream ISPs. ELOC prefixes are PI addresses
and remain intact when a upstream ISP is changed, only the ALOC
prefix is replaced. When the RIB of the DFZ is compressed
(containing only ALOC prefixes), ingress routers will no longer know
the availability of the destination prefix, thus the endpoints must
take more responsibility for their sessions. This can be achieved by
using multipath enabled transport protocols, such as SCTP (RFC 4960)
and Multipath TCP (MPTCP), at the endpoints. The multipath transport
protocols also provide a session identifier, i.e. verification tag or
token, thus the location and identifier split is carried out - site
mobility, endpoint mobility, and mobile site mobility are achieved.
DNS needs to be upgraded: in order to resolve the location of an
endpoint, the endpoint must have one ELOC value (current A-record)
and at least one ALOC value in DNS (in multihoming solutions there
will be several ALOC values for an endpoint).
5.1.2. Gains
1. Improved routing scalability: Adding additional hierarchy to the
address space enables more hierarchy in the routing architecture.
Early adapters of an ALOC realm will no longer carry the current
RIB of the DFZ - only ELOC prefixes of their directly attached
networks and ALOC prefixes from other service provider that have
migrated are installed in the ALOC realm's RIB.
2. Scalable support for traffic engineering: Multipath enabled
transport protocols are recommended to achieve dynamic load-
balancing of a session. Support for Valiant Load-balancing
[Valiant] schemes has been added to the framework; more research
work is required around VLB switching.
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3. Scalable support for multihoming: Only attachment points of a
multihomed site are advertised (using the ALOC prefix) in the
DFZ. DNS will inform the requester on how many attachment points
the destination endpoint has. It is the initiating endpoint's
choice/responsibility to choose which attachment point is used
for the session; endpoints using multipath enabled transport
protocols can make use of several attachment points for a
session.
4. Simplified Renumbering: When changing provider, the local ELOC
prefixes remains intact, only the ALOC prefix is changed at the
endpoints. The ALOC prefix is not used for routing or forwarding
decisions in the local network.
5. Decoupling Location and Identifier: The verification tag (SCTP)
and token (MPTCP) can be considered to have the characteristics
of a session identifier and thus a session layer is created
between the transport and application layer in the TCP/IP model.
6. Routing quality: The hIPv4 framework introduces no tunneling or
caching mechanisms, only a swap of the content in the IPv4 header
and locator header at the destination ALOC realm is required,
thus current routing and forwarding algorithms are preserved as
such. Valiant Load-balancing might be used as a new forwarding
mechanism.
7. Routing Security: Similar as with today's DFZ, except that ELOC
prefixes can not be hijacked (by injecting a longest match
prefix) outside an ALOC realm.
8. Deployability: The hIPv4 framework is an evolution of the current
IPv4 framework and is backwards compatible with the current IPv4
framework. Sessions in a local network and inside an ALOC realm
might in the future still use the current IPv4 framework.
5.1.3. Costs And Issues
1. Upgrade of the stack at an endpoint that is establishing sessions
outside the local ALOC realm.
2. In a multihoming solution the border routers should be able to
apply policy based routing upon the ALOC value in the locator
header.
3. New IP allocation policies must be set by the RIRs.
4. Short timeframe before the expected depletion of the IPv4 address
space occurs.
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5. Will enterprises give up their current globally unique IPv4
address block allocation they have gained?
6. Coordination with MPTCP is highly desirable.
5.1.4. References
[I-D.frejborg-hipv4]
5.2. Critique
hIPv4 is an innovative approach to expanding the IPv4 addressing
system in order to resolve the scalable routing problem. This
critique does not attempt a full assessment of hIPv4's architecture
and mechanisms. The only question addressed here is whether hIPv4
should be chosen for IETF development in preference to, or together
with, the only two proposals which appear to be practical solutions
for IPv4: Ivip and LISP.
Ivip and LISP appear to have a major advantage over hIPv4 in terms of
support for packets sent from non-upgraded hosts/networks. Ivip's
DITRs (Default ITRs in the DFZ) and LISP's PTRs (Proxy Tunnel
Routers) both accept packets sent by any non-upgraded host/network
and tunnel them to the correct ETR - so providing full benefits of
portability, multihoming and inbound TE for these packets as well as
those sent by hosts in networks with ITRs. hIPv4 appears to have no
such mechanism - so these benefits are only available for
communications between two upgraded hosts in upgraded networks.
This means that significant benefits for adopters - the ability to
rely on the new system to provide the portability, multihoming and
inbound TE benefits for all, or almost all, their communications -
will only arise after all, or almost all networks upgrade their
networks, hosts and addressing arrangements. hIPv4's relationship
between adoption levels and benefits to any adopter therefore are far
less favorable to widespread adoption than those of Core-Edge
Separation (CES) architectures such as Ivip and LISP.
This results in hIPv4 also being at a disadvantage regarding the
achievement of significant routing scaling benefits - which likewise
will only result once adoption is close to ubiquitous. Ivip and LISP
can provide routing scaling benefits in direct proportion to their
level of adoption, since all adopters gain full benefits for all
their communications, in a highly scalable manner.
hIPv4 requires stack upgrades, which are not required by any CES
architecture. Furthermore, a large number of existing IPv4
application protocols convey IP addresses between hosts in a manner
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which will not work with hIPv4: "There are several applications that
are inserting IPv4 address information in the payload of a packet.
Some applications use the IPv4 address information to create new
sessions or for identification purposes. This section is trying to
list the applications that need to be enhanced; however, this is by
no means a comprehensive list." [I-D.frejborg-hipv4]
If even a few widely used applications would need to be rewritten to
operate successfully with hIPv4, then this would be such a
disincentive to adoption to rule out hIPv4 ever being adopted widely
enough to solve the routing scaling problem, especially since CES
architectures fully support all existing protocols, without the need
for altering host stacks.
It appears that hIPv4 involves major practical difficulties which
mean that in its current form it is not suitable for IETF
development.
5.3. Rebuttal
No rebuttal was submitted for this proposal.
5.4. Counterpoint
No counterpoint was submitted for this proposal.
6. Name overlay (NOL) service for scalable Internet routing
6.1. Summary
6.1.1. Key Idea
The basic idea is to add a name overlay (NOL) onto the existing
TCP/IP stack.
Its functions include:
1. Managing host name configuration, registration and
authentication;
2. Initiating and managing transport connection channels (i.e.,
TCP/IP connections) by name;
3. Keeping application data transport continuity for mobility.
At the edge network, we introduce a new type of gateway, a Name
Transfer Relay (NTR), which blocks the PI addresses of edge networks
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into upstream transit networks. NTRs performs address and/or port
translation between blocked PI addresses and globally routable
addresses, which seem like today's widely used NAT/NAPT devices.
Both legacy and NOL applications behind a NTR can access the outside
as usual. To access the hosts behind a NTR from outside, we need to
use NOL traverse the NTR by name and initiate connections to the
hosts behind it.
Different from proposed host-based ID/Locator split solutions, such
as HIP, Shim6, and name-oriented stack, NOL doesn't need to change
the existing TCP/IP stack, sockets and their packet formats. NOL can
co-exist with the legacy infrastructure, and the core-edge separation
solutions (e.g., APT, LISP, Six/one, Ivip, etc.)
6.1.2. Gains
1. Reduce routing table size: Prevent edge network PI address from
leaking into transit network by deploying gateway NTRs.
2. Traffic Engineering: For legacy and NOL application sessions,
the incoming traffic can be directed to a specific NTR by DNS.
In addition, for NOL applications, initial sessions can be
redirected from one NTR to other appropriate NTRs. These
mechanisms provide some support for traffic engineering.
3. Multihoming: When a PI addressed network connects to the
Internet by multihoming with several providers, it can deploy
NTRs to block the PI addresses from leaking into provider
networks.
4. Transparency: NTRs can be allocated PA addresses from the
upstream providers and store them in NTRs' address pool. By DNS
query or NOL session, any session that want to access the hosts
behind the NTR can be delegated to a specific PA address in the
NTR address pool.
5. Mobility: The NOL layer manages the traditional TCP/IP transport
connections, and provides application data transport continuity
by checkpointing the transport connection at sequence number
boundaries.
6. No need to change TCP/IP stack, sockets and DNS system.
7. No need for extra mapping system.
8. NTR can be deployed unilaterally, just like NATs
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9. NOL applications can communicate with legacy applications.
10. NOL can be compatible with existing solutions, such as APT,
LISP, Ivip, etc.
11. End user controlled multipath indirect routing based on
distributed NTRs. This will give benefits to the performance-
aware applications, such as, MSN, Video streaming, etc.
6.1.3. Costs
1. Legacy applications have trouble with initiating access to the
servers behind NTR. Such trouble can be resolved by deploying
NOL proxy for legacy hosts, or delegating globally routable PA
addresses in the NTR address pool for these servers, or deploying
a proxy server outside the NTR.
2. NOL may increase the number of entries in DNS, but it is not
drastic, because it only increases the number of DNS records at
domain granularity not the number of hosts. The name used in
NOL, for example, is similar to an email address
hostname@domain.net. The needed DNS entries and query is just
for "domain.net", and the NTR knows the "hostnames". Not only
will the number of DNS records be increased, but the dynamics of
DNS might be agitated as well. However the scalability and
performance of DNS is guaranteed by its naming hierarchy and
caching mechanisms.
3. Address translating/rewriting costs on NTRs.
6.1.4. References
No references were submitted.
6.2. Critique
1. Applications on hosts need to be rebuilt based on a name overlay
library to be NOL-enabled. The legacy software that is not
maintained will not be able to benefit from NOL in the core-edge
elimination situation. In the core-edge separation scheme, a new
gateway NTR is deployed to prevent edge specific PI prefixes from
leaking into the transit core. NOL doesn't impede the legacy
endpoints behind the NTR from accessing the outside Internet, but
the legacy endpoints cannot or will have difficultly accessing
the endpoints behind a NTR without the help of NOL.
2. In the case of core-edge elimination, the end site will be
assigned multiple PA address spaces, which leads to renumbering
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troubles when switching to other upstream providers. Upgrading
endpoints to support NOL doesn't give any benefits to edge
networks. Endpoints have little incentive to use NOL in a core-
edge elimination scenario, and the same is true with other host-
based ID/locator split proposals. Edge networks prefer PI
address space to PA address space whether they are IPv4 or IPv6
networks.
3. In the core-edge separation scenario, the additional gateway NTR
is to prevent the specific prefixes from the edge networks, just
like a NAT or the ITR/ETR of LISP. A NTR gateway can be seen as
an extension of NAT (Network Address Translation). Although NATs
are deployed widely, upgrading them to support NOL extension or
deploying additional new gateway NTRs at the edge networks are on
a voluntary basis and have few economic incentives.
4. The stateful or stateless translation for each packet traversing
a NTR will require the cost of the CPU and memory of NTRs, and
increase forwarding delay. Thus, it is not appropriate to deploy
NTRs at the high-level transit networks where aggregated traffic
may cause congestion at the NTRs.
5. In the core-edge separation scenario, the requirement for
multihoming and inter-domain traffic engineering will make end
sites accessible via multiple different NTRs. For reliability,
all of the associations between multiple NTRs and the end site
name will be kept in DNS, which may increase the load of DNS.
6. To support mobility, it is necessary for DNS to update the
corresponding name-NTR mapping records when an end system moves
from behind one NTR to another NTR. The NOL-enabled end relies
on the NOL layer to preserve the continuity of the transport
layer, since the underlying TCP/UDP transport session would be
broken when the IP address changed.
