Internet Draft RJ Atkinson
draft-irtf-rrg-ilnp-arch-00.txt Consultant
Expires: 09 JUL 2012 SN Bhatti
Category: Experimental U. St Andrews
9 January 2012
ILNP Architectural Description
draft-irtf-rrg-ilnp-arch-00.txt
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Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six
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documents at any time. It is inappropriate to use Internet-Drafts
as reference material or to cite them other than as "work in
progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at
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This document is not on the IETF standards-track and does not
specify any level of standard. This document merely provides
information for the Internet community.
This document is part of the ILNP document set, which has had
extensive review within the IRTF Routing Research Group. ILNP
is one of the recommendations made by the RG Chairs. Separately,
various refereed research papers on ILNP have also been published
during this decade. So the ideas contained herein have had much
broader review than the IRTF Routing RG. The views in this
document were considered controversial by the Routing RG, but the
RG reached a consensus that the document still should be
published. The Routing RG has had remarkably little consensus on
anything, so virtually all Routing RG outputs are considered
controversial.
Abstract
This document provides an Architectural description and the
Concept of Operations for the Identifier-Locator Network Protocol
(ILNP), which is an experimental, evolutionary enhancement to
IP. This is a product of the IRTF Routing RG.
Table of Contents
1. Introduction .........................................?
2. Architectural Overview................................?
3. Architectural Changes Introduced by ILNP..............?
4. ILNP Basic Connectivity...............................?
5. Multi-Homing & Multi-Path Transport...................?
6. Mobility..............................................?
7. IP Security with ILNP.................................?
8. Backwards Compatibility & Incremental Deployment......?
9. Security Considerations ..............................?
10. Privacy Considerations................................?
11. IANA Considerations ..................................?
12. References ...........................................?
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1. INTRODUCTION
At present, the Internet research and development community are
exploring various approaches to evolving the Internet
Architecture to solve a variety of issues including, but not
limited to, scalability of inter-domain routing [RFC4984]. A wide
range of other issues (e.g. site multi-homing, node multi-homing,
site/subnet mobility, node mobility) are also active concerns at
present. Several different classes of evolution are being
considered by the Internet research & development community. One
class is often called "Map and Encapsulate", where traffic would
be mapped and then tunnelled through the inter-domain core of the
Internet. Another class being considered is sometimes known as
"Identifier/Locator Split". This document relates to a proposal
that is in the latter class of evolutionary approaches.
There has been substantial research relating to naming in the
Internet through the years [IEN1] [IEN19] [IEN23] [IEN31]
[RFC814] [RFC1498] [RFC2956]. Much of that research has indicated
that binding end-to-end session state with a specific interface
of a node at a specific location is undesirable, for example
creating avoidable issues for mobility, multi-homing, end-to-end
security. More recently, mindful of that important prior work,
and starting well before the Routing RG was re-chartered to focus
on inter-domain routing scalability, the authors have been
examining enhancements to certain naming aspects of the Internet
Architecture.
Our ideas and progress so far are embodied in the on-going
definition of an experimental protocol which we call the
Identifier Locator Network Protocol (ILNP). Links to
relevant material are all available at:
http://ilnp.cs.st-andrews.ac.uk/
In this document, we:
a) describe the architectural concepts behind ILNP and
how various ILNP capabilities operate: this document
deliberately focuses on describing the key architectural
changes that ILNP introduces and defers engineering
discussion to separate documents.
Other documents (listed below):
b) show how functions based on ILNP would be realised on
today's Internet by proposing an instance of ILNP based
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on IPv6, which we call ILNPv6 (there is also a document
describing ILNPv4, which is how ILNP could be applied
to IPv4).
c) discuss salient operational and engineering issues impacting
the deployment of ILNPv6 and the impact on the Internet.
d) give architectural descriptions of optional advanced
capabilities in advanced deployments based on the ILNP
approach.
1.1 Document Roadmap
This document describes the architecture for the Identifier
Locator Network Protocol (ILNP). The authors recommend reading
and understanding this document as the starting point to
understanding ILNP.
However, the ILNP architecture can have more than one engineering
instantiation. For example, one can imagine a "clean-slate"
engineering design based on the ILNP architecture. In separate
documents, we describe two specific engineering instances of
ILNP. The term ILNPv6 refers precisely to an instance of ILNP
that is based upon, and backwards compatible with, IPv6. The
term ILNPv4 refers precisely to an instance of ILNP that is
based upon, and backwards compatible with, IPv4.
Many engineering aspects common to both ILNPv4 and ILNPv6 are
described in [ILNP-ENG]. A full engineering specification for
either ILNPv6 or ILNPv4 is beyond the scope of this document.
Readers are referred to other related ILNP documents for details
not described here:
a) [ILNP-ENG] describes engineering and implementation
considerations that are common to both ILNPv4 and ILNPv6.
b) [ILNP-DNS] defines additional DNS resource records that
support ILNP.
b) [ILNP-ICMPv6] defines a new ICMPv6 Locator Update message
used by an ILNP node to inform its correspondent nodes
of any changes to its set of valid Locators.
c) [ILNP-NONCE6] defines a new IPv6 Nonce Destination Option
used by ILNPv6 nodes (1) to indicate to ILNP correspondent
nodes (by inclusion within the initial packets of an ILNP
session) that the node is operating in the ILNP mode and
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(2) to prevent off-path attacks against ILNP ICMP messages.
This Nonce is used, for example, with all ILNP ICMPv6
Locator Update messages that are exchanged among ILNP
correspondent nodes.
d) [ILNP-ICMPv4] defines a new ICMPv4 Locator Update message
used by an ILNP node to inform its correspondent nodes
of any changes to its set of valid Locators.
e) [ILNP-v4opts] defines a new IPv4 Nonce Option used by ILNPv4
nodes to carry a security nonce to prevent off-path attacks
against ILNP ICMP messages and also defines a new IPv4
Identifier Option used by ILNPv4 nodes.
1.2 History
In 1977, Internet researchers at University College London wrote
the first Internet Experiment Note (IEN), which discussed issues
with the interconnection of networks. That document identified
the inclusion of network-layer addresses in the transport-layer
session state (e.g. TCP checksum) as a significant problem for
mobile and multi-homed nodes and networks. It also proposed
separation of identity from location as a better approach to take
when designing the TCP/IP protocol suite. Unfortunately, that
separation did not occur, so the deployed IPv4 and IPv6 Internet
entangles upper-layer protocols (e.g. TCP, UDP) with
network-layer routing and topology information (e.g. IP
addresses) [IEN1].
The architectural concept behind ILNP derives from a June 1994
note by Bob Smart to the IETF SIPP WG mailing list [SIPP94]. In
January 1995, Dave Clark sent a similar note to the IETF IPng WG
mailing list, suggesting that the IPv6 address be split into
separate Identifier and Locator fields [IPng95].
Afterwards, Mike O'Dell pursued this concept in Internet-Drafts
describing "8+8" or "GSE" [8+8] [GSE]. More recently, the IRTF
Namespace Research Group (NSRG) studied this matter around the
turn of the century. Unusually for an IRTF RG, the NSRG operated
on the principle that unanimity was required for the NSRG to make
a recommendation. Atkinson was a member of the IRTF NSRG. At
least one other protocol, the Host Identity Protocol (HIP), also
derives in part from the IRTF NSRG studies (and related
antecedent work). This current proposal differs from O'Dell's
work in various ways, notably in that it does not require
deployment or use of Locator rewriting.
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The key idea proposed for ILNP is to directly and specifically
change the overloaded semantics of the IP address. The Internet
community has indicated explicitly, several times, that this use
of overloaded semantics is a significant problem with the use of
the Internet protocol today [RFC1498] [RFC2101] [RFC2956]
[RFC4984].
While the research community has made a number of proposals that
could provide solutions, so far there has been little progress on
changing the status quo.
1.3 Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. ARCHITECTURAL OVERVIEW
ILNP takes a different approach to naming of communication
objects within the network stack. Two new data types are
introduced which subsume the role of the IP address at the
network and transport layers in the current IP architecture.
2.1 Identifiers and Locators
ILNP explicitly replaces the use of IP addresses with two
distinct name spaces, each having distinct and different
semantics:
a) Identifier: a non-topological name for uniquely identifying
a node.
b) Locator: a topologically-bound name for an IP subnetwork.
The use of these two new namespaces in comparison to IP is given
in Table 1. The table shows where existing names are used for
state information in end-systems or protocols.
Layer | IP | ILNP
---------------+----------------------+---------------
Application | FQDN or IP address | FQDN
Transport | IP address | Identifier
Network | IP address | Locator
Physical i/f | IP address | MAC address
---------------+----------------------+---------------
FQDN = Fully Qualified Domain Name
i/f = interface
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Table 1: Use of names for state information in various
communication layers for IP and ILNP.