6.3. Rebuttal
NOL resembles neither CEE nor CES as a solution. By supporting
application level session through the name overlay layer, NOL can
support some solutions in the CEE style. However, NOL is in general
closer to CES solutions, i.e., preventing PI prefixes of edge
networks from entering into the upstream transit networks. This is
done by the NTR, like the ITR/ETRs in CES solutions, but NOL has no
need to define the clear boundary between core and edge networks.
NOL is designed to try to provide end users or networks a service
that facilitates the adoption of multihoming, multipath routing and
traffic engineering by the indirect routing through NTRs, and, in the
mean time, doesn't accelerate, or decrease, the growth of global
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routing table size.
Some problems are described in the NOL critique. In the original NOL
proposal document, the DNS query for a host that is behind a NTR will
induce the return of the actual IP addresses of the host and the
address of the NTR. This arrangement might cause some difficulties
for legacy applications due to the non-standard response from DNS.
To resolve this problem, we instead have the NOL service use a new
namespace, and have DNS not return NTR IP address for the legacy
hosts. The names used for NOL are formatted like email addresses,
such as "des@domain.net". The mapping between "domain.net" and IP
address of corresponding NTR will be registered in DNS. The NOL
layer will understand the meaning of the name "des@domain.net" , and
it will send a query to DNS only for "domain.net". DNS will then
return IP addresses of the corresponding NTRs. Legacy applications,
will still use the traditional FQDN name and DNS will return the
actual IP address of the host. However, if the host is behind a NTR,
the legacy applications may be unable to access the host.
The stateless address translation or stateful address and port
translation may cause a scaling problem with the number of table
entries NTR must maintain. And legacy applications can not initiate
sessions with hosts inside the NOL-adopting End User Network (EUN).
However, these problems may not be a big barrier for the deployment
of NOL or other similar approaches. Many NAT-like boxes, proxy, and
firewall devices are widely used at the Ingress/Egress points of
Enterprise networks, campus networks or other stub EUNs. The hosts
running as servers can be deployed outside NTRs or be assigned PA
addresses in a NTR-adopting EUN.
6.4. Counterpoint
No counterpoint was submitted for this proposal.
7. Compact routing in locator identifier mapping system (CRM)
7.1. Summary
7.1.1. Key Idea
This proposal is to build a highly scalable locator identity mapping
system using compact routing principles. This provides the means for
dynamic topology adaption to facilitate efficient aggregation [CRM].
Map servers are assigned as cluster heads or landmarks based on their
capability to aggregate EID announcements.
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7.1.2. Gains
Minimizes the routing table sizes at the system level (i.e., map
servers). Provides clear upper bounds for routing stretch that
define the packet delivery delay of the map request/first packet.
Organizes the mapping system based on the EID numbering space,
minimizes the administrative overhead of managing the EID space. No
need for administratively planned hierarchical address allocation as
the system will find convergence into a set of EID allocations.
Availability and robustness of the overall routing system (including
xTRs and map servers) is improved because of the potential to use
multiple map servers and direct routes without the involvement of map
servers.
7.1.3. Costs
The scalability gains will materialize only in large deployments. If
the stretch is bounded to those of compact routing (worst case
stretch less or equal to 3, on average 1+epsilon) then xTRs need to
have memory/cache for the mappings of its cluster.
7.1.4. References
[CRM]
7.2. Critique
The CRM proposal is not a complete proposal, and therefore cannot be
considered for further development by the IETF as a scalable routing
solution.
While Compact Routing principles may be able to improve a mapping
overlay structure such as LISP-ALT there are several objections to
this approach.
Firstly, a CRM-modified ALT structure would still be a global query
server system. No matter how ALT's path lengths and delays are
optimized, there is a problem with a querier - which could be
anywhere in the world - relying on mapping information from one or
ideally two or more authoritative query servers, which could also be
anywhere in the world. The delays and risks of packet loss that are
inherent in such a system constitute a fundamental problem. This is
especially true when multiple, potentially long, traffic streams are
received by ITRs and forwarded over the CRM networks for delivery to
the destination network. ITRs must use the CRM infrastructure while
they are awaiting a map reply. The traffic forwarded on the CRM
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infrastructure functions as map requests and can present a
scalability and performance issue to the infrastructure.
Secondly, the alterations contemplated in this proposal involve the
roles of particular nodes in the network being dynamically assigned
as part of its self-organizing nature.
The discussion of Clustering in the middle of page 4 also indicates
that particular nodes are responsible for registering EIDs from
typically far-distant ETRs, all of which are handling closely related
EIDs which this node can aggregate. Since MSes are apparently nodes
within the compact routing system, and the process of an MS deciding
whether to accept EID registrations is determined as part of the
self-organizing properties of the system, there are concerns about
how EID registration can be performed securely, when no particular
physical node is responsible for it.
Thirdly there are concerns about individually owned nodes performing
work for other organizations. Such problems of trust and of
responsibilities and costs being placed on those who do not directly
benefit already exist in the interdomain routing system, and are a
challenge for any scalable routing solution.
There are simpler solutions to the mapping problem than having an
elaborate network of routers. If a global-scale query system is
still preferred, then it would be better to have ITRs use local MRs,
each of which is dynamically configured to know the IP address of the
million or so authoritative Map Server (MS) query servers - or two
million or so assuming they exist in pairs for redundancy.
It appears that the inherently greater delays and risks of packet
loss of any global query server system make them unsuitable mapping
solutions for Core-Edge Elimination or Core-Edge Separation
architectures. The solution to these problems appears to involve a
greater number of widely distributed authoritative query servers, one
or more of which will therefore be close enough to each querier that
delays and risk of packet loss are reduced to acceptable levels.
Such a structure would be suitable for map requests, but perhaps not
for handling traffic packets to be delivered to the destination
networks.
7.3. Rebuttal
CRM is most easily understood as an alteration to the routing
structure of the LISP-ALT mapping overlay system, by altering or
adding to the network's BGP control plane.
CRM's aims include the delivery of initial traffic packets to their
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destination networks where they also function as map requests. These
packet streams may be long and numerous in the fractions of a second
to perhaps several seconds that may elapse before the ITR receives
the map reply.
Compact Routing principles are used to optimize the path length taken
by these query or traffic packets through a significantly modified
version of the ALT (or similar) network while also generally reducing
typical or maximum paths taken by the query packets.
An overlay network is a diversion from the shortest path. However,
CMR limits this diversion and provides an upper bound. Landmark
routers/servers could deliver more than just the first traffic
packet, subject to their CPU capabilities and their network
connectivity bandwidths.
The trust between the landmarks (mapping servers) can be built based
on the current BGP relationships. Registration to the landmark nodes
needs to be authenticated mutually between the MS and the system that
is registering. This part is not documented in the proposal text.
7.4. Counterpoint
No counterpoint was submitted for this proposal.
8. Layered mapping system (LMS)
8.1. Summary
8.1.1. Key Ideas
The layered mapping system proposal builds a hierarchical mapping
system to support scalability, analyzes the design constraints and
presents an explicit system structure; designs a two-cache mechanism
on ingress tunneling router (ITR) to gain low request delay and
facilitates data validation. Tunneling and mapping are done at the
core and no change is needed on edge networks. The mapping system is
run by interest groups independent of any ISP, which conforms to
economical model and can be voluntarily adopted by various networks.
Mapping systems can also be constructed stepwise, especially in the
IPv6 scenario.
8.1.2. Gains
1. Scalability
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1. Distributed storage of mapping data avoids central storage of
massive amounts of data and restricts updates within local
areas.
2. The cache mechanism in an ITR reduces request loads on
mapping system reasonably.
2. Deployability
1. No change on edge systems, only tunneling in core routers,
and new devices in core networks.
2. The mapping system can be constructed stepwise: a mapping
node needn't be constructed if none of its responsible ELOCs
is allocated. This makes sense especially for IPv6.
3. Conforms to a viable economic model: the mapping system
operators can profit from their services; core routers and
edge networks are willing to join the circle either to avoid
router upgrades or realize traffic engineering. Benefits
from joining are independent of the scheme's implementation
scale.
3. Low request delay: The low number of layers in the mapping
structure and the two-stage cache help achieve low request delay.
4. Data consistency: The two-stage cache enables an ITR to update
data in the map cache conveniently.
5. Traffic engineering support: Edge networks inform the mapping
system of their prioritized mappings with all upstream routers,
thus giving the edge networks control over their ingress flows.
8.1.3. Costs
1. Deployment of LMS needs to be further discussed.
2. The structure of mapping system needs to be refined according to
practical circumstances.
8.1.4. References
[LMS Summary] [LMS]
8.2. Critique
LMS is a mapping mechanism based on core-edge separation. In fact,
any proposal that needs a global mapping system with keys with
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similar properties to that of an "edge address" in a core-edge
separation scenario can use such a mechanism. This means that those
keys are globally unique (by authorization or just statistically), at
the disposal of edge users, and may have several satisfied mappings
(with possibly different weights). A proposal to address routing
scalability that needs mapping but doesn't specify the mapping
mechanism can use LMS to strengthen its infrastructure.
The key idea of LMS is similar to that of LISP+ALT: that the mapping
system should be hierarchically organized to gain scalability for
storage and updates, and to achieve quick indexing for lookups.
However, LMS advocates an ISP-independent mapping system and ETRs are
not the authorities of mapping data. ETRs or edge-sites report their
mapping data to related mapping servers.
LMS assumes that mapping servers can be incrementally deployed in
that a server may not be constructed if none of its administered edge
addresses are allocated, and that mapping servers can charge for
their services, which provides the economic incentive for their
existence. How this brand-new system can be constructed is still not
clear. Explicit layering is only an ideal state, and the proposal
analyzes the layering limits and feasibility, rather than provide a
practical way for deployment.
The drawbacks of LMS's feasibility analysis also include that it 1)
is based on current PC power and may not represent future
circumstances (especially for IPv6), and 2) does not consider the
variability of address utilization. Some IP address spaces may be
effectively allocated and used while some may not, causing some
mapping servers to be overloaded while others poorly utilized. More
thoughts are needed as to the flexibility of the layer design.
LMS doesn't fit well for mobility. It does not solve the problem
when hosts move faster than the mapping updates and propagation
between relative mapping servers. On the other hand, mobile hosts
moving across ASes and changing their attachment points (core
addresses) is less frequent than hosts moving within an AS.
Separation needs two planes: core-edge separation, which is to gain
routing table scalability and identity-location separation, which is
to achieve mobility. GLI does a good clarification of this and in
that case, LMS can be used to provide identity-to-core address
mapping. Of course, other schemes may be competent and LMS can be
incorporated with them if the scheme has global keys and needs to map
them to other namespaces.
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8.3. Rebuttal
No rebuttal was submitted for this proposal.
8.4. Counterpoint
No counterpoint was submitted for this proposal.
9. 2-phased mapping
9.1. Summary
9.1.1. Considerations
1. A mapping from prefixes to ETRs is an M:M mapping. Any change of
a (prefix, ETR) pair should be updated in a timely manner which
can be a heavy burden to any mapping system if the relation
changes frequently.
2. A prefix<->ETR mapping system cannot be deployed efficiently if
it is overwhelmed by the worldwide dynamics. Therefore the
mapping itself is not scalable with this direct mapping scheme.
9.1.2. Basics of a 2-phased mapping
1. Introduce an AS number in the middle of the mapping, the phase I
mapping is prefix<->AS#, phase II mapping is AS#<->ETRs. This
creates a M:1:M mapping model.
2. It is fair to assume that all ASes know their local prefixes (in
the IGP) better than others and that it is most likely that local
prefixes can be aggregated when they can be mapped to the AS
number, which will reduce the number of mapping entries. ASes
also know clearly their ETRs on the border between core and edge.
So all mapping information can be collected locally.
3. A registry system will take care of the phase I mapping
information. Each AS should have a registration agent to notify
the registry of the local range of IP address space. This system
can be organized as a hierarchical infrastructure like DNS, or
alternatively as a centralized registry like "whois" in each RIR.
Phase II mapping information can be distributed between xTRs as a
BGP extension.
4. The basic forwarding procedure is that the ITR first gets the
destination AS number from the phase I mapper (or from cache)
when the packet is entering the "core". Then it will extract the
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closest ETR for the destination AS number. This is local, since
phase II mapping information has been "pushed" to it through BGP
updates. Finally, the ITR tunnels the packet to the
corresponding ETR.
9.1.3. Gains
1. Any prefix reconfiguration (aggregation/deaggregation) within an
AS will not be reflected in the mapping system.
2. Local prefixes can be aggregated with a high degree of
efficiency.
3. Both phase I and phase II mappings can be stable.
4. A stable mapping system will reduce the update overhead
introduced by topology changes and/or routing policy dynamics.
9.1.4. Summary
1. The 2-phased mapping scheme introduces an AS number between the
mapping prefixes and ETRs.
2. The decoupling of direct mapping makes highly dynamic updates
stable, therefore it can be more scalable than any direct mapping
designs.
3. The 2-phased mapping scheme is adaptable to any core/edge split
based proposals.
9.1.5. References
No references were submitted.
9.2. Critique
This is a simple idea on how to scale mapping. However, this design
is too incomplete to be considered a serious input to RRG. Take the
following 2 issues as example:
First, in this 2-phase scheme, an AS is essentially the unit of
destinations (i.e. sending ITRs find out destination AS D, then send
data to one of of D's ETR). This does not offer much choice for
traffic engineering.
Second, there is no consideration whatsoever on failure detection and
handling.
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9.3. Rebuttal
No rebuttal was submitted for this proposal.
9.4. Counterpoint
No counterpoint was submitted for this proposal.
10. Global Locator, Local Locator, and Identifier Split (GLI-Split)
10.1. Summary
10.1.1. Key Idea
GLI-Split implements a separation between global routing (in the
global Internet outside edge networks) and local routing (inside edge
networks) using global and local locators (GLs, LLs). In addition, a
separate static identifier (ID) is used to identify communication
endpoints (e.g. nodes or services) independently of any routing
information. Locators and IDs are encoded in IPv6 addresses to
enable backwards-compatibility with the IPv6 Internet. The higher
order bits store either a GL or a LL while the lower order bits
contain the ID. A local mapping system maps IDs to LLs and a global
mapping system maps IDs to GLs. The full GLI-mode requires nodes
with upgraded networking stacks and special GLI-gateways. The GLI-
gateways perform stateless locator rewriting in IPv6 addresses with
the help of the local and global mapping system. Non-upgraded IPv6
nodes can also be accommodated in GLI-domains since an enhanced DHCP
service and GLI-gateways compensate their missing GLI-functionality.
This is an important feature for incremental deployability.
10.1.2. Gains
The benefits of GLI-Split are
o Hierarchical aggregation of routing information in the global
Internet through separation of edge and core routing
o Provider changes not visible to nodes inside GLI-domains
(renumbering not needed)
o Rearrangement of subnetworks within edge networks not visible to
the outside world (better support of large edge networks)
o Transport connections survive both types of changes
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o Multihoming
o Improved traffic engineering for incoming and outgoing traffic
o Multipath routing and load balancing for hosts
o Improved resilience
o Improved mobility support without home agents and triangle routing
o Interworking with the classic Internet
* without triangle routing over proxy routers
* without stateful NAT
These benefits are available for upgraded GLI-nodes, but non-upgraded
nodes in GLI-domains partially benefit from these advanced features,
too. This offers multiple incentives for early adopters and they
have the option to migrate their nodes gradually from non-GLI stacks
to GLI-stacks.
10.1.3. Costs
o Local and global mapping system
o Modified DHCP or similar mechanism
o GLI-gateways with stateless locator rewriting in IPv6 addresses
o Upgraded stacks (only for full GLI-mode)
10.1.4. References
[GLI] [Valiant]
10.2. Critique
GLI-Split makes a clear distinction between two separation planes:
the separation between identifier and locator, which is to meet end-
users needs including mobility; and the separation between local and
global locator, to make the global routing table scalable. The
distinction is needed since ISPs and hosts have different
requirements, also make the changes inside and outside GLI-domains
invisible to their opposites.
A main drawback of GLI-Split is that it puts a burden on hosts.
Before routing a packet received from upper layers, network stacks in
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hosts first need to resolve the DNS name to an IP address; if the IP
address is GLI-formed, it may look up the map from the identifier
extracted from the IP address to the local locator. If the
communication is between different GLI-domains, hosts may further
look up the mapping from the identifier to the global locator.
Having the local mapping system forward requests to the global
mapping system for hosts is just an option. Though host lookup may
ease the burden of intermediate nodes which would otherwise to
perform the mapping lookup, the three lookups by hosts in the worst
case may lead to large delays unless a very efficient mapping
mechanism is devised. The work may also become impractical for low-
powered hosts. On one hand, GLI-split can provide backward
compatibility where classic and upgraded IPv6 hosts can communicate,
which is its big virtue; while the upgrades may work against hosts'
enthusiasm to change, compared to the benefits they would gain.
GLI-split provides additional features to improve TE and to improve
resilience, e.g., exerting multipath routing. However the cost is
that more burdens are placed on hosts, e.g. they may need more lookup
actions and route selections. However, these kinds of tradeoffs
between costs and gains exists in most proposals.
One improvement of GLI-Split is its support for mobility by updating
DNS data as GLI-hosts move across GLI-domains. Through this the GLI-
corresponding-node can query DNS to get a valid global locator of the
GLI-mobile-node and need not query the global mapping system (unless
it wants to do multipath routing), giving more incentives for nodes
to become GLI-enabled. The merits of GLI-Split, simplified-mobility-
handover provision, compensates for the costs of this improvement.
GLI-Split claims to use rewriting instead of tunneling for
conversions between local and global locators when packets span GLI-
domains. The major advantage is that this kind of rewriting needs no
extra state, since local and global locators need not map to each
other. Many other rewriting mechanisms instead need to maintain
extra state. It also avoids the MTU problem faced by the tunneling
methods. However, GLI-Split achieves this only by compressing the
namespace size of each attribute (identifier, local and global
locator). GLI-Split encodes two namespaces (identifier and local/
global locator) into an IPv6 address, each has a size of 2^64 or
less, while map-and-encap proposals assume that identifier and
locator each occupy a 128 bit space.
10.3. Rebuttal
The arguments in the GLI-Split critique are correct. There are only
two points that should be clarified here. (1) First, it is not a
drawback that hosts perform the mapping lookups. (2) Second, the
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critique proposed an improvement to the mobility mechanism, which is
of general nature and not specific to GLI-Split.
1. The additional burden on the hosts is actually a benefit,
compared to having the same burden on the gateways. If the
gateway would perform the lookups and packets addressed to
uncached EIDs arrive, a lookup in the mapping system must be
initiated. Until the mapping reply returns, packets must be
either dropped, cached, or the packets must be sent over the
mapping system to the destination. All these options are not
optimal and have their drawbacks. To avoid these problems in
GLI-Split, the hosts perform the lookup. The short additional
delay is not a big issue in the hosts because it happens before
the first packets are sent. So no packets are lost or have to be
cached. GLI-Split could also easily be adapted to special GLI-
hosts (e.g., low power sensor nodes) that do not have to do any
lookup and simply let the gateway do all the work. This
functionality is included anyway for backward compatibility with
regular IPv6-hosts inside the GLI-domain.
2. The critique proposes a DNS-based mobility mechanism as an
improvement to GLI-Split. However, this improvement is an
alternative mobility approach which can be applied to any routing
architecture including GLI-Split and raises also some concerns,
e.g., the update speed of DNS. Therefore, we prefer to keep this
issue out of the discussion.
10.4. Counterpoint
No counterpoint was submitted for this proposal.
11. Tunneled Inter-domain Routing (TIDR)
11.1. Summary
11.1.1. Key Idea
Provides a method for locator-identifier separation using tunnels
between routers on the edge of the Internet transit infrastructure.
It enriches the BGP protocol for distributing the identifier-to-
locator mapping. Using new BGP attributes, "identifier prefixes" are
assigned inter-domain routing locators so that they will not be
installed in the RIB and will be moved to a new table called Tunnel
Information Base (TIB). Afterwards, when routing a packet to an
"identifier prefix", the TIB will be searched first to perform
tunneling, and secondly the RIB for actual routing. After the edge
router performs tunneling, all routers in the middle will route this
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packet until the router at the tail-end of the tunnel.
11.1.2. Gains
o Smooth deployment
o Size reduction of the global RIB
o Deterministic customer traffic engineering for incoming traffic
o Numerous forwarding decisions for a particular address prefix
o Stops AS number space depletion
o Improved BGP convergence
o Protection of the inter-domain routing infrastructure
o Easy separation of control traffic and transit traffic
o Different layer-2 protocol-IDs for transit and non-transit traffic
o Multihoming resilience
o New address families and tunneling techniques
o Support for IPv4 or IPv6, and migration to IPv6
o Scalability, stability and reliability
o Faster inter-domain routing
11.1.3. Costs
o Routers on the edge of the inter-domain infrastructure will need
to be upgraded to hold the mapping database (i.e. the TIB)
o "Mapping updates" will need to be treated differently from usual
BGP "routing updates"
11.1.4. References
[I-D.adan-idr-tidr] [TIDR identifiers] [TIDR and LISP] [TIDR AS
forwarding]
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11.2. Critique
TIDR is a Core-Edge Separation architecture from late 2006 which
distributes its mapping information via BGP messages which are passed
between DFZ routers.
This means that TIDR cannot solve the most important goal of scalable
routing - to accommodate much larger numbers of end-user network
prefixes (millions or billions) without each such prefix directly
burdening every DFZ router. Messages advertising routes for TIDR-
managed prefixes may be handled with lower priority, but this would
only marginally reduce the workload for each DFZ router compared to
handling an advertisement of a conventional PI prefix.
Therefore, TIDR cannot be considered for RRG recommendation as a
solution to the routing scaling problem.
For a TIDR-using network to receive packets sent from any host, every
BR of all ISPs must be upgraded to have the new ITR-like
functionality. Furthermore, all DFZ routers would need to be altered
so they accepted and correctly propagated the routes for end-user
network address space, with the new LOCATOR attribute which contains
the ETR address and a REMOTE-PREFERENCE value. Firstly, if they
received two such advertisements with different LOCATORs, they would
advertise a single route to this prefix containing both. Secondly,
for end-user address space (for IPv4) to be more finely divided, the
DFZ routers must propagate LOCATOR-containing advertisements for
prefixes longer than /24.
TIDR's ITR-like routers store the full mapping database - so there
would be no delay in obtaining mapping, and therefore no significant
delay in tunneling traffic packets.
The TIDR ID is written as if traffic packets are classified by
reference to the RIB - but routers use the FIB for this purpose, and
"FIB" does not appear in the ID.