As shown in Table 1, if an application uses a Fully-Qualified
Domain Name at the application-layer, there is, effectively, no
architectural difference to any naming used from the point of
view of the state information for an application-layer
session. We call such applications "well-behaved" with respect to
naming as use of the FQDN at the application-layer is recommended
in RFC1958 [RFC1958]. Some other applications also avoid use of
IP address information within the application-layer protocol; we
also consider these applications to be "well-behaved". Any
well-behaved application should be able to operate on ILNP
without any changes. Note that application level use of IP
addresses includes application-level configuration information,
e.g. Apache Web Server (httpd) configuration files make extensive
use of IP addresses as a form of identity.
ILNP does not require applications to be rewritten to use a new
Networking Application Programming Interface (API). So existing
well-behaved IP-based applications should be able to work over
ILNP as-is.
In ILNP, transport-layer protocols use only an end-to-end,
non-topological node Identifier. It is important to note that the
node Identifier names the node, not a specific interface of the
node. In this way, it has different semantics and properties than
either the IPv4 Address, the IPv6 Address, or the IPv6 Interface
Identifier.
The use of the ILNP Identifier value within application-layer
protocols is not recommended. Instead, the use of either a Fully
Qualified Domain Name (FQDN) or some different
topology-independent namespace is recommended.
At the network-layer, Locator values, which have topological
significance, are used for routing and forwarding of ILNP
packets, but Locators are not used in upper-layer protocols.
As well as the new namespaces, another significant difference in
ILNP, as shown in Table 1, is that there is no binding of a
routable name to an interface, or Sub-Network Point of Attachment
(SNPA), as there is in IP. The existence of such a binding in IP
effectively binds transport protocol flows to a specific, single
interface on a node. Also, application sessions that use IP
addresses effectively bind to a specific, single interface on a
node in their application-layer state. In ILNP, dynamic bindings
exist between Identifier values and associated Locator values, as
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well as between <Identifier, Locator> pairs and (physical or
logical) interfaces on the node.
This change enhances the Internet architecture by adding crisp
and clear semantics for the Identifier and for the Locator,
removing the overloaded semantics of the IP address [RFC1992]
[RFC4984], by updating end system protocols, but without
requiring any router or backbone changes. In ILNP, the closest
approximation to an IP address is an IL Vector (IL-V), which is a
given binding between an Identifier and Locator pair, written as
<I, L>. IL-Vs are discussed in more detail below.
Where, today, IP packets have:
- source IP address, destination IP address
instead ILNP packets have:
- source IL-V, destination IL-V
However, it must be emphasised that the IL-V and the IP address
are *not* equivalent.
With these naming enhancements, we will improve the Internet
architecture by adding explicit harmonised support for many
functions, such as multi-homing, mobility and IP Security.
2.2 Deprecating IP Addresses
ILNP places an explicit Locator and Identifier in the IP packet
header, replacing the usual IP address. Locators are tied to the
topology of the network. They may change frequently, as the node
or site changes its network connectivity. The node Identifier is
normally much more static, and remains constant throughout the
life of a given transport-layer session, and frequently much
longer. However, there are various options for Identifier values,
as will be discussed later.
Identifiers and Locators for hosts are advertised explicitly in
DNS, through the use of new Resource Records (RRs). This is a
logical and reasonable use of DNS, completely analogous to the
capability that DNS provides today. At present, among other
current uses, the DNS is used to map from an FQDN to a set of
addresses. As ILNP replaces addresses with Identifiers and
Locators, it is then clearly rational to use the DNS to map an
FQDN to a set of Identifiers and a set of Locators for a node.
The presence of ILNP Locators and Identifiers in the DNS for a
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DNS owner name is an indicator to correspondents that the
correspondents can try to establish an ILNP enhanced transport
session with that DNS owner name.
Specifically in response to [RFC4984], ILNP improves routing
scalability by helping multi-homed sites operate effectively with
provider-aggregatable (PA) address prefixes. Many multi-homed
sites today request provider-independent (PI) address prefixes so
they can provide session survivability despite the failure of one
or more access links or Internet Service Providers (ISPs). ILNP
provides this session survivability by having a
provider-independent node Identifier value that is free of any
topological semantics. This I value can be bound dynamically to a
provider-aggregatable L value, the latter being a topological
name i.e. a PA network prefix. By allowing correspondents to
change arbitrarily among multiple PA Locator values,
survivability is enabled as changes to the L values need not
disrupt transport-layer sessions. In turn, this allows an ILNP
multi-homed site to have the full session resilience that is
today offered by PI addressing while using the equivalent of PA
addressing, and so eliminates the current need to use globally
visible PI routing prefixes for each multi-homed site.
2.3 Other Goals
While we seek to make significant enhancements to the current
Internet Architecture, we also wish to ensure that instantiations
of ILNP are:
a) Backwards compatible: implementations of ILNP should be able
to work with existing IPv6 or IPv4 deployments, without
requiring application changes.
b) Incrementally deployable: to deploy an implementation of
ILNP, changes to the network nodes should only be for those
nodes that choose to use ILNP. The use of ILNP by some nodes
does not require other nodes (that do not use ILNP) to be
upgraded.
3. ARCHITECTURAL CHANGES INTRODUCED BY ILNP
In this section, we describe the key changes that are made to the
current Internet architecture. These key changes impact end
systems, rather than routers.
3.1 Identifiers
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Identifiers are non-topological values that identify an ILNP
node. A node might be a physical node or a virtual node. For
example, a single physical device might contain multiple
independent virtual nodes. Alternately, a single virtual device
might be composed from multiple physical devices. In the case of
a Multi-Level Secure (MLS) system, each valid sensitivity label
of that system might be a separate virtual node.
A node MAY have multiple Identifier values associated with it,
which MAY be used concurrently.
In normal operation when a node is responding to a received ILNP
packet that creates a new session, the correct I value to use for
that session with that correspondent node will be learned from
the received ILNP packet.
In normal operation when a node is initiating communication with
a correspondent node, the correct I value to use for that session
with that correspondent node will be learned either through the
application-layer naming, through DNS name resolution, through
some alternative name resolution system, or an application may be
able to select different I values directly as Identifiers are
visible above the network-layer via the transport protocol.
3.1.1 Identifiers are immutable during a session
Once an Identifier value has been used to establish a session it
forms part of the end-to-end (invariant) session state and so
must remain fixed for the duration of that session. This means,
for example, that throughout the duration of a given TCP session,
the source Identifier and destination Identifier values will not
change.
In normal operation, a node will not change its set of valid
Identifier values frequently. However, a node MAY change its set
of valid Identifier values over time, for example in an effort to
provide identity obfuscation, while remaining subject to the
architectural rule of the preceding paragraph.
3.1.2 Syntax
ILNP Identifiers have the same syntax as IPv6 Interface
Identifiers, based on the EUI-64 format, which helps with
backwards compatibility. There is no semantic equivalent
to an ILNP Identifier in IPv4 or IPv6 today.
The Modified EUI-64 syntax used by both ILNP Identifiers and IPv6
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Interface Identifiers contains a bit indicating whether the value
has global-scope or local-scope. ILNP Identifiers have either
global-scope or local-scope. If they have global scope, they
SHOULD be globally unique.
Regardless of whether an Identifier is global-scope or
local-scope, an Identifier MUST be unique within the scope of a
given Locator value to which it is bound for a given session or
packet flow. As an example, with ILNPv6, the ordinary IPv6
Neighbour Discovery (ND) processes ensure that this is true, just
as ND ensures that no two IPv6 nodes on the same IPv6 subnetwork
have the same IPv6 address at the same time.
The Modified EUI-64 syntax used by both ILNP Identifiers and IPv6
Interface Identifiers contains a bit indicating whether the value
is unicast or multicast. ILNP Identifiers can be either unicast,
in which case they identify a node, or multicast, in which case
they identify a multicast group. At the current time, the use of
an identifier with the multicast bit set is currently left for
further study.
3.1.3 Semantics
Unicast Identifier values name the node, rather than naming a
specific interface on that node. So ILNP Identifiers have
different semantics than IPv6 Interface Identifiers.
For naming multicast destinations, ILNP currently uses the same
architecture as for IP.
3.2 Locators
Locators are topologically-significant names, analogous to
(sub)network routing prefixes. The Locator names the IP
subnetwork that a node is connected to. ILNP neither prohibits
nor mandates in-transit modification of Locator values.