TIDR does not specify a tunneling technique, leaving this to be
chosen by the ETR-like function of BRs and specified as part of a
second-kind of new BGP route advertised by that ETR-like BR. There
is no provision for solving the PMTUD problems inherent in
encapsulation-based tunneling.
ITR functions must be performed by already busy routers of ISPs,
rather than being distributed to other routers or to sending hosts.
There is no practical support for mobility. The mapping in each end-
user route advertisement includes a REMOTE-PREFERENCE for each ETR-
like BR, but this is used by the ITR-like functions of BRs to always
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select the LOCATOR with the highest value. As currently described,
TIDR does not provide inbound load splitting TE.
Multihoming service restoration is achieved initially by the ETR-like
function of BR at the ISP whose link to the end-user network has just
failed, looking up the mapping to find the next preferred ETR-like
BR's address. The first ETR-like router tunnels the packets to the
second ETR-like router in the other ISP. However, if the failure was
caused by the first ISP itself being unreachable, then connectivity
would not be restored until a revised mapping (with higher REMOTE-
PREFERENCE) from the reachable ETR-like BR of the second ISP
propagated across the DFZ to all ITR-like routers, or the withdrawn
advertisement for the first one reaches the ITR-like router.
11.3. Rebuttal
No rebuttal was submitted for this proposal.
11.4. Counterpoint
No counterpoint was submitted for this proposal.
12. Identifier-Locator Network Protocol (ILNP)
12.1. Summary
12.1.1. Key Ideas
o Provides crisp separation of Identifiers from Locators.
o Identifiers name nodes, not interfaces.
o Locators name subnetworks, rather than interfaces, so they are
equivalent to an IP routing prefix.
o Identifiers are never used for network-layer routing, whilst
Locators are never used for Node Identity.
o Transport-layer sessions (e.g. TCP session state) use only
Identifiers, never Locators, meaning that changes in location have
no adverse impact on an IP session.
12.1.2. Benefits
o The underlying protocol mechanisms support fully scalable site
multihoming, node multihoming, site mobility, and node mobility.
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o ILNP enables topological aggregation of location information while
providing stable and topology-independent identities for nodes.
o In turn, this topological aggregation reduces both the routing
prefix "churn" rate and the overall size of the Internet's global
routing table, by eliminating the value and need for more-specific
routing state currently carried throughout the global (default-
free) zone of the routing system.
o ILNP enables improved Traffic Engineering capabilities without
adding any state to the global routing system. TE capabilities
include both provider-driven TE and also end-site-controlled TE.
o ILNP's mobility approach:
* eliminates the need for special-purpose routers (e.g. Home
Agent and/or Foreign Agent now required by Mobile IP & NEMO).
* eliminates "triangle routing" in all cases.
* supports both "make before break" and "break before make"
layer-3 handoffs.
o ILNP improves resilience and network availability while reducing
the global routing state (as compared with the currently deployed
Internet).
o ILNP is Incrementally Deployable:
* No changes are required to existing IPv6 (or IPv4) routers.
* Upgraded nodes gain benefits immediately ("day one"); those
benefits gain in value as more nodes are upgraded (this follows
Metcalfe's Law).
* Incremental Deployment approach is documented.
o ILNP is Backwards Compatible:
* ILNPv6 is fully backwards compatible with IPv6 (ILNPv4 is fully
backwards compatible with IPv4).
* Reuses existing known-to-scale DNS mechanisms to provide
identifier/locator mapping.
* Existing DNS Security mechanisms are reused without change.
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* Existing IP Security mechanisms are reused with one minor
change (IPsec Security Associations replace the current use of
IP Addresses with the use of Identifier values). NB: IPsec is
also backwards compatible.
* Backwards Compatibility approach is documented.
o No new or additional overhead is required to determine or to
maintain locator/path liveness.
o ILNP does not require locator rewriting (NAT); ILNP permits and
tolerates NAT should that be desirable in some deployment(s).
o Changes to upstream network providers do not require node or
subnetwork renumbering within end-sites.
o Compatible with and can facilitate the transition from current
single-path TCP to multipath TCP.
o ILNP can be implemented such that existing applications (e.g.
applications using the BSD Sockets API) do NOT need any changes or
modifications to use ILNP.
12.1.3. Costs
o End systems need to be enhanced incrementally to support ILNP in
addition to IPv6 (or IPv4 or both).
o DNS servers supporting upgraded end systems also should be
upgraded to support new DNS resource records for ILNP. (DNS
protocol & DNS security do not need any changes.)
12.1.4. References
[ILNP Site] [MobiArch1] [MobiArch2] [MILCOM1] [MILCOM2] [DNSnBIND]
[I-D.carpenter-behave-referral-object] [I-D.rja-ilnp-nonce] [RFC4033]
[RFC4034] [RFC4035] [RFC5534] [RFC5902]
12.2. Critique
The primary issue for ILNP is how the deployment incentives and
benefits line up with the RRG goal of reducing the rate of growth of
entries and churn in the core routing table. If a site is currently
using PI space, it can only stop advertising that space when the
entire site is ILNP capable. This needs at least clear elucidation
of the incentives for ILNP which are not related to routing scaling,
in order for there to be a path for this to address the RRG needs.
Similarly, the incentives for upgrading hosts need to align with the
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value for those hosts.
A closely related question is whether this mechanism actually
addresses the sites need for PI addresses. Assuming ILNP is
deployed, the site does achieve flexible, resilient, communication
using all of its Internet connections. While the proposal addresses
the host updates when the host learns of provider changes, there are
other aspects of provider change that are not addressed. This
includes renumbering router, subnets, and certain servers. (It is
presumed that most servers, once the entire site has moved to ILNP,
will not be concerned if their locator changes. However, some
servers must have known locators, such as the DNS server.) The
issues described in [RFC5887] will be ameliorated, but not resolved.
To be able to adopt this proposal, and have sites use it, we need to
address these issues. When a site changes points of attachment only
a small amount of DNS provisioning should be required. The LP record
is apparently intended to help with this. It is also likely that the
use of dynamic DNS will help this.
The ILNP mechanism is described as being suitable for use in
conjunction with mobility. This raises the question of race
conditions. To the degree that mobility concerns are valid at this
time, it is worth asking how communication can be established if a
node is sufficiently mobile that it is moving faster than the DNS
update and DNS fetch cycle can effectively propagate changes.
This proposal does presume that all communication using this
mechanism is tied to DNS names. While it is true that most
communication does start from a DNS name, it is not the case that all
exchanges have this property. Some communication initiation and
referral can be done with an explicit I/L pair. This does appear to
require some extensions to the existing mechanism (for both sides to
add locators). In general, some additional clarity on the
assumptions regarding DNS, particularly for low end devices, would
seem appropriate.
One issue that this proposal shares with many others is the question
of how to determine which locator pairs (local and remote) are
actually functional. This is an issue both for initial
communications establishment, and for robustly maintaining
communication. While it is likely that a combination of monitoring
of traffic (in the host, where this is tractable), coupled with other
active measures, can address this. ICMP is clearly insufficient.
12.3. Rebuttal
ILNP eliminates the perceived need for PI addressing, and encourages
increased DFZ aggregation. Many enterprise users view DFZ scaling
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issues as too abstruse. So ILNP creates more user-visible incentives
to upgrade deployed systems.
ILNP mobility eliminates Duplicate Address Detection (DAD), reducing
the layer-3 handoff time significantly, compared to IETF standard
Mobile IP. [MobiArch1] [MobiArch2] ICMP Location updates separately
reduce the layer-3 handoff latency.
Also, ILNP enables both host multihoming and site multihoming.
Current BGP approaches cannot support host multihoming. Host
multihoming is valuable in reducing the site's set of externally
visible nodes.
Improved mobility support is very important. This is shown by the
research literature and also appears in discussions with vendors of
mobile devices (smartphones, MP3-players). Several operating system
vendors push "updates" with major networking software changes in
maintenance releases today. Security concerns mean most hosts
receive vendor updates more quickly these days.
ILNP enables a site to hide exterior connectivity changes from
interior nodes, using various approaches. One approach deploys
unique local address (ULA) prefixes within the site and has the site
border router(s) rewrite the Locator values. The usual NAT issues
don't arise because the Locator value is not used above the network-
layer. [MILCOM1] [MILCOM2]
[RFC5902] makes clear that many users desire IPv6 NAT, with site
interior obfuscation as a major driver. This makes global-scope PI
addressing much less desirable for end sites than formerly.
ILNP-capable nodes can talk existing IP with legacy IP-only nodes,
with no loss of current IP capability. So ILNP-capable nodes will
never be worse off.
Secure Dynamic DNS Update is standard, and widely supported in
deployed hosts and DNS servers. [DNSnBIND] says many sites have
deployed this technology without realizing it (e.g. by enabling both
the DHCP server and Active Directory of MS-Windows Server).
If a node is as mobile as the critique says, then existing IETF
Mobile IP standards also will fail. They also use location updates
(e.g. MN->HA, MN->FA).
ILNP also enables new approaches to security that eliminate
dependence upon location-dependent ACLs without packet
authentication. Instead, security appliances track flows using
Identifier values, and validate the I/L relationship
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cryptographically [RFC4033] [RFC4034] [RFC4035] or non-
cryptographically by reading the [I-D.rja-ilnp-nonce].
The DNS LP record has a more detailed explanation now. LP records
enable a site to change its upstream connectivity by changing the L
records of a single FQDN covering the whole site, providing
scalability.
DNS-based server load balancing works well with ILNP by using DNS SRV
records. DNS SRV records are not new, are widely available in DNS
clients & servers, and are widely used today in the IPv4 Internet for
Server Load Balancing.
Recent ILNP I-Ds discuss referrals in more detail. A node with a
binary-referral can find the FQDN using DNS PTR records, which can be
authenticated [RFC4033] [RFC4034] [RFC4035]. Approaches such as
[I-D.carpenter-behave-referral-object] improve user experience and
user capability, so are likely to self-deploy.
Selection from multiple Locators is identical to an IPv4 system
selecting from multiple A records for its correspondent. Deployed IP
nodes can track reachability via existing host mechanisms, or by
using the SHIM6 method. [RFC5534]
12.4. Counterpoint
No counterpoint was submitted for this proposal.
13. Enhanced Efficiency of Mapping Distribution Protocols in Map-and-
Encap Schemes (EEMDP)
13.1. Summary
13.1.1. Introduction
We present some architectural principles pertaining to the mapping
distribution protocols, especially applicable to map-and-encap (e.g.,
LISP) type of protocols. These principles enhance the efficiency of
the map-and-encap protocols in terms of (1) better utilization of
resources (e.g., processing and memory) at Ingress Tunnel Routers
(ITRs) and mapping servers, and consequently, (2) reduction of
response time (e.g., first packet delay). We consider how Egress
Tunnel Routers (ETRs) can perform aggregation of end-point ID (EID)
address space belonging to their downstream delivery networks, in
spite of migration/re-homing of some subprefixes to other ETRs. This
aggregation may be useful for reducing the processing load and memory
consumption associated with map messages, especially at some
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resource-constrained ITRs and subsystems of the mapping distribution
system. We also consider another architectural concept where the
ETRs are organized in a hierarchical manner for the potential benefit
of aggregation of their EID address spaces. The two key
architectural ideas are discussed in some more detail below. A more
complete description can be found in [EEMDP Considerations] and
[EEMDP Presentation].
It will be helpful to refer to Figures 1, 2, and 3 in the document
noted above for some of the discussions that follow here below.
13.1.2. Management of Mapping Distribution of Subprefixes Spread Across
Multiple ETRs
To assist in this discussion, we start with the high level
architecture of a map-and-encap approach (it would be helpful to see
Fig. 1 in the document mentioned above). In this architecture we
have the usual ITRs, ETRs, delivery networks, etc. In addition, we
have the ID-Locator Mapping (ILM) servers which are repositories for
complete mapping information, while the ILM-Regional (ILM-R) servers
can contain partial and/or regionally relevant mapping information.
While a large endpoint address space contained in a prefix may be
mostly associated with the delivery networks served by one ETR, some
fragments (subprefixes) of that address space may be located
elsewhere at other ETRs. Let a/20 denote a prefix that is
conceptually viewed as composed of 16 subnets of /24 size that are
denoted as a1/24, a2/24, ..., a16/24. For example, a/20 is mostly at
ETR1, while only two of its subprefixes a8/24 and a15/24 are
elsewhere at ETR3 and ETR2, respectively (see Fig. 2 in the
document). From the point of view of efficiency of the mapping
distribution protocol, it may be beneficial for ETR1 to announce a
map for the entire space a/20 (rather than fragment it into a
multitude of more-specific prefixes), and provide the necessary
exceptions in the map information. Thus the map message could be in
the form of Map:(a/20, ETR1; Exceptions: a8/24, a15/24). In
addition, ETR2 and ETR3 announce the maps for a15/24 and a8/24,
respectively, and so the ILMs know where the exception EID addresses
are located. Now consider a host associated with ITR1 initiating a
packet destined for an address a7(1), which is in a7/24 that is not
in the exception portion of a/20. Now a question arises as to which
of the following approaches would be the best choice:
1. ILM-R provides the complete mapping information for a/20 to ITR1
including all maps for relevant exception subprefixes.
2. ILM-R provides only the directly relevant map to ITR1 which in
this case is (a/20, ETR1).
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In the first approach, the advantage is that ITR1 would have the
complete mapping for a/20 (including exception subnets), and it would
not have to generate queries for subsequent first packets that are
destined to any address in a/20, including a8/24 and a15/24.
However, the disadvantage is that if there is a significant number of
exception subprefixes, then the very first packet destined for a/20
will experience a long delay, and also the processors at ITR1 and
ILM-R can experience overload. In addition, the memory usage at ITR1
can be very inefficient as well. The advantage of the second
approach above is that the ILM-R does not overload resources at ITR1
both in terms of processing and memory usage but it needs an enhanced
map response in of the form Map:(a/20, ETR1, MS=1), where MS (more
specific) indicator is set to 1 to indicate to ITR1 that not all
subnets in a/20 map to ETR1. The key idea is that aggregation is
beneficial and subnet exceptions must be handled with additional
messages or indicators in the maps.
13.1.3. Management of Mapping Distribution for Scenarios with Hierarchy
of ETRs and Multihoming
Now we highlight another architectural concept related to mapping
management (please refer to Fig. 3 in the document). Here we
consider the possibility that ETRs may be organized in a hierarchical
manner. For instance ETR7 is higher in hierarchy relative to ETR1,
ETR2, and ETR3, and like-wise ETR8 is higher relative to ETR4, ETR5,
and ETR6. For instance, ETRs 1 through 3 can relegate the locator
role to ETR7 for their EID address space. In essence, they can allow
ETR7 to act as the locator for the delivery networks in their
purview. ETR7 keeps a local mapping table for mapping the
appropriate EID address space to specific ETRs that are
hierarchically associated with it in the level below. In this
situation, ETR7 can perform EID address space aggregation across ETRs
1 through 3 and can also include its own immediate EID address space
for the purpose of that aggregation. The many details related to
this approach and special circumstances involving multihoming of
subnets are discussed in detail in the detailed document noted
earlier. The hierarchical organization of ETRs and delivery networks
should help in the future growth and scalability of ETRs and mapping
distribution networks. This is essentially recursive map-and-encap,
and some of the mapping distribution and management functionality
will remain local to topologically neighboring delivery networks
which are hierarchically underneath ETRs.
13.1.4. References
[EEMDP Considerations] [EEMDP Presentation] [FIBAggregatability]
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13.2. Critique
This scheme [EEMDP Considerations] represents one approach to mapping
overhead reduction, and it is a general idea that is applicable to
any proposal that includes prefix or EID aggregation. A somewhat
similar idea is also used in Level-3 aggregation in the FIB
aggregation proposal. [FIBAggregatability] There can be cases where
deaggregation of EID prefixes occur in such a way that bulk of an EID
prefix P would be attached to one locator (say, ETR1) while a few
subprefixes under P would be attached to other locators elsewhere
(say, ETR2, ETR3, etc.). Ideally such cases should not happen,
however in reality it can happen as RIR's address allocations are
imperfect. In addition, as new IP address allocations become harder
to get, an IPv4 prefix owner might split previously unused
subprefixes of that prefix and allocate them to remote sites (homed
to other ETRs). Assuming these situations could arise in practice,
the nature of the solution would be that the response from the
mapping server for the coarser site would include information about
the more specifics. The solution as presented seems correct.
The proposal mentions that in Approach 1, the ID-Locator Mapping
(ILM) system provides the complete mapping information for an
aggregate EID prefix to a querying ITR including all the maps for the
relevant exception subprefixes. The sheer number of such more-
specifics can be worrisome, for example, in LISP. What if a
company's mobile-node EIDs came out of their corporate EID-prefix?
Approach 2 is far better but still there may be too many entries for
a regional ILM to store. In Approach 2, the ILM communicates that
there are more specifics but does not communicate their mask-length.
A suggested improvement would be that rather than saying that there
are more specifics, indicate what their mask-lengths are. There can
be multiple mask lengths. This number should be pretty small for For
IPv4 but can be large for IPv6.
Later in the proposal, a different problem is addressed involving a
hierarchy of ETRs and how aggregation of EID prefixes from lower
level ETRs can be performed at a higher level ETR. The various
scenarios here are well illustrated and described. This seems like a
good idea, and a solution like LISP can support this as specified.
As any optimization scheme would inevitably add some complexity; the
proposed scheme for enhancing mapping efficiency comes with some of
its own overhead. The gain depends on the details of specific EID
blocks, i.e., how frequently the situations arise such as an ETR
having a bigger EID block with a few holes.
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13.3. Rebuttal
There are two main points in the critique that would be addressed
here: (1) The gain depends on the details of specific EID blocks,
i.e., how frequently the situations arise such as an ETR having a
bigger EID block with a few holes, and (2) Approach 2 is lacking an
added feature of conveying just the mask-length of the more specifics
that exist as part of current map-response.
Regarding comment (1) above, there are multiple possibilities
regarding how situations can arise resulting in allocations having
holes in them. An example of one of these possibilities is as
follows. Org-A has historically received multiple /20s, /22s, /24s
over the course of time which are adjacent to each other. At the
present time, these prefixes would all aggregate to a /16 but for the
fact that just a few of the underlying /24s have been allocated
elsewhere historically to other organizations by an RIR or ISPs. An
example of a second possibility is that Org-A has an allocation of a
/16 prefix. It has suballocated a /22 to one of its subsidiaries,
and subsequently sold the subsidiary to another Org-B. For ease of
keeping the /22 subnet up and running without service disruption, the
/22 subprefix is allowed to be transferred in the acquisition
process. Now the /22 subprefix originates from a different AS and is
serviced by a different ETR (as compared to the parent \16 prefix).
We are in the process of performing an analysis of RIR allocation
data and are aware of other studies (notably at UCLA) which are also
performing similar analysis to quantify the frequency of occurrence
of the holes. We feel that the problem that has been addressed is a
realistic one, and the proposed scheme would help reduce the
overheads associated with the mapping distribution system.
Regarding comment (2) above, the suggested modification to Approach 2
would be definitely beneficial. In fact, we feel that it would be
fairly straight forward to dynamically use Approach 1 or Approach 2
(with the suggested modification), depending on whether there are
only a few (e.g., <=5) or many (e.g., >5) more specifics,
respectively. The suggested modification of notifying the mask-
length of the more specifics in map-response is indeed very helpful
because then the ITR would not have to resend a map-query for EID
addresses that match the EID address in the previous query up to at
least mask-length bit positions. There can be a two-bit field in
map-response that would indicate: (a) With value 00 for notifying
that there are no more-specifics; (b) With value 01 for notifying
that there are more-specifics and their exact information follows in
additional map-responses, and (c) With value 10 for notifying that
there are more-specifics and the mask-length of the next more-
specific is indicated in the current map-response. An additional
field will be included which will be used to specify the mask-length
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of the next more-specific in the case of the "10" indication (case
(c) above).
13.4. Counterpoint
No counterpoint was submitted for this proposal.
14. Evolution
14.1. Summary
As the Internet continues its rapid growth, router memory size and
CPU cycle requirements are outpacing feasible hardware upgrade
schedules. We propose to solve this problem by applying aggregation
with increasing scopes to gradually evolve the routing system towards
a scalable structure. At each evolutionary step, our solution is
able to interoperate with the existing system and provide immediate
benefits to adopters to enable deployment. This document summarizes
the need for an evolutionary design, the relationship between our
proposal and other revolutionary proposals and the steps of
aggregation with increasing scopes. Our detailed proposal can be
found in [I-D.zhang-evolution].
14.1.1. Need for Evolution
Multiple different views exist regarding the routing scalability
problem. Networks differ vastly in goals, behavior, and resources,
giving each a different view of the severity and imminence of the
scalability problem. Therefore we believe that, for any solution to
be adopted, it will start with one or a few early adopters, and may
not ever reach the entire Internet. The evolutionary approach
recognizes that changes to the Internet can only be a gradual process
with multiple stages. At each stage, adopters are driven by and
rewarded with solving an immediate problem. Each solution must be
deployable by individual networks who deem it necessary at a time
they deem it necessary, without requiring coordination from other
networks, and the solution has to bring immediate relief to a single
first-mover.
14.1.2. Relation to Other RRG Proposals
Most proposals take a revolutionary approach that expects the entire
Internet to eventually move to some new design whose main benefits
would not materialize until the vast majority of the system has been
upgraded; their incremental deployment plan simply ensures
interoperation between upgraded and legacy parts of the system. In
contrast, the evolutionary approach depicts a picture where changes
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may happen here and there as needed, but there is no dependency on
the system as a whole making a change. Whoever takes a step forward
gains the benefit by solving his own problem, without depending on
others to take actions. Thus, deployability includes not only
interoperability, but also the alignment of costs and gains.
The main differences between our approach and more revolutionary map-
and-encap proposals are: (a) we do not start with a pre-defined
boundary between edge and core; and (b) each step brings immediate
benefits to individual first-movers. Note that our proposal neither
interferes nor prevents any revolutionary host-based solutions such
as ILNP from being rolled out. However, host-based solutions do not
bring useful impact until a large portion of hosts have been
upgraded. Thus even if a host-based solution is rolled out in the
long run, an evolutionary solution is still needed for the near term.
14.1.3. Aggregation with Increasing Scopes
Aggregating many routing entries to a fewer number is a basic
approach to improving routing scalability. Aggregation can take
different forms and be done within different scopes. In our design,
the aggregation scope starts from a single router, then expands to a
single network, and neighbor networks. The order of the following
steps is not fixed but is merely a suggestion; it is under each
individual network's discretion which steps they choose to take based
on their evaluation of the severity of the problems and the
affordability of the solutions.
1. FIB Aggregation (FA) in a single router. A router
algorithmically aggregates its FIB entries without changing its
RIB or its routing announcements. No coordination among routers
is needed, nor any change to existing protocols. This brings
scalability relief to individual routers with only a software
upgrade.