A host MAY have several Locators at the same time, for example
if it has a single network interface connected to multiple
subnetworks (e.g. VLAN deployments on wired Ethernet), or has
multiple interfaces each on a different subnetwork. Locator
values normally have Locator Precedence Indicator (LPI) values
associated with them. These LPIs indicate that a specific Locator
value has higher or lower precedence for use at a given
time. Local LPI values may be changed through local policy or via
management interfaces. Remote LPI values are normally learned
from the DNS, but the local copy of a remote LPI value might be
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modified by local policy relating to preferred paths or prefixes.
Locator values are used only at the network-layer. Locators are
not used in end-to-end transport state. For example, Locators are
not used in transport-layer protocol state or application session
state. However, this does not preclude an end-system setting up
local dynamic bindings for a single transport flow to multiple
Locator values concurrently.
The routing system only uses Locators, not Identifiers. For
unicast traffic, ILNP uses longest-prefix match routing, just as
the IP Internet does. With ILNP multicasting, the Destination
Locator names a subnetwork that has a multicast routing
Rendezvous Point (RP) for the multicast group named by the
Destination Identifier. Section X.Y below describes in more
detail how Locators are used by the routing system to forward
packets from a sending node on an origin subnetwork to one or
more receiving nodes on one or more destination subnetworks.
In normal operation, the originating host supplies both Source
Locator and Destination Locator values in the packets it sends
out.
Section 4.2 describes packet forwarding in more detail, while
Section 4.3 describes packet routing in more detail.
3.2.1 Locator Values are Dynamic
The ILNP architecture recognises that Locator values are
topologically significant, so the set of Locator values
associated with a node normally will need to change when the
node's connectivity to the Internet topology changes. For
example, a mobile or multi-homed node is likely to have
connectivity changes from time to time, along with the
corresponding changes to the set of Locator values.
When a node using a specific set of Locator values changes one
or more of those Locator values, then the node (1) needs to
update its local knowledge of its own Locator values, (2) needs
to inform all active Correspondent Nodes (CNs) of those changes
to its set of Locator values so that ILNP session continuity is
maintained, and (3) if it expects incoming connections the node
also needs to update its Locator related entries in the Domain
Name System. [ILNP-ENG] describes the engineering and
implementation details of this process.
3.2.2 Syntax
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ILNP Locators have the same syntax as an IP unicast routing prefix.
3.2.3 Semantics
ILNP unicast Locators have the same semantics as an IP unicast
routing prefix, since they name a specific subnetwork. IP
multicast Locators name a Rendezvous Point (RP), which is a
subnetwork where at least one router is able to forward packets
for the ILNP Multicast group named by the Destination
Identifier. ILNP neither prohibits nor requires in-transit
modification of Locator values.
3.3 IP Address and Identifier-Locator Vector (IL-V)
* Authors' note to reviewers: We value reviewers comments on this
terminology. Other terminology might be "IL coordinate" or "IL
combination".
Historically, an IP Address has been considered to be an atomic
datum, even though it is recognised that an IP address has an
internal structure: the network prefix plus either the host ID
(IPv4) or the interface identifier (IPv6). However, this internal
structure has not been used in end-system protocols: instead all
the bits of the IP address are used. (Additionally, in IPv4 the
IPv4 sub-net mask uses bits from the host ID, a further confusion
of the structure, even thought it is an extremely useful
engineering mechanism.)
In ILNP, the IP address is replaced by an "Identifier-Locator
Vector" (IL-V). This consists of a pairing of an Identifier value
and a Locator value for that packet, written as <I,L>. All ILNP
packets have Source Identifier, Source Locator, Destination
Identifier, and Destination Locator values. The I value of the
IL-V is used by upper-layer protocols (e.g. TCP, UDP, SCTP), so
needs to be immutable. Locators are not used by upper-layer
protocols (e.g. TCP, UDP, SCTP). Instead, Locators are similar to
IP routing prefixes, and are only used to name a specific
subnetwork.
While it is possible to say that an IL-V is an approximation
to an IP address of today, it should be understood that
an IL-V:
a) is not an atomic datum, being a pairing of two data types,
an Identifier and a Locator.
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b) has different semantics and properties to an IP address,
as is described in this document.
In our discussion, it will be convenient sometimes to refer to an
IL-V, but sometimes to refer only to an Identifier value, or only
to a Locator value.
ILNP packets always contain a source IL-V and a destination IL-V.
3.4 Notation
In describing how capabilities are implemented in ILNP, we will
consider the differences in end-systems state between IP and ILNP
in order to highlight the architectural changes.
We define a formal notation to represent the data contained in
the communications session state. We define:
A = IP address
I = Identifier
L = Locator
P = Transport-layer port number
To differentiate the local and remote values for the above items,
we also use suffixes, for example:
_L = local
_R = remote
With IPv4 and IPv6 today, the invariant state at the
transport-layer for TCP can be represented by the tagged tuple:
<TCP: A_L, A_R, P_L, P_R> --- (1)
Tag values that will be used are:
IP Internet Protocol
ILNP Identifier Locator Network Protocol
TCP Transmission Control Protocol
UDP User Datagram Protocol
So, for example, with IP, a UDP packet would have the
tagged tuple:
<UDP: A_L, A_R, P_L, P_R> --- (2)
A TCP segment carried in an IP packet may be represented by the
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tagged tuple binding:
<TCP: A_L, A_R, P_L, P_R><IP: A_L, A_R> --- (3)
and a UDP packet would have the tagged tuple binding:
<UDP: A_L, A_R, P_L, P_R><IP: A_L, A_R> --- (4)
In ILNP, the transport-layer state for TCP is:
<TCP: I_L, I_R, P_L, P_R> --- (5)
The binding for a TCP segment within an ILNP packet:
<TCP: I_L, I_R, P_L, P_R><ILNP: L_L, L_R> --- (6)
When comparing tuple expressions (3) and (6), we see that for IP,
any change to network addresses impacts the end-to-end state, but
for ILNP, changes to Locator values do not impact end-to-end
state, providing end-system session state invariance, a key
feature of ILNP compared to IP as it is used in some situations
today. ILNP adopts the end-to-end approach for its architecture
[SRC84]. As noted previously, nodes MAY have more than one
Locator concurrently and nodes MAY change their set of active
Locator values as required.
3.5 Transport-layer state and transport pseudo-headers
In ILNP, protocols above the network-layer do not use the Locator
values. Thus, the transport-layer uses only the I values for the
transport-layer state (e.g. TCP checksum, UDP checksum), as is
shown, for example, in expression (6) above.
Additionally, again from a practical perspective, while the I
values are only used in protocols above the network-layer, it is
convenient for them to be carried in network packets, so that the
namespace for the I values can be used by any transport-layer
protocols operating above the common network-layer.
3.6 Rationale for this document
This document provides an architectural description of the core
ILNP capabilities and functions. It is based around the use of
example scenarios so that practical issues can be highlighted.
In some cases, illustrative suggestions and light
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discussion are presented with respect to engineering issues,
but detailed discussion of engineering issues are deferred
to other ILNP documents.
The order of the examples presented below are intended
to allow an incremental technical understanding of ILNP
to be developed. There is no other reason for the ordering
of the examples listed below.
Many of the descriptions are based on the use of an example
site network as shown in Figure 2.1.
site . . . . +----+
network . .-----+ CN |
. . . . +------+ . . +----+
. . | +------. .
. D . | | . .
. .----+ SBR | . Internet .
. H . | | . .
. . | +------. .
. . . . +------+ . .
. .
. . . .
CN = Correspondent Node
D = Device
H = Host
SBR = Site Border Router
Figure 2.1: A simple site network for ILNP examples.
In some cases, hosts (H) or devices (D) act as end-systems
within the site network, and communicate with (one or more)
Correspondent Node (CN) instances that are beyond the site.
Note that the Figure is illustrative and presents a logical
view. For example, the CN may itself be on a site network,
just like H or D.
Also, for formulating examples, we assume ILNPv6 is in use,
which has the same packet header format (as viewed by
routers) as IPv6, and can be seen as a superset of IPv6
capabilities.
For simplicity, we assume that name resolution is via the
deployed DNS which has been updated to store DNS records
for ILNP [ILNP-DNS].
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Note that, from an engineering viewpoint, this does NOT mean
that the DNS also has to be ILNP capable: existing IPv4 or
IPv6 infrastructure can be used for DNS transport.
4. ILNP BASIC CONNECTIVITY
In this section, we describe the operation of basic functionality
of packet forwarding and routing in ILNP. We highlight areas
where it is similar to current IP and where it is different from
current IP. We also use examples in order to illustrate the
intent and show the feasibility of the approach.
For this section, in Figure 4.1, H is a fixed host in a simple
site network, CN is a remote Correspondent Node outside the site,
H and CN are ILNP-capable, while the Site Border Router (SBR)
does not need to be ILNP-capable.
site . . . . +----+
network . .-----+ CN |
. . . . +------+ . . +----+
. . | +------. .