2. Enabling 'best external' on PEs, ASBRs, and RRs, and turning on
next-hop-self on RRs. For hierarchical networks, the RRs in each
PoP can serve as a default gateway for nodes in the PoP, thus
allowing the non-RR nodes in each PoP to maintain smaller routing
tables that only include paths that egress out of that PoP. This
is known as 'topology-based mode' Virtual Aggregation, and can be
done with existing hardware and configuration changes only.
Please see [Evolution Grow Presentation] for details.
3. Virtual Aggregation (VA) in a single network. Within an AS, some
fraction of existing routers are designated as Aggregation Point
Routers (APRs). These routers are either individually or
collectively maintain the full FIB table. Other routers may
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suppress entries from their FIBs, instead forwarding packets to
APRs, which will then tunnel the packets to the correct egress
routers. VA can be viewed as an intra-domain map-and-encap
system to provide the operators with a control mechanism for the
FIB size in their routers.
4. VA across neighbor networks. When adjacent networks have VA
deployed, they can go one step further by piggybacking egress
router information on existing BGP announcements, so that packets
can be tunneled directly to a neighbor network's egress router.
This improves packet delivery performance by performing the
encapsulation/decapsulation only once across these neighbor
networks, as well as reducing the stretch of the path.
5. Reducing RIB Size by separating the control plane from the data
plane. Although a router's FIB can be reduced by FA or VA, it
usually still needs to maintain the full RIB to produce complete
routing announcements to its neighbors. To reduce the RIB size,
a network can set up special boxes, which we call controllers, to
take over the eBGP sessions from border routers. The controllers
receive eBGP announcements, make routing decisions, and then
inform other routers in the same network of how to forward
packets, while the regular routers just focus on the job of
forwarding packets. The controllers, not being part of the data
path, can be scaled using commodity hardware.
6. Insulating forwarding routers from routing churn. For routers
with a smaller RIB, the rate of routing churn is naturally
reduced. Further reduction can be achieved by not announcing
failures of customer prefixes into the core, but handling these
failures in a data-driven fashion, e.g., a link failure to an
edge network is not reported unless and until there are data
packets that are heading towards the failed link.
14.1.4. References
[I-D.zhang-evolution] [Evolution Grow Presentation]
14.2. Critique
All of the RRG proposals that scale the routing architecture share
one fundamental approach, route aggregation, in different forms,
e.g., LISP removes "edge prefixes" using encapsulation at ITRs, and
ILNP achieves the goal by locator rewrite. In this evolutionary path
proposal, each stage of the evolution applies aggregation with
increasing scopes to solve a specific scalability problem, and
eventually the path leads towards global routing scalability. For
example, it uses FIB aggregation at the single router level, virtual
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aggregation at the network level, and then between neighboring
networks at the inter-domain level.
Compared to other proposals, this proposal has the lowest hurdle to
deployment, because it does not require that all networks move to use
a global mapping system or upgrade all hosts, and it is designed for
each individual network to get immediate benefits after its own
deployment.
Criticisms of this proposal fall into two types. The first type
concerns several potential issues in the technical design as listed
below:
1. FIB aggregation, at level-3 and level-4, may introduce extra
routable space. Concerns have been raised about the potential
routing loops resulting from forwarding otherwise non-routable
packets, and the potential impact on RPF checking. These
concerns can be addressed by choosing a lower level of
aggregation and by adding null routes to minimize the extra
space, at the cost of reduced aggregation gain.
2. Virtual Aggregation changes the traffic paths in an ISP network,
thereby introducing stretch. Changing the traffic path may also
impact the reverse path checking practice used to filter out
packets from spoofed sources. More analysis is need to identify
the potential side-effects of VA and to address these issues.
3. The current Virtual Aggregation description is difficult to
understand, due to its multiple options for encapsulation and
popular prefix configurations, which makes the mechanism look
overly complicated. More thought is needed to simplify the
design and description.
4. FIB Aggregation and Virtual Aggregation may require additional
operational cost. There may be new design trade-offs that the
operators need to understand in order to select the best option
for their networks. More analysis is needed to identify and
quantify all potential operational costs.
5. In contrast to a number of other proposals, this solution does
not provide mobility support. It remains an open question as to
whether the routing system should handle mobility.
The second criticism is whether deploying quick fixes like FIB
aggregation would alleviate scalability problems in the short term
and reduce the incentives for deploying a new architecture; and
whether an evolutionary approach would end up with adding more and
more patches to the old architecture, and not lead to a fundamentally
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new architecture as the proposal had expected. Though this solution
may get rolled out more easily and quickly, a new architecture, if/
once deployed, could solve more problems with cleaner solutions.
14.3. Rebuttal
No rebuttal was submitted for this proposal.
14.4. Counterpoint
No counterpoint was submitted for this proposal.
15. Name-Based Sockets
15.1. Summary
Name-based sockets are an evolution of the existing address-based
sockets, enabling applications to initiate and receive communication
sessions based on the use of domain names in lieu of IP addresses.
Name-based sockets move the existing indirection from domain names to
IP addresses from its current position in applications down to the IP
layer. As a result, applications communicate exclusively based on
domain names, while the discovery, selection, and potentially in-
session re-selection of IP addresses is centrally performed by the IP
stack itself.
Name-based sockets help mitigate the Internet routing scalability
problem by separating naming and addressing more consistently than
what is possible with the existing address-based sockets. This
supports IP address aggregation because it simplifies the use of IP
addresses with high topological significance, as well as the dynamic
replacement of IP addresses during network-topological and host-
attachment changes.
A particularly positive effect of name-based sockets on Internet
routing scalability is the new incentives for edge network operators
to use provider-assigned IP addresses, which are more aggregatable
than the typically preferred provider-independent IP addresses. Even
though provider-independent IP addresses are harder to get and more
expensive than provider-assigned IP addresses, many operators desire
provider-independent addresses due to the high indirect cost of
provider-assigned IP addresses. This indirect cost is comprised of
both difficulties in multihoming, and tedious and largely manual
renumbering upon provider changes.
Name-based sockets reduce the indirect cost of provider-assigned IP
addresses in three ways, and hence make the use of provider-assigned
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IP addresses more acceptable: (1) They enable fine-grained and
responsive multihoming. (2) They simplify renumbering by offering an
easy means to replace IP addresses in referrals with domain names.
This helps avoiding updates to application and operating system
configurations, scripts, and databases during renumbering. (3) They
facilitate low-cost solutions that eliminate renumbering altogether.
One such low-cost solution is IP address translation, which in
combination with name-based sockets loses its adverse impact on
applications.
The prerequisite for a positive effect of name-based sockets on
Internet routing scalability is their adoption in operating systems
and applications. Operating systems should be augmented to offer
name-based sockets as a new alternative to the existing address-based
sockets, and applications should use name-based sockets for their
communications. Neither an instantaneous, nor an eventually complete
transition to name-based sockets is required, yet the positive effect
on Internet routing scalability will grow with the extent of this
transition.
Name-based sockets were hence designed with a focus on deployment
incentives, comprising both immediate deployment benefits as well as
low deployment costs. Name-based sockets provide a benefit to
application developers because the alleviation of applications from
IP address management responsibilities simplifies and expedites
application development. This benefit is immediate owing to the
backwards compatibility of name-based sockets with legacy
applications and legacy peers. The appeal to application developers,
in turn, is an immediate benefit for operating system vendors who
adopt name-based sockets.
Name-based sockets furthermore minimize deployment costs: Alternative
techniques to separate naming and addressing provide applications
with "surrogate IP addresses" that dynamically map onto regular IP
addresses. A surrogate IP address is indistinguishable from a
regular IP address for applications, but does not have the
topological significance of a regular IP address. Mobile IP and the
Host Identity Protocol are examples of such separation techniques.
Mobile IP uses "home IP addresses" as surrogate IP addresses with
reduced topological significance. The Host Identity Protocol uses
"host identifiers" as surrogate IP addresses without topological
significance. A disadvantage of surrogate IP addresses is their
incurred cost in terms of extra administrative overhead and, for some
techniques, extra infrastructure. Since surrogate IP addresses must
be resolvable to the corresponding regular IP addresses, they must be
provisioned in the DNS or similar infrastructure. Mobile IP uses a
new infrastructure of home agents for this purpose, while the Host
Identity Protocol populates DNS servers with host identities. Name-
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based sockets avoid this cost because they function without surrogate
IP addresses, and hence without the provisioning and infrastructure
requirements that accompany surrogate addresses.
Certainly, some edge networks will continue to use provider-
independent addresses despite name-based sockets, perhaps simply due
to inertia. But name-based sockets will help reduce the number of
those networks, and thus have a positive impact on Internet routing
scalability.
A more comprehensive description of name-based sockets can be found
in [Name Based Sockets].
15.1.1. References
[Name Based Sockets]
15.2. Critique
Name-based sockets contribution to the routing scalability problem is
to decrease the reliance on PI addresses, allowing a greater use of
PA addresses, and thus a less fragmented routing table. It provides
end hosts with an API which makes the applications address-agnostic.
The name abstraction allows the hosts to use any type of locator,
independent of format or provider. This increases the motivation and
usability of PA addresses. Some applications, in particular
bootstrapping applications, may still require hard coded IP
addresses, and as such will still motivate the use of PI addresses.
15.2.1. Deployment
The main incentives and drivers are geared towards the transition of
applications to the name-based sockets. Adoption by applications
will be driven by benefits in terms of reduced application
development cost. Legacy applications are expected to migrate to the
new API at a slower pace, as the name-based sockets are backwards
compatible, this can happen in a per-host fashion. Also, not all
applications can be ported to a FQDN dependent infrastructure, e.g.
DNS functions. This hurdle is manageable, and may not be a definite
obstacle for the transition of a whole domain, but it needs to be
taken into account when striving for mobility/multihoming of an
entire site. The transition of functions on individual hosts may be
trivial, either through upgrades/changes to the OS or as linked
libraries. This can still happen incrementally and independently, as
compatibility is not affected by the use of name-based sockets.
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15.2.2. Edge-networks
Name-based sockets rely on the transition of individual applications
and are backwards compatible, so they do not require bilateral
upgrades. This allows each host to migrate its applications
independently. Name-based sockets may make an individual client
agnostic to the networking medium, be it PA/PI IP-addresses or in a
the future an entirely different networking medium. However, an
entire edge-network, with internal and external services will not be
able to make a complete transition in the near future. Hence, even
if a substantial fraction of the hosts in an edge-network use name-
based sockets, PI addresses may still be required by the edge-
network. In short, new services may be implemented using name-based
sockets, old services may be ported. Name-based sockets provide an
increased motivation to move to PA-addresses as actual provider
independence relies less and less on PI-addressing.
15.3. Rebuttal
No rebuttal was submitted for this proposal.
15.4. Counterpoint
No counterpoint was submitted for this proposal.
16. Routing and Addressing in Networks with Global Enterprise Recursion
(IRON-RANGER)
16.1. Summary
RANGER is a locator-identifier separation approach that uses IP-in-IP
encapsulation to connect edge networks across transit networks such
as the global Internet. End systems use endpoint interface
identifier (EID) addresses that may be routable within edge networks
but do not appear in transit network routing tables. EID to Routing
Locator (RLOC) address bindings are instead maintained in mapping
tables and also cached in default router FIBs (i.e., very much the
same as for the global DNS and its associated caching resolvers).
RANGER enterprise networks are organized in a recursive hierarchy
with default mappers connecting lower layers to the next higher layer
in the hierarchy. Default mappers forward initial packets and push
mapping information to lower-tier routers and end systems through
secure redirection.
RANGER is an architectural framework derived from the Intra-Site
Automatic Tunnel Addressing Protocol (ISATAP).
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16.1.1. Gains
o provides a scalable routing system alternative in instances where
dynamic routing protocols are impractical
o naturally supports a recursively-nested "network-of-networks" (or,
"enterprise-within-enterprise") hierarchy
o uses asymmetric security mechanisms (i.e., secure neighbor
discovery) to secure router discovery and the redirection
mechanism
o can quickly detect path failures and pick alternate routes
o naturally supports provider-independent addressing
o support for site multihoming and traffic engineering
o ingress filtering for multihomed sites
o mobility-agile through explicit cache invalidation (much more
reactive than DynDns)
o supports neighbor discovery and neighbor unreachability detection
over tunnels
o no changes to end systems
o no changes to most routers
o supports IPv6 transition
o compatible with true identity/locator split mechanisms such as HIP
(i.e., packets contain a HIP Host Identity Tag (HIT) as an end
system identifier, IPv6 address as endpoint Interface iDentifier
(EID) in the inner IP header and IPv4 address as Routing LOCator
(RLOC) in the outer IP header)
o prototype code available
16.1.2. Costs
o new code needed in enterprise border routers
o locator/path liveness detection using RFC4861 neighbor
unreachability detection (i.e., extra control messages, but data-
driven)
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16.1.3. References
[I-D.templin-iron] [I-D.russert-rangers] [I-D.templin-intarea-vet]
[I-D.templin-intarea-seal] [RFC5201] [RFC5214] [RFC5720]
16.2. Critique
The RANGER architectural framework is intended to be applicable for a
Core-Edge Separation (CES) architecture for scalable routing, using
either IPv4 or IPv6 - or using both in an integrated system which may
carry one protocol over the other.
However, despite the ID being readied for publication as an
experimental RFC, the framework falls well short of the level of
detail required to envisage how it could be used to implement a
practical scalable routing solution. For instance, the ID contains
no specification for a mapping protocol, or how the mapping lookup
system would work on a global scale.
There is no provision for RANGER's ITR-like routers being able to
probe the reachability of end-user networks via multiple ETR-like
routers - nor for any other approach to multihoming service
restoration.
Nor is there any provision for inbound TE or support of mobile
devices which frequently change their point of attachment.
Therefore, in its current form, RANGER cannot be contemplated as a
superior scalable routing solution to some other proposals which are
specified in sufficient detail and which appear to be feasible.
RANGER uses its own tunneling and PMTUD management protocol: SEAL.
Adoption of SEAL in its current form would prevent the proper
utilization of jumbo frame paths in the DFZ, which will become the
norm in the future. SEAL uses RFC 1191 PTB messages to the sending
host only to fix a preset maximum packet length. To avoid the need
for the SEAL layer to fragment packets of this length, this MTU value
(for the input of the tunnel) needs to be set significantly below
1500 bytes, assuming the typically ~1500 byte MTU values for paths
across the DFZ today. In order to avoid this excessive
fragmentation, this value could only be raised to a ~9k byte value at
some time in the future where essentially all paths between ITRs and
ETRs were jumbo frame capable.
16.3. Rebuttal
The Internet Routing Overlay Network (IRON) [I-D.templin-iron] is a
scalable Internet routing architecture that builds on the RANGER
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recursive enterprise network hierarchy [RFC5720]. IRON bonds
together participating RANGER networks using VET
[I-D.templin-intarea-vet] and SEAL [I-D.templin-intarea-seal] to
enable secure and scalable routing through automatic tunneling within
the Internet core. The IRON-RANGER automatic tunneling abstraction
views the entire global Internet DFZ as a virtual NBMA link similar
to ISATAP [RFC5214].
IRON-RANGER is an example of a Core-Edge Separation (CES) system.
Instead of a classical mapping database, however, IRON-RANGER uses a
hybrid combination of a proactive dynamic routing protocol for
distributing highly aggregated Virtual Prefixes (VPs) and an on-
demand data driven protocol for distributing more-specific Provider
Independent (PI) prefixes derived from the VPs.
The IRON-RANGER hierarchy consists of recursively-nested RANGER
enterprise networks joined together by IRON routers that participate
in a global BGP instance. The IRON BGP instance is maintained
separately from the current Internet BGP Routing LOCator (RLOC)
address space (i.e., the set of all public IPv4 prefixes in the
Internet). Instead, the IRON BGP instance maintains VPs taken from
Endpoint Interface iDentifier (EID) address space, e.g., the IPv6
global unicast address space. To accommodate scaling, only O(10k) -
O(100k) VPs are allocated e.g., using /20 or shorter IPv6 prefixes.
IRON routers lease portions of their VPs as Provider Independent (PI)
prefixes for customer equipment (CEs), thereby creating a sustainable
business model. CEs that lease PI prefixes propagate address
mapping(s) throughout their attached RANGER networks and up to VP-
owning IRON router(s) through periodic transmission of "bubbles" with
authentication and PI prefix information. Routers in RANGER networks
and IRON routers that receive and forward the bubbles securely
install PI prefixes in their FIBs, but do not inject them into the
RIB. IRON routers therefore keep track of only their customer base
via the FIB entries and keep track of only the Internet-wide VP
database in the RIB.
IRON routers propagate more-specific prefixes using secure
redirection to update router FIBs. Prefix redirection is driven by
the data plane and does not affect the control plane. Redirected
prefixes are not injected into the RIB, but rather are maintained as
FIB soft state that is purged after expiration or route failure.
Neighbor unreachability detection is used to detect failure.
Secure prefix registrations and redirections are accommodated through
the mechanisms of SEAL. Tunnel endpoints using SEAL synchronize
sequence numbers, and can therefore discard any packets they receive
that are outside of the current sequence number window. Hence, off-
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path attacks are defeated. These synchronized tunnel endpoints can
therefore exchange prefixes with signed certificates that prove
prefix ownership in such a way that DoS vectors that attack crypto
calculation overhead are eliminated due to the prevention of off-path
attacks.
CEs can move from old RANGER networks and re-inject their PI prefixes
into new RANGER networks. This would be accommodated by IRON-RANGER
as a site multihoming event while host mobility and true locator-ID
separation is accommodated via HIP [RFC5201].
16.4. Counterpoint
No counterpoint was submitted for this proposal.
17. Recommendation
As can be seen from the extensive list of proposals above, the group
explored a number of possible solutions. Unfortunately, the group
did not reach rough consensus on a single best approach.
Accordingly, the recommendation has been left to the co-chairs. The
remainder of this section describes the rationale and decision of the
co-chairs.
As a reminder, the goal of the research group was to develop a
recommendation for an approach to a routing and addressing
architecture for the Internet. The primary goal of the architecture
is to provide improved scalability for the routing subsystem.
Specifically, this implies that we should be able to continue to grow
the routing subsystem to meet the needs of the Internet without
requiring drastic and continuous increases in the amount of state or
processing requirements for routers.
17.1. Motivation
There is a general concern that the cost and structure of the routing
and addressing architecture as we know it today may become
prohibitively expensive with continued growth, with repercussions to
the health of the Internet. As such, there is an urgent need to
examine and evaluate potential scalability enhancements.
For the long term future of the Internet, it has become apparent that
IPv6 is going to play a significant role. It has taken more than a
decade, but IPv6 is starting to see some non-trivial amount of
deployment. This is in part due to the depletion of IPv4 addresses.
It therefore seems apparent that the new architecture must be
applicable to IPv6. It may or may not be applicable to IPv4, but not
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addressing the IPv6 portion of the network would simply lead to
recreating the routing scalability problem in the IPv6 domain,
because the two share a common routing architecture.
Whatever change we make, we should expect that this is a very long-
lived change. The routing architecture of the entire Internet is a
loosely coordinated, complex, expensive subsystem, and permanent,
pervasive changes to it will require difficult choices during
deployment and integration. These cannot be undertaken lightly.
By extension, if we are going to the trouble, pain, and expense of
making major architectural changes, it follows that we want to make
the best changes possible. We should regard any such changes as
permanent and we should therefore aim for long term solutions that
place the network in the best possible position for ongoing growth.
These changes should be cleanly integrated, first-class citizens
within the architecture. That is to say that any new elements that
are integrated into the architecture should be fundamental
primitives, on par with the other existing legacy primitives in the
architecture, that interact naturally and logically when in
combination with other elements of the architecture.
Over the history of the Internet, we have been very good about
creating temporary, ad-hoc changes, both to the routing architecture
and other aspects of the network layer. However, many of these band-
aid solutions have come with a significant overhead in terms of long-
term maintenance and architectural complexity. This is to be avoided
and short-term improvements should eventually be replaced by long-
term, permanent solutions.
In the particular instance of the routing and addressing architecture
today, we feel that the situation requires that we pursue both short-
term improvements and long-term solutions. These are not
incompatible because we truly intend for the short-term improvements
to be completely localized and temporary. The short-term
improvements are necessary to give us the time necessary to develop,
test, and deploy the long-term solution. As the long-term solution
is rolled out and gains traction, the short-term improvements should
be of less benefit and can subsequently be withdrawn.
17.2. Recommendation to the IETF
The group explored a number of proposed solutions but did not reach
consensus on a single best approach. Therefore, in fulfillment of
the routing research group's charter, the co-chairs recommend that
the IETF pursue work in the following areas:
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Aggregation in Increasing Scopes [I-D.zhang-evolution]
Identifier/Locator Network Protocol (ILNP) [ILNP Site]
Renumbering [RFC5887]
17.3. Rationale
We selected Aggregation in Increasing Scopes because it is a short-
term improvement. It can be applied on a per-domain basis, under
local administration and has immediate effect. While there is some
complexity involved, we feel that this option is constructive for
service providers who find the additional complexity to be less
painful than upgrading hardware. This improvement can be deployed by
domains that feel it necessary, for as long as they feel it is
necessary. If this deployment lasts longer than expected, then the
implications of that decision are wholly local to the domain.
We recommended ILNP because we find it to be a clean solution for the
architecture. It separates location from identity in a clear,
straightforward way that is consistent with the remainder of the
Internet architecture and makes both first-class citizens. Unlike
the many map-and-encap proposals, there are no complications due to
tunneling, indirection, or semantics that shift over the lifetime of
a packets delivery.
We recommend further work on automating renumbering because even with
ILNP, the ability of a domain to change its locators at minimal cost
is fundamentally necessary. No routing architecture will be able to
scale without some form of abstraction, and domains that change their
point of attachment must fundamentally be prepared to change their
locators in line with this abstraction. We recognize that [RFC5887]
is not a solution so much as a problem statement, and we are simply
recommending that the IETF create effective and convenient mechanisms
for site renumbering.
18. Acknowledgments
This document represents a small portion of the overall work product
of the Routing Research Group, who have developed all of these
architectural approaches and many specific proposals within this
solution space.
19. IANA Considerations
This memo includes no requests to IANA.
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20. Security Considerations
All solutions are required to provide security that is at least as
strong as the existing Internet routing and addressing architecture.
21. References
21.1. Normative References
[I-D.irtf-rrg-design-goals]
Li, T., "Design Goals for Scalable Internet Routing",
draft-irtf-rrg-design-goals-01 (work in progress),
July 2007.
[I-D.narten-radir-problem-statement]
Narten, T., "On the Scalability of Internet Routing",
draft-narten-radir-problem-statement-05 (work in
progress), February 2010.