. . | | . .
. .----+ SBR | . Internet .
. H . | | . .
. . | | . .
. . . . +------+ . .
. .
. . . .
CN = Correspondent Node
H = Host
SBR = Site Border Router
Figure 4.1: A simple site network for ILNP examples.
4.1 Basic Local Configuration
This section uses the term "Address management", in recognition
of the analogy with capabilities present in IP today. In this
document, address management is about enabling hosts to attach to
a subnetwork and enabling network-layer communication between and
among hosts, also including:
a) enabling identification of a node within a site.
b) allowing basic routing/forwarding from a node acting as
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an end-system.
If we consider Figure 4.1, imagine that host H has been connected
to the site network. Administratively, it needs at least one I
value and one L value in order to be able to communicate.
Today, local administrative procedures allocate IP addresses,
often using various protocol mechanisms (e.g. NetConf-based
router configuration, DHCP for IPv4, DHCP for IPv6, IPv6 Router
Advertisements). Similarly, local administrative procedures can
allocate I and L values as required, e.g. I_H and L_H. This may
be through manual configuration.
Additionally, if it is expected or desired that H might have
incoming communication requests, e.g. it is a server, then the
values I_H and L_H can be added to the relevant name services
(e.g. DNS, NIS/YP), so that FQDN lookups for H resolve to the
appropriate DNS resource records (e.g. ID, L32, L64, and LP
[ILNP-DNS]) for node H.
From a network operations perspective, this whole process also
can be automated. As an example, consider that in Figure 3.1 the
Site Border Router (SBR) is an IPv6 capable router and is
connected via link1 to an ISP that supports IPv6. SBR will have
been allocated one (or more) IPv6 prefixes that it will multicast
using IPv6 Routing Advertisements (RAs) into the site network,
e.g. say prefix L_1. L_1 is actually a local IPv6 prefix (/64),
which is formed from an address assignment by the upstream ISP,
according to [RFC3177] (/48) or [RFC6177] (/56). Host H will see
these RAs, for example, on its local interface with name eth0,
will be able to use that prefix as a Locator value, and will
cache that Locator value locally.
Also, node H can use the mechanism documented in either Section
2.5.1 of [RFC4291], in [RFC3972] [RFC4581] [RFC4982], or in
[RFC4941] in order to create a default I value, say I_H, just as
an IPv6 host can. For DNS, the I_H and L_1 values may be
pre-configured in DNS by an administrator who already has
knowledge of these, or added to DNS by H using Secure DNS Dynamic
Update [RFC3007] to add or update the correct ID and L64 records
to DNS for the FQDN for H.
For the purposes of explaining the concept of operations, we talk
of a local I-L Correspondent Cache (ILCC). This is an engineering
convenience and does not form part of the ILNP architecture,
but is used in our examples. More details on the ILCC can be
found in [ILNP-ENG].
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4.2 Packet Forwarding
When the SBR needs to send a packet to H, it uses local address
resolution mechanisms to discover the bindings between interface
addresses and currently active IL-Vs for H. For our example of
Figure 3.1, IPv6 Neighbour Discovery (ND) can be used without
modification, as the IL-V for ILNPv6 occupies the same bits as
the IPv6 address in the IPv6 header. For packets from H to SBR,
the same basic mechanism applies, as long as SBR supports IPv6
and even if it is not ILNPv6-capable, as IPv6 ND is used
unmodified for ILNPv6.
For Figure 3.1, assuming:
- SBR advertises prefix L_1 locally, uses I value I_S, and has
an Ethernet MAC address M_S on interface with local name sbr0
- H uses I value I_H, and has an ethernet MAC address of M_H on
the interface with local name eth0
then H will have in its ILCC:
<I_H, L_1> --- (7a)
L_1, eth0 --- (7b)
After the IPv6 RA and ND mechanism has executed, the ILCC at H
would contain, as well as (7a) and (7b), the following entry for
SBR:
<I_S ,L_1>, M_S --- (8)
For ILNPv6, it does not matter that the SBR is not ILNPv6
capable, as the IL-V <I_S,L_1> is physically equivalent to the
IPv6 address for the internal interface sbr0.
At SBR, which is not ILNP-capable, there would be the following
entries in its local cache and configuration:
L_1:I_S --- (9a)
L_1, sbr0 --- (9b)
Expression (9a) represents a valid IPv6 ND entry: in this case,
the I_S value (which is 64 bits in ILNPv6) and the L_1 values
are, effectively, concatenated and treated as if they were a
single IPv6 address. Expression (9b) binds transmissions for L_1
to interface sbr0 (again, sbr0 is a local, implementation-
specific name, and such a binding is possible with standard tools
today, for example ifconfig(8)).
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4.3 Packet Routing
If we assume that host H is configured as in the previous
section, it is now ready to send and receive ILNP packets.
Let us assume that, for Figure 3.1, it wishes to contact the
node CN, which has FQDN cn.example.com and is ILNP-capable.
A DNS query by H for cn.example.com will result in ID and L64
records for CN, with values I_CN and L_CN, respectively,
being returned to H, and stored in its ILCC:
<I_CN, L_CN> --- (10)
This will be considered active, as long as the TTL values for the
DNS records are valid. If the TTL for an I or L value is zero,
then the value is still useable but becomes stale as soon as it
has been used once. However, it is more likely that the TTL value
will be greater than zero [BA2011].
Once the CN's I value is known, the upper layer protocol,
e.g. the transport protocol, can set up suitable session
state:
<UDP: I_H, I_CN, P_H, P_CN> --- (11)
For routing of ILNP packets, the destination L value in an ILNPv6
packet header is semantically equivalent to a routing prefix.
So, once a packet has been forwarded from a host to its first-hop
router, only the destination L value needs to be used for getting
the packet to the destination network. Once the packet has
arrived at the router for the site network, local mechanisms and
packet forwarding mechanism, as described in Sec 4.2, allow the
packet to be delivered to the host.
For our example of Figure 4.1, H will send a UDP packet
over ILNP as:
<UDP: I_H, I_CN, P_H, P_CN><ILNP: L_1, L_CN> --- (12a)
and CN will send UDP packets to H as:
<UDP: I_CN, I_H, P_CN, P_H><ILNP: L_CN, L_1> --- (12b)
The I value for H used in the transport-layer state (I_H in
expression (12a)) selects the correct L value (L_1 in this case)
from the bindings in the ILCC (expression (7a)), and that, in
turn, selects the correct interface from the ILCC (expression
(7b)), as described in Sec 4.2. This gets the packet to the first
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hop router, and beyond that, the ILNPv6 packet is treated as if
it were an IPv6 packet.
5.0 MULTI-HOMING AND MULTI-PATH TRANSPORT
For multi-homing, there are three cases to consider:
a) Host Multi-Homing (H-MH): a single host is, individually,
connected to multiple upstream links, via separate routing
paths, and those multiple paths are used by that host as it
wishes. That is, use of multiple upstream links is managed
by the single host itself. For example, the host might have
multiple valid Locator values on a single interface, with
each Locator value being associated with a different
upstream link (provider).
b) Multi-Path Transport (MTP): This is, in the case of ILNP,
functionally similar to enabling an ILNP-capable host to have
multi-homing capability (i.e. H-MH), so we describe this
functionality here also. (Indeed, for ILNP, this can be
considered a special case of H-MH.)
c) Site Multi-Homing (S-MH): a site network is connected to
multiple upstream links via separate routing paths, and hosts
on the site are not necessarily aware of the multiple
upstream paths. That is, the multiple upstream paths are
managed, typically, through a site-border router, or via the
providers.
Essentially, for ILNP, multi-homing is implemented by enabling:
a) multiple Locator values to be used simultaneously by a node
b) dynamic, simultaneous binding between one (or more)
Identifier value(s) and multiple Locator values
5.1 Host Multi-Homing (H-MH)
At present, host multi-homing is not common in the deployed
Internet. When TCP or UDP are in use for an IP session, host
multi-homing cannot provide session resilience, because the
transport pseudo-header checksum binds the session to a single
address of the multi-homed node, and hence to a single
interface. SCTP has a protocol-specific mechanism to support node
multi-homing; SCTP can support session resilience both at present
and also without change in the proposed approach [RFC5061].
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Host multi-homing in ILNP is supported directly in each host by
ILNP. The simplest explanation of H-MH for ILNP is that an
ILNP-capable host can simultaneously use multiple Locator values,
for example by having a binding between an I value and two
different L values, e.g. the ILCC may contain the IL-Vs:
<I_1, L_1> --- (14a)
<I_1, L_2> --- (14b)
Additionally, a host may use several I values concurrently,
e.g. the ILCC may contain the IL-Vs:
<I_1, L_1> --- (15a)
<I_1, L_2> --- (15b)
<I_2, L_2> --- (15c)
<I_3, L_1> --- (15d)
Architecturally, ILNP considers these all to be cases of
multi-homing: the host is connected to more than one
subnetwork, each subnetwork being named by a different
Locator value.
In the cases above, the selection of which IL-V to use
would be through local policy or through management
mechanisms. Additionally, suitably modified transport-layer
protocols, such as multi-path transport-layer protocol
implementations, may make use of multiple IL-Vs. Note that
in such a case, the way in which multiple IL-Vs are used
would be under the control of the higher-layer protocol.
Recall, however, that L values also have precedence - LPI
values - and these LPI values can be used at the network-layer,
or by a transport-layer protocol implementation, in order
make use of L values in a specific manner.
Note that, from a practical perspective, ILNP dynamically binds
L values to interfaces on a node to indicate the SNPA for that
L value, so the multi-homing is very flexible: a node could have
a single interface and have multiple L values bound to that
interface. For example, for expressions (14a) and (14b) if the
end-system has a single interface with local name eth0, then the
entries in the ILCC will be:
L_1, eth0 --- (16a)
L_2, eth0 --- (16b)
and if we assume that for expressions (15a-c), the end-system
has two interfaces, eth0 and eth1, then these ILCC entries
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are possible:
L_1, eth0 --- (17a)
L_2, eth1 --- (17b)
Let us consider the network in Figure 5.1.
site . . . .
network . .
. . . . +------+ L_1 . .
. . | +------. .
. . | | . .
. .----+ SBR | . Internet .
. . | | . .
. H . | +------. .
. . . . +------+ L_2 . .
. .
. . . .
L_1 = global Locator value 1
L_2 = global Locator value 2
SBR = Site Border Router
Figure 5.1: A simple multi-homing scenario for ILNP.
We assume that H has a single interface, eth0. SBR will advertise
L_1 and L_2 internally to the site. Host H will configure these
as both reachable via its single interface, eth0, by using ILCC
entries as in expressions (16a) and (16b). When packets from H
that are to egress the site network reach SBR, it can make
appropriate decisions on which link to use based on the source
Locator value (which has been inserted by H), or based on other
local policy.
If, however, H has two interfaces, eth0 and eth1, then it can use
ILCC entries as in expressions (17a) and (17b).
Note that the values L_1 and L_2 do not need to be PI based
Locator values, and can be taken from ISP-specific PA routing
prefix allocations from the upstream ISPs providing the two
links.
Of course, this example is illustrative: many other
configurations are also possible, but the fundamental mechanism
remains the same, as described above.
If any Locator values change then H will discover this when it
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sees new Locator values in RAs from SBR, and sees that L values
that were previously used are no longer advertised. When this
happens, H will:
a) maintain existing active upper layer sessions: based on its
current ILCC entries and active sessions, send Locator
Update (LU) messages to CNs to notify them of the change of
L values. (LU messages are synonymous to IPv6 Binding
Updates.)
b) if required, update its relevant DNS entries with the new L
value in the appropriate DNS records, to enable correct
resolution for new incoming session requests.
From an engineering view point, H also updates its ILCC data,
removing the old L value(s) and replacing with new L value(s) as
required.
Depending on the nature of the physical change in connectivity
that the L value change represents, this may disrupt upper-level
protocols, e.g. a fibre cut. Dealing with such physical-level
disruption is beyond the scope of ILNP. However, ILNP supports
graceful changes in L values, and this is explained below in Sec
XXXX in the discussion on mobility support.
5.2 Support for Multi-Path Transport Protocols (MTPs)
ILNP will support multi-path transport protocols, such as those
defined by the IETF TCPM Working Group. Specifically, ILNP will
support the use of multiple paths as it allows a single I value
to be bound to multiple L values - see Sec 5.1 and specifically
expressions (15a) and (15b). Of course, there will be specific
mechanisms for:
- congestion control
- signalling for connection/session management
- path discovery and path management
- engineering and implementation issues
which fall outside the scope of ILNP and would be defined by the
higher-level protocol definition for the multi-path transport
protocol. As far as the ILNP architecture is concerned, the
transport protocol connection is simply using multiple IL-Vs,
but with the same I value in each, and different L values,
i.e. a multi-homed host.
5.3 Site multi-homing (S-MH)
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At present, site multi-homing is common in the deployed
Internet. This is primarily achieved by advertising the site's
routing prefix(es) to more than one upstream Internet service
provider at a given time. In turn, this requires de-aggregation
of routing prefixes within the inter-domain routing system. This
increases the entropy of the inter-domain routing system
(e.g. RIB/FIB size increases beyond the minimal RIB/FIB size that
would be required to reach all sites).
Site multi-homing, in its simplest form in ILNP, is an extension
of the H-MH scenario described in Sec 5.1. If we consider Figure
5.1 and assume that there are many hosts in the site network,
each can choose to manage its own ILNP connectivity and whether
or not multiple Locator values are used. This allows maximal
control of connectivity for each host.
Of course, with ILNPv6, just as any IPv6 router is required to
generate IPv6 Router Advertisement messages with the correct
routing prefix information for the link the RA is advertised
upon, thus also the SBR is required to generate RAs containing
the correct Locator value(s) for the link that the RA is
advertised upon. The correct values for these RA messages are
typically configured by system administration, or might be passed
down from the upstream provider.
To avoid a DNS Update burst when a site or (sub)network changes
location, a DNS record optimisation is possible by using the new
LP record for ILNP. This would change the number of DNS Updates
required from O(Number of nodes at the site/subnetwork that
moved) to O(1) [ILNP-DNS].
5.4 Multi-Homing Requirements for Site Border Routers
For multi-homing, the SBR does NOT need to be ILNP-capable for
Host Multi-Homing or Site Multi-Homing. This is true provided the
multi-homing is left to individual hosts as described above. In
this deployment approach, the SBR need only issue Routing
Advertisements (RAs) that are correct with respect to its
upstream connectivity; that is, the SBR properly advertises
routing prefixes (Locator values) to the ILNP hosts.
In such a scenario, when hosts in the site network see new
Locator values, and see that a previous Locator value is no
longer being advertised, those hosts can update their ILCCs,
send Locator Updates to CNs, and change connectivity
as required.
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6. MOBILITY
ILNP supports mobility directly. There are two different
mobility cases to consider:
a) Host Mobility: individual hosts may be mobile, moving across
administrative boundaries or topological boundaries within
an IP-based network, or across the Internet. Such hosts
would need to independently manage their own mobility.
b) Network (Site) Mobility: a whole site, i.e. one (or more) IP
subnetwork(s) may be mobile, moving across administrative
boundaries or topological boundaries within an IP-based
network, or across the Internet. The site as a whole needs
to maintain consistency in connectivity.
Essentially, for ILNP, mobility is implemented by enabling:
a) Locator values to be changed dynamically by a node,
including for active sessions.
b) use of Locator Updates to allow active sessions to be
maintained.
c) for those hosts that expect incoming session requests
(such as servers), updates to the relevant DNS entries
for those hosts.
For mobility, there are two general features that must be
supported:
a) Handover (or Hand-off): when a host changes its connectivity
(e.g. it has a new SNPA as it moves to a new ILNP
subnetwork), any active sessions for that host must be
maintained with minimal disruption (i.e. transparently) to
the upper layer protocols.
b) Rendezvous: when a host that expects incoming session
requests has new connectivity (e.g. it has a new SNPA as it
moves to a new ILNP subnetwork), it must update its relevant
DNS entries so that name resolution will provide the correct
I and L values to remote nodes.
6.1 Mobility/multi-homing duality in ILNP
Mobility and multi-homing present the same set of issues for
ILNP. Indeed, mobility and multi-homing form a duality:
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the set of Locators associated with a node or site changes. The
reason for the change might be different for the case of mobility
and multi-homing, but the effects on the network session state
and on correspondents is identical.
With ILNP, mobility and multi-homing are supported using a common
set of mechanisms. In both cases, different Locator values are
used to identify different IP subnetworks. Also, ILNP nodes that
expect incoming session requests are assumed to have a Fully
Qualified Domain Name (FQDN) stored in the Domain Name System
(DNS), as is already done within the deployed Internet.
Host Mobility considers individual hosts that are individually
mobile, for example a mobile telephone carried by a person
walking in a city. Network (Site) Mobility considers a group of
hosts within a local topology that move jointly and periodically
change their uplinks to the rest of the Internet, for example a
ship that has wired connections internally but one or more
wireless uplinks to the rest of the Internet.
For ILNP, Host Mobility is analogous to Host Multi-homing (H-MH)
and Network Mobility is analogous to Site Multi-homing
(S-MH). So, mobility and multi-homing functionality can be used
together, without conflict.
6.1 Host Mobility
With host mobility, each individual end-system manages its own
connectivity through the use of Locator values. (This is very
similar to the situation described for H-MH in Sec 5.1.)
Let us consider the network in Figure 6.1.
site . . . .
network A . .
. . . . +-------+ L_A . .
. . | +------. .
. . | | . .
. .---+ SBR_A | . .
. . | | . .
. H(1) . | | . .
. . +-------+ . .
. . . . . . . .
. H(2) . . Internet .
. . . . . . . .
. . +-------+ L_B . .
. H(3) . | +------. .
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. . | | . .
. .---+ SBR_B | . .
. . | | . .
. . | | . .
. . . . +-------+ . .
site . .
network B . . . .
H(X) = host H at position X
L_A = global Locator value A
L_B = global Locator value B
SBR = Site Border Router
Figure 6.1: A simple mobile host scenario for ILNP.
A host, H is at position (1), hence H(1), in a site network
A. This site network might be, for example, a single radio-cell
under administrative domain A. We assume that the host will move
into site network B, which might be a single radio-cell under
administrative domain B. We also assume that the site networks
have a region of overlap so that connectivity can be maintained,
else, of course, the host will loose connectivity. Also, let us
assume that the host already has ILNP connectivity in site
network A.
If site network A has connectivity via Locator value L_A, and H
uses Identifier value I_H with a single interface ra0, then the
host's ILCC will contain:
<I_H, L_A> --- (18a)
L_A, ra0 --- (18b)
Note the equivalence of expressions (18a) and (18b),
respectively, with the expressions (15a) and (16a)
for host multi-homing.
The host now moves into the overlap region of site networks A and
B, and has position (2), H(2) as indicated in Fig 6.1. As this
region is now in site network B, as well as site network A, H
should see RAs from SBR_B for L_B, as well as the RAs for L_A
from SBR_A. The host can now start to use L_B for its
connectivity. The host H must now:
a) maintain existing active upper layer sessions: based on its
current ILCC entries and active sessions, send Locator
Update (LU) messages to CNs to notify them of the change of
L values. (LU messages are synonymous to IPv6 Binding
Updates.)
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b) if required, update its relevant DNS entries with the new L
value in the appropriate DNS records, to enable correct
resolution for new incoming session requests.
However, it can opt to do this one of two ways:
1) immediate handover: the host sends Locator Update (LU)
messages to CNs, immediately stops using L_A and switches
to using L_B only. In this case, its ILCC entries
change to:
<I_H, L_B> --- (19a)
L_B, ra0 --- (19b)
There might be packets in flight to H which use L_A and H
MAY choose to ignore these on reception.
2) soft handover: the host sends Locator Update (LU) messages
to CNS, but it uses both L_A and L_B until (i) it longer
receives incoming packets with destination Locator values
set to L_A within a given time period (ii) it no longer sees
RAs for L_A (i.e. it has left the overlap region and so has
left site network A). In this case, its ILCC entries change
to:
<I_H, L_A> --- (20a)
L_A, ra0 --- (20b)
<I_H, L_B> --- (20c)
L_B, ra0 --- (20d)
ILNP does not mandate the use of one handover option over
another. Indeed, a host may implement both and decide, through
local policy or other mechanisms (e.g. under the control of a
particular transport protocol implementation), to use one or
other for a specific session, as required.
Note that if using soft handover, when in the overlap region
the host is multi-homed. Also, soft handover is likely to
provide a less disruptive handover (e.g. lower packet loss)
compared to immediate handover, all other things being equal.
There is a case where both the host and its correspondent node
are mobile. In the unlikely event of simultaneous motion which
changes both nodes' Locators within a very small time period,
there is the possibility that communication may be lost. If the
communication between the nodes was direct (i.e. one node
initiated communication with another, through a DNS lookup)
a node can use the DNS to discover the new Locator value(s) for
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the other node. If the communication was through some sort of
middlebox providing a relay service, then communication is more
likely to disrupted only if the middlebox is also mobile.
It is also possible that high packet loss results in Locator
Updates being lost, which could disrupt handover. However, this
is an engineering issue and does not impact the basic concept of
operation: additional discussion on this issue is provided in
[ILNP-ENG].
Of course, for any handover, the new end-to-end path through
SBR_B might have very different end-to-end path characteristics
(e.g. different end-to-end delay, packet-loss,
throughput). Also, the physical connectivity on interface ra0
as well as through SBR_B's uplink may be different. Such impact
on end-to-end packet transfer are outside the scope of ILNP.
6.2 Network Mobility
For network mobility, a whole site may be mobile, e.g. the SBRs
of Figure 6.1 has a radio uplink on a moving vehicle. Within the
site, individual hosts may or may not be mobile.
In the simplest case, ILNP deals with mobile networks in the
same way as for site multi-homing: the management of mobility
is delegated to each host in the site, so it needs to be
ILNP-capable. Each host, effectively, behaves as if it was a
mobile host, even though it may not actually be mobile. Indeed,
in this way, the mechanism is very similar to that for site
multi-homing.
Let us consider the mobile network in Figure 6.2.
site ISP_1
network SBR . . .
. . . . +------+ L_1 . .
. . | ra1+------. .
. .----+ | . .
. H . | ra2+-- . .
. . . . +------+ . .
. . .
Figure 6.2a: ILNP mobile network before handover.
site ISP_1
network SBR . . .
. . . . +------+ L_1 . .
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. . | ra1+------. . . . .
. .----+ | . .
. H . | ra2+------. .
. . . . +------+ L_2 . . . . .
. .
. . .
ISP_2
Figure 6.2b: ILNP mobile network during handover.
site ISP_2
network SBR . . .
. . . . +------+ . .
. . | ra1+-- . .
. .----+ | . .
. H . | ra2+------. .
. . . . +------+ . .
. . .
Figure 6.2c: ILNP mobile network after handover.
H = host
L_1 = global Locator value 1
L_2 = global Locator value 2
SBR = Site Border Router
Figure 6.2: A simple mobile network scenario for ILNP.
In Figure 6.2, we assume that the site network is mobile,
and the SBR has two radio interfaces ra1 and ra2. However,
this particular figure is chosen for simplicity and clarity
for our scenario, and other configurations are possible,
e.g. a single radio interface which uses separate radio
channels (separate carriers, coding channels, etc.) In the
figure, ISP_1 and ISP_2 are separate, radio-based service
providers, accessible via ra1 and ra2.
In Fig 6.2a, the SBR has connectivity via ISP_1 using Locator
value L_1. The host H, with interface ra0 and Identifier I_H,
has an established connectivity via the SBR and so has ILCC
entries as shown in (21):
<I_H, L_1> --- (21a)
L_1, ra0 --- (21b)
Note the equivalence to expressions (18a) and (18b). As the whole
network moves, the SBR detects a new radio provider, ISP_2, and
connects to it using ra2, as shown in Figure 6.2b, with the
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service areas of ISP_1 and ISP_2 overlapping. ISP_2 provides
Locator L_2, which SBR advertises into the site network along
with L_1. As with the mobile host scenario above, individual
hosts may decide to perform immediate handover or soft
handover. So, the ILCC state for H will be as for expressions
(19a,b) and (20a,b,c,d), but with L_1 in place of L_A and L_2 in
place of L_B. Finally, as in Figure 6.2c, the site network moves
and is no longer served by ISP_1, and handover is complete. Note
that during the handover the site is multi-homed, as in Figure
6.2b.
6.3 Mobility Requirements for Site Border Routers
As for multi-homing, the SBR does NOT need to be ILNP-capable:
it simply needs to advertise the available routing prefixes
into the site network. The mobility functionality is handled
completely by the hosts.
7. IP SECURITY WITH ILNP
IP Security for ILNP [ILNP-ENG] becomes simpler, in principle,
than IP Security as it is today, based on the use of IP addresses
as Identifiers. An operational issue in the deployed IP Internet
is that the IP Security protocols, AH and ESP, have Security
Associations (SAs) that include the IP addresses of the secure
session endpoints. This was understood to be a problem when AH
and ESP were originally defined. However, the limited set of
namespaces in the Internet Architecture did not provide any
better choices at that time. ILNP provides more namespaces.
7.1 Adapting IP security for ILNP
In essence, ILNP provides a very simple architectural change to
IP security: in place of IP addresses as used today for SAs, ILNP
uses Identifier values instead for SAs. Recall that Identifier
values are immutable once in use, so they can be used to maintain
end-to-end state for any protocol that requires it. Note from the
discussion above that the Identifier values for a host remain
unchanged when multi-homing and mobility is in use, so IP
security using ILNP can work in harmony with multi-homing and
mobility [MILCOM08] [MILCOM09].
Similarly, key management protocols used with IPsec would be
enhanced to deprecate use of IP addresses as identifiers and to
substitute the use of the new Identifier values for that purpose.
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To resolve the issue of IPsec interoperability through a NAT
deployment, UDP encapsulation of IPsec is increasingly commonly
used today [RFC3948]. This ought not be needed with ILNP.
Further, it would obviate the need for specialised IPsec NAT
Traversal mechanisms, thus simplifying IPsec implementations
while enhancing deployability and interoperability [RFC3948].
This change does not reduce the security provided by the IP
Security protocols.
7.2 Operational use of IP security with ILNP
Operationally, this change in SA bindings to use Identifiers
rather than IP addresses causes problems for the use of the IPsec
protocols through IP Network Address Translation (NAT) devices,
with mobile nodes (because the mobile node's IP address changes
at each network-layer handoff), and with multi-homed nodes
(because the session is bound to a particular interface of the
multi-homed node, rather than being bound to the node itself)
[RFC3027] [RFC3715].
8. BACKWARDS COMPATIBILITY & INCREMENTAL DEPLOYMENT
ILNPv6 is fully backwards compatible with existing IPv6. No
router software or silicon changes are necessary to support the
proposed enhancements. An IPv6 router would be unaware whether
the packet being forwarded were classic IPv6 or the proposed
enhancement in ILNPv6. IPv6 Neighbour Discovery will work
unchanged for ILNPv6.
ILNPv4 is backwards compatible with existing IPv4. As the IPv4
address fields are used as 32-bit Locators, using only the
address prefix bits of the the 32-bit space, IPv4 routers also
would not require changes. An IPv4 router would be unaware
whether the packet being forwarded were classic IPv4 or the
proposed enhancement in ILNPv4 [ILNP-v4opts]. ARP requires
enhancements to support ILNPv4 [ILNP-ENG].
If a node supports ILNP, and intends to receive incoming
sessions, the node's Fully-Qualified Domain Name (FQDN) normally
will have one or more ID records and one or more Locator
(i.e. L32, L64, and/or LP) records associated with the node
within the DNS [ILNP-ENG] [ILNP-DNS].
When a host ("initiator") initiates a new IP session with a
correspondent ("responder"), it normally will perform a DNS
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lookup to determine the address(es) of the responder. An ILNP
host normally will look for Identifier ("ID") and Locator
(i.e. L32, L64, and LP) records in any received DNS replies. DNS
servers that support ID and Locator (i.e. L32, L64, and LP)
records SHOULD include them (when they exist) as additional data
in all DNS replies to queries for DNS AAAA records [ILNP-DNS].
If the initiator supports ILNP, and from DNS information learns
that the responder also supports ILNP, then the initiator will
generate an unpredictable nonce value, cache that value locally
as part of the session, and will include the ILNP Nonce value in
its initial packet(s) to the responder [ILNP-ENG] [ILNP-NONCE6]
[ILNP-v4opts].
If the initiator node does not find any ILNP-specific DNS
resource records for the responder node, then the initiator uses
classic IP for the new session with the responder, rather than
trying to use ILNP for that session. Of course, multiple
transport-layer sessions can concurrently share a single
network-layer (e.g. IP or ILNP) session.
If the responder node for a new IP session does not support ILNP
and the responder node receives initial packet(s) containing the
ILNP Nonce, the responder will drop the packet and send an ICMP
error message back to the initiator. If the responder node for a
new IP session supports ILNP and receives initial packet(s)
containing the ILNP Nonce, the responder learns that ILNP is in
use for that session (i.e. by the presence of that ILNP Nonce).
If the initiator node using ILNP does not receive a response from
the responder in a timely manner (e.g. within TCP timeout for a
TCP session) and also does not receive an ICMP Unreachable error
message for that packet, OR if the initiator receives an ICMP
Parameter Problem error message for that packet, then the
initiator concludes that the responder does not support ILNP. In
this case, the initiator node SHOULD try again to create the new
session, but this time using IP (and therefore omitting the ILNP
Nonce).
Finally, since an ILNP node is also a fully-capable IP node, then
the upgraded node can use any standardised IP mechanisms for
communicating with a legacy IP-only node. So ILNP will not be
worse than existing IP, but when ILNP is used the enhanced
functionality described in this document will be useable.
9. SECURITY CONSIDERATIONS
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This proposal outlines a proposed evolution for the Internet
Architecture to provide improved capabilities. This section
discusses security considerations for this proposal.
Note that ILNP provides security equivalent to IP for similar
threats when similar mitigations (e.g. IPsec or not) are in
use. In some cases, but not all, ILNP exceeds that objective and
has lower security risk than IP. Additional engineering details
for several of these topics can be found in [ILNP-ENG].
9.1 Authentication of Locator Updates
All Locator Update messages are authenticated. ILNP requires
use of a session nonce [ILNP-NONCE6] [ILNP-v4opts] to prevent
off-path attacks, and also allows use of IPsec cryptography to
provide stronger protection where required.
Ordinary IP sessions are vulnerable to on-path attacks unless IP
Security is used. So the Nonce Destination Option only seeks to
provide protection against off-path attacks on an IP session --
equivalent to ordinary IP sessions when not using IP Security.
It is common to have non-symmetric paths between two nodes on the
Internet. To reduce the number of on-path nodes that know the
Nonce value for a given session when ILNP is in use, a nonce
value is unidirectional, not bidirectional. For example, for a
session between nodes A and B, one nonce value is used from A to
B and a different nonce value is used from B to A.
ILNP sessions operating in higher risk environments SHOULD also
use the cryptographic authentication provided by IP Security *in
addition* to concurrent use of the ILNP Nonce.
It is important to note that at present an IP session is entirely
vulnerable to on-path attacks unless IPsec is in use for that
particular IP session, so the security properties of the new
proposal are never worse than for existing IP.
9.2 Forged Identifier Attacks
In the deployed Internet, active attacks using packets with a
forged Source IP Address have been publicly known at least since
early 1995 [CA-1995-01]. While these exist in the deployed
Internet, they have not been widespread. This is equivalent to
the issue of a forged Identifier value and demonstrates that this
is not a new threat created by ILNP.
One mitigation for these attacks has been to deploy Source IP
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Address Filtering [RFC2827] [RFC3704]. Jun Bi at U. Tsinghua
cites Arbor Networks as reporting that this mechanism has less
than 50% deployment and cites an MIT analysis indicating that at
least 25% of the deployed Internet permits forged source IP
addresses.
In an other document [ILNP-ENG] there is a discussion of an
accidental use of a duplicate Identifier on the
Internet. However, this sub-section instead focuses on methods
for mitigating attacks based on packets containing deliberately
forged Source Identifier values.
Firstly, the recommendations of [RFC2827] & [RFC3704] remain.
So any packets that have a forged Locator value can be easily
filtered using existing widely available mechanisms.
Secondly, the receiving node does not blindly accept any packet
with the proper Source Identifier and proper Destination
Identifier as an authentic packet. Instead, each ILNP node
maintains an ILNP Correspondent Cache (ILCC) for each of its
correspondents, as described in [ILNP-ENG]. Information in the
cache is used in validating received messages and preventing
off-path attackers from succeeding. This process is discussed
more in [ILNP-ENG]
Thirdly, any node can distinguish different nodes using the same
Identifier value by other properties of their sessions. For
example, IPv6 Neighbor Discovery prevents more than one node from
using the same source IL-V at the same time on the same link. So
cases of different nodes using the same Identifier value will
involve nodes that have different sets of valid Locator values. A
node thus can demultiplex based on the combination of Source
Locator and Source Identifier if necessary. If IP Security is in
use, the combination of the Source Identifier and the SPI value
would be sufficient to demux two different sessions.
Fourthly, deployments in high threat environments also SHOULD use
IP Security to authenticate control traffic and data
traffic. Because IP Security for ILNP binds only to the
Identifier values, and never to the Locator values, a mobile or
multi-homed node can use IPsec even when its Locator value(s)
have just changed.
Lastly, note well that ordinary IPv4, ordinary IPv6, Mobile IPv4,
and also Mobile IPv6 already are vulnerable to forged Identifier
and/or forged IP address attacks. An attacker on the same link as
the intended victim simply forges the victims MAC address and the
victim's IP address. With IPv6, when Secure Neighbour Discovery
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(SEND) and Cryptographically Generated Addresses (CGAs) are in
use, the victim node can defend its use of its IPv6 address using
SEND. With ILNP, when SEND and CGAs are in use, the victim node
also can defend its use of its IPv6 address using SEND. There are
no standard mechanisms to authenticate ARP messages, so IPv4 is
especially vulnerable to this sort of attack. These attacks also
work against Mobile IPv4 and Mobile IPv6. In fact, when either
form of Mobile IP is in use, there are additional risks, because
the attacks work not only when the attacker has access to the
victim's current IP subnetwork but also when the attacker has
access to the victim's home IP subnetwork. So the risks of using
ILNP are not greater than exist today with IP or Mobile IP.
9.3 IP Security Enhancements
The IP Security standards are enhanced here by binding IPsec
Security Associations (SAs) to the Identifiers of the session
endpoints, rather than binding IPsec SAs to the IP Addresses as
at present. This change enhances the deployability and
interoperability of the IP Security standards, but does not
decrease the security provided by those protocols.
Also, the IP Authentication Header omits the Source Locator and
Destination Locator fields from its authentication calculations
when ILNP is in use. This enables IP AH to work well even through
a NAT or other situation where a Locator value might change
during transit.
9.4 DNS Security
The DNS enhancements proposed here are entirely compatible with,
and can be protected using, the existing IETF standards for DNS
Security [RFC4033]. The Secure DNS Dynamic Update mechanism used
here is also used unchanged [RFC3007]. So ILNP does not change
the security properties of the DNS or of DNS servers.
9.5 Firewall Considerations
In the proposed new scheme, stateful firewalls are able to
authenticate ICMP control messages arriving on the external
interface. This enables more thoughtful handling of ICMP messages
by firewalls than is commonly the case at present. As the
firewall is along the path between the communicating nodes, the
firewall can snoop on the Session Nonce being carried in the
initial packets of an ILNP session. The firewall can verify the
correct nonce is present on incoming control packets, dropping
any control packets that lack the correct nonce value.
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By always including the nonce in ILNP control messages, even when
IP Security is also in use, the firewall can filter out off-path
attacks against those ILNP messages. In any event, a forged
packet from an on-path attacker will still be detected when the
IPsec input processing occurs in the receiving node; this will
cause that forged packet to be dropped rather than acted upon.
9.6 Neighbour Discovery Authentication
Nothing in this proposal prevents sites from using the Secure
Neighbour Discovery (SEND) proposal for authenticating IPv6
Neighbour Discovery with ILNPv6 [RFC3971].
9.7 Site Topology Obfuscation
A site that wishes to obscure its internal topology information
MAY do so by deploying site border routers that rewrite the
Locator values for the site as packets enter or leave the
site. This operational scenario is discussed in more detail in
[ILNP-ADV].
For example, a site might choose to use a ULA prefix internally
for this reason [RFC4193] [ID-ULA]. In this case, the site border
routers would rewrite the Source Locator of ILNP packets leaving
the site to a global-scope Locator associated with the
site. Also, those site border routers would rewrite the
Destination Locator of packets entering the site from the
global-scope Locator to an appropriate interior ULA Locator for
the destination node [MILCOM08] [ILNP-ADV].
10. PRIVACY CONSIDERATIONS
Some users have concerns about the issue of "location privacy",
whereby the user's location might be determined by others. The
term "location privacy" does not have a crisp definition within
the Internet community at present. Some mean the location of a
node relative to the Internet's routing topology, while others
mean the geographic coordinates of the node (i.e. latitude X,
longitude Y). The concern seems to focus on Internet-enabled
devices, most commonly handheld devices such as a "smart phone",
that might have 1:1 mappings with individual users.
There is a fundamental trade-off here. Quality of a node's
Internet connectivity tends to be inversely proportional to the
"location privacy" of that node. For example, if a node were to
use a router with NAT as a privacy proxy, routing all traffic to
and from the Internet via that proxy, then (a) latency will
increase as the distance increases between the node seeking
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privacy and its proxy, and (b) communications with the node
seeking privacy will be more vulnerable to communication faults
-- both due to the proxy itself (which might fail) and due to the
longer path (which has more points of potential failure than a
more direct path would have).
Any Internet node that wishes for other Internet nodes to be able
to initiate communications sessions with it needs to include
associated address (e.g. A, AAAA) or Locator (e.g. L32, L64, LP)
records in the publicly accessible Domain Name System
(DNS). Information placed in the DNS is publicly
accessible. Since the goal of DNS is to distribute information to
other Internet nodes, it does not provide mechanisms for
selective privacy. Of course, a node that does not wish to be
contacted need not be present in the DNS.
In some cases, various parties have attempted to create mappings
between IP address blocks and geographic locations. The quality
of such mappings appears to vary [GUF07]. Many such mapping
efforts are driven themselves by efforts to comply with legal
requirements in various legal jurisdictions. For example, some
content providers reportedly have licenses authorising
distribution of content in one set of locations, but not in a
different set of locations.
ILNP does not compromise user location privacy any more than base
IPv6. In fact, by its nature ILNP provides additional choices to
the user to protect their location privacy. Both ILNP and IPv6
permit use of identifier values generated using the IPv6 Privacy
Address extension [RFC4941]. ILNP and IPv6 also support a node
having multiple unicast addresses/locators at the same time,
which facilitates changing the node's addresses/locators over
time. IPv4 does not have any non-topological identifiers, and
many IPv4 nodes only support 1 IPv4 unicast address per
interface, so IPv4 is not directly comparable with IPv6 or ILNP.
In normal operation with IPv4, IPv6, or ILNP, a mobile node might
intend to be accessible for new connection attempts from the
global Internet and also might wish to have both optimal routing
and maximal Internet availability, both for sent and received
packets. In that case, the node will want to have its addressing
or location information kept in the DNS and made available to
others.
In some cases, a mobile node might only desire to initiate
communications sessions with other Internet nodes, in which case
the node need not be present in the DNS. Some potential
correspondent nodes might, as a matter of local security policy,
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decline to communicate with nodes that do not have suitable DNS
records present in the DNS. For example, some deployed
IPv4-capable mail relays refuse to communicate with an initiating
node that lacks an appropriate PTR record in the DNS.
In some cases, for example intermittent electronic mail access or
browsing specific web pages, support for long-lived network
sessions (i.e. where session lifetime is longer than the time the
node remains on the same subnetwork) is not required. In those
cases, support for node mobility (i.e. session continuity even
when the SNPA changes) is not required and need not be used.
If an ILNP node that is mobile chooses not to use DNS for
rendezvous, yet desires to permit any node on the global Internet
to initiate communications with that node, then that node can
fall back to using Mobile IPv4 or Mobile IPv6 instead.
Many residential broadband Internet users are subject to
involuntary renumbering, usually when their ISP's DHCP server(s)
deny a DHCP RENEW request and instead issue different IP
addressing information to the residential user's device(s). In
many cases, such users want their home server(s) or client(s) to
be externally reachable. Such users today often use Secure DNS
Dynamic Update to update their addressing or location information
in the DNS entries, for the devices they wish to make reachable
from the global Internet [RFC2136] [RFC3007]. This option exists
for those users, whether they use IPv4, IPv6, or ILNP. Users
also have the option not to use such mechanisms.
11. IANA CONSIDERATIONS
This document has no IANA considerations.
(Note to RFC Editor; this section can be removed prior to
publication as an RFC.)
12. REFERENCES
This section provides normative and informative references
relating to this note.
12.1. Normative References
[RFC768] J. Postel, "User Datagram Protocol", RFC-768,
August 1980.
[RFC793] J. Postel, "Transmission Control Protocol",
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RFC-793, September 1981.
[RFC826] D. Plummer, "Ethernet Address Resolution Protocol:
Or Converting Network Protocol Addresses to
48 bit Ethernet Address for Transmission on
Ethernet Hardware", RFC 826, November 1982.
[RFC2119] Bradner, S., "Key words for use in RFCs to
Indicate Requirement Levels", BCP 14, RFC 2119,
March 1997.
[RFC2460] S. Deering & R. Hinden, "Internet Protocol
Version 6 Specification", RFC-2460,
December 1998.
[RFC3007] B. Wellington, "Secure Domain Name System
Dynamic Update", RFC-3007, November 2000.
[RFC3484] R. Draves, "Derfault Address Selection for IPv6",
RFC 3484, February 2003.
[RFC4033] R. Arends, et alia, "DNS Security Introduction
and Requirements", RFC-4033, March 2005.
[RFC4219] R. Hinden & S. Deering, "IP Version 6
Addressing Architecture", RFC-4219,
February 2006.
[RFC4861] T. Narten, E. Nordmark, W. Simpson, & H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)",
RFC 4861, September 2007.
[ILNP-ENG] R. Atkinson & S. Bhatti, "ILNP Engineering and
Implementation Considerations",
draft-irtf-rrg-ilnp-eng, January 2012.
[ILNP-DNS] R. Atkinson, S. Bhatti, & Rose, "DNS Resource
Records for ILNP", draft-irtf-rrg-ilnp-dns,
January 2012.
[ILNP-ICMPv4] R. Atkinson, "ICMPv4 Locator