21.2. Informative References
[CRM] Flinck, H., "Compact routing in locator identifier mapping
system", <http://www.tschofenig.priv.at/rrg/
CR_mapping_system_0.1.pdf>.
[DNSnBIND]
Liu, C. and P. Albitz, "DNS & BIND", 2006.
5th Edition, O'Reilly & Associates, Sebastopol, CA, USA.
ISBN 0-596-10057-4
[EEMDP Considerations]
Sriram, K., Kim, Y., and D. Montgomery, "Architectural
Considerations for Mapping Distribution Protocols",
<http://www.antd.nist.gov/~ksriram/NGRA_map_mgmt.pdf>.
[EEMDP Presentation]
Sriram, K., Kim, Y., and D. Montgomery, "Architectural
Considerations for Mapping Distribution Protocols", <http:
//www.antd.nist.gov/~ksriram/MDP_Dublin_KS_Slides.pdf>.
[Evolution Grow Presentation]
Francis, P., Xu, X., Ballani, H., Jen, D., Raszuk, R., and
L. Zhang, "Virtual Aggregation (VA)",
<http://tools.ietf.org/agenda/76/slides/grow-5.pdf>.
[FIBAggregatability]
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Zhang, B., Wang, L., Zhao, X., Liu, Y., and L. Zhang, "An
Evaluation Study of Router FIB Aggregatability",
<http://www.ietf.org/proceedings/76/slides/grow-2.pdf>.
[GLI] Menth, M., Hartmann, M., and D. Klein, "Global Locator,
Local Locator, and Identifier Split (GLI-Split)", <http://
www3.informatik.uni-wuerzburg.de/~menth/Publications/
papers/Menth-GLI-Split.pdf>.
[I-D.adan-idr-tidr]
Adan, J., "Tunneled Inter-domain Routing (TIDR)",
draft-adan-idr-tidr-01 (work in progress), December 2006.
[I-D.carpenter-behave-referral-object]
Carpenter, B., Boucadair, M., Halpern, J., Jiang, S., and
K. Moore, "A Generic Referral Object for Internet
Entities", draft-carpenter-behave-referral-object-01 (work
in progress), October 2009.
[I-D.farinacci-lisp-lig]
Farinacci, D. and D. Meyer, "LISP Internet Groper (LIG)",
draft-farinacci-lisp-lig-02 (work in progress),
February 2010.
[I-D.frejborg-hipv4]
Frejborg, P., "Hierarchical IPv4 Framework",
draft-frejborg-hipv4-07 (work in progress), July 2010.
[I-D.ietf-lisp]
Farinacci, D., Fuller, V., Meyer, D., and D. Lewis,
"Locator/ID Separation Protocol (LISP)",
draft-ietf-lisp-08 (work in progress), August 2010.
[I-D.ietf-lisp-alt]
Fuller, V., Farinacci, D., Meyer, D., and D. Lewis, "LISP
Alternative Topology (LISP+ALT)", draft-ietf-lisp-alt-04
(work in progress), April 2010.
[I-D.ietf-lisp-interworking]
Lewis, D., Meyer, D., Farinacci, D., and V. Fuller,
"Interworking LISP with IPv4 and IPv6",
draft-ietf-lisp-interworking-00 (work in progress),
May 2009.
[I-D.ietf-lisp-ms]
Fuller, V. and D. Farinacci, "LISP Map Server",
draft-ietf-lisp-ms-05 (work in progress), April 2010.
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[I-D.meyer-lisp-mn]
Farinacci, D., Fuller, V., Lewis, D., and D. Meyer, "LISP
Mobile Node", draft-meyer-lisp-mn-03 (work in progress),
August 2010.
[I-D.meyer-loc-id-implications]
Meyer, D. and D. Lewis, "Architectural Implications of
Locator/ID Separation", draft-meyer-loc-id-implications-01
(work in progress), January 2009.
[I-D.rja-ilnp-nonce]
Atkinson, R., "Nonce Destination Option",
draft-rja-ilnp-nonce-04 (work in progress), June 2010.
[I-D.russert-rangers]
Russert, S., Fleischman, E., and F. Templin, "RANGER
Scenarios", draft-russert-rangers-05 (work in progress),
July 2010.
[I-D.templin-intarea-seal]
Templin, F., "The Subnetwork Encapsulation and Adaptation
Layer (SEAL)", draft-templin-intarea-seal-16 (work in
progress), July 2010.
[I-D.templin-intarea-vet]
Templin, F., "Virtual Enterprise Traversal (VET)",
draft-templin-intarea-vet-16 (work in progress),
July 2010.
[I-D.templin-iron]
Templin, F., "The Internet Routing Overlay Network
(IRON)", draft-templin-iron-10 (work in progress),
August 2010.
[I-D.whittle-ivip-drtm]
Whittle, R., "DRTM - Distributed Real Time Mapping for
Ivip and LISP", draft-whittle-ivip-drtm-01 (work in
progress), March 2010.
[I-D.whittle-ivip-glossary]
Whittle, R., "Glossary of some Ivip and scalable routing
terms", draft-whittle-ivip-glossary-01 (work in progress),
March 2010.
[I-D.whittle-ivip4-etr-addr-forw]
Whittle, R., "Ivip4 ETR Address Forwarding",
draft-whittle-ivip4-etr-addr-forw-02 (work in progress),
January 2010.
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[I-D.xu-rangi]
Xu, X., "Routing Architecture for the Next Generation
Internet (RANGI)", draft-xu-rangi-04 (work in progress),
August 2010.
[I-D.xu-rangi-proxy]
Xu, X., "Transition Mechanisms for Routing Architecture
for the Next Generation Internet (RANGI)",
draft-xu-rangi-proxy-01 (work in progress), July 2009.
[I-D.zhang-evolution]
Zhang, B. and L. Zhang, "Evolution Towards Global Routing
Scalability", draft-zhang-evolution-02 (work in progress),
October 2009.
[ILNP Site]
Atkinson, R., Bhatti, S., Hailes, S., Rehunathan, D., and
M. Lad, "ILNP - Identifier/Locator Network Protocol",
<http://ilnp.cs.st-andrews.ac.uk>.
[Ivip Constraints]
Whittle, R., "List of constraints on a successful scalable
routing solution which result from the need for widespread
voluntary adoption",
<http://www.firstpr.com.au/ip/ivip/RRG-2009/constraints/>.
[Ivip Mobility]
Whittle, R., "TTR Mobility Extensions for Core-Edge
Separation Solutions to the Internet's Routing Scaling
Problem",
<http://www.firstpr.com.au/ip/ivip/TTR-Mobility.pdf>.
[Ivip PMTUD]
Whittle, R., "IPTM - Ivip's approach to solving the
problems with encapsulation overhead, MTU, fragmentation
and Path MTU Discovery",
<http://www.firstpr.com.au/ip/ivip/pmtud-frag/>.
[Ivip6] Whittle, R., "Ivip6 - instead of map-and-encap, use the 20
bit Flow Label as a Forwarding Label",
<http://www.firstpr.com.au/ip/ivip/ivip6/>.
[LMS] Letong, S., Xia, Y., ZhiLiang, W., and W. Jianping, "A
Layered Mapping System For Scalable Routing", <http://
docs.google.com/
fileview?id=0BwsJc7A4NTgeOTYzMjFlOGEtYzA4OC00NTM0LTg5ZjktN
mFkYzBhNWJhMWEy&hl=en>.
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[LMS Summary]
Sun, C., "A Layered Mapping System (Summary)", <http://
docs.google.com/
Doc?docid=0AQsJc7A4NTgeZGM3Y3o1NzVfNmd3eGRzNGhi&hl=en>.
[MILCOM1] Atkinson, R. and S. Bhatti, "Site-Controlled Secure Multi-
homing and Traffic Engineering for IP", IEEE Military
Communications Conference (MILCOM) 28, Boston, MA, USA,
October 2009.
[MILCOM2] Atkinson, R., Bhatti, S., and S. Hailes, "Harmonised
Resilience, Multi-homing and Mobility Capability for IP",
IEEE Military Communications Conference (MILCOM) 27, San
Diego, CA, USA, November 2008.
[MobiArch1]
Atkinson, R., Bhatti, S., and S. Hailes, "Mobility as an
Integrated Service through the Use of Naming", ACM
International Workshop on Mobility in the Evolving
Internet (MobiArch) 2, Kyoto, Japan, August 2007.
[MobiArch2]
Atkinson, R., Bhatti, S., and S. Hailes, "Mobility Through
Naming: Impact on DNS", ACM International Workshop on
Mobility in the Evolving Internet (MobiArch) 3, Seattle,
USA, August 2008.
[Name Based Sockets]
Vogt, C., "Simplifying Internet Applications Development
With A Name-Based Sockets Interface", <http://
christianvogt.mailup.net/pub/
vogt-2009-name-based-sockets.pdf>.
[RANGI] Xu, X., "Routing Architecture for the Next-Generation
Internet (RANGI)",
<http://www.ietf.org/proceedings/09nov/slides/RRG-1.ppt>.
[RFC3007] Wellington, B., "Secure Domain Name System (DNS) Dynamic
Update", RFC 3007, November 2000.
[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "DNS Security Introduction and Requirements",
RFC 4033, March 2005.
[RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Resource Records for the DNS Security Extensions",
RFC 4034, March 2005.
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[RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Protocol Modifications for the DNS Security
Extensions", RFC 4035, March 2005.
[RFC4423] Moskowitz, R. and P. Nikander, "Host Identity Protocol
(HIP) Architecture", RFC 4423, May 2006.
[RFC5201] Moskowitz, R., Nikander, P., Jokela, P., and T. Henderson,
"Host Identity Protocol", RFC 5201, April 2008.
[RFC5214] Templin, F., Gleeson, T., and D. Thaler, "Intra-Site
Automatic Tunnel Addressing Protocol (ISATAP)", RFC 5214,
March 2008.
[RFC5534] Arkko, J. and I. van Beijnum, "Failure Detection and
Locator Pair Exploration Protocol for IPv6 Multihoming",
RFC 5534, June 2009.
[RFC5720] Templin, F., "Routing and Addressing in Networks with
Global Enterprise Recursion (RANGER)", RFC 5720,
February 2010.
[RFC5887] Carpenter, B., Atkinson, R., and H. Flinck, "Renumbering
Still Needs Work", RFC 5887, May 2010.
[RFC5902] Thaler, D., Zhang, L., and G. Lebovitz, "IAB Thoughts on
IPv6 Network Address Translation", RFC 5902, July 2010.
[TIDR AS forwarding]
Adan, J., "yetAnotherProposal: AS-number forwarding",
<http://www.ops.ietf.org/lists/rrg/2008/msg00716.html>.
[TIDR and LISP]
Adan, J., "LISP etc architecture",
<http://www.ops.ietf.org/lists/rrg/2007/msg00902.html>.
[TIDR identifiers]
Adan, J., "TIDR using the IDENTIFIERS attribute", <http://
www.ietf.org/mail-archive/web/ram/current/msg01308.html>.
[Valiant] Zhang-Shen, R. and N. McKeown, "Designing a Predictable
Internet Backbone Network", <http://
tiny-tera.stanford.edu/~nickm/papers/HotNetsIII.pdf>.
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Author's Address
Tony Li (editor)
Cisco Systems
170 West Tasman Dr.
San Jose, CA 95134
USA
Phone: +1 408 853 9317
Email: tony.li@tony.li
Li Expires February 18, 2011 [Page 73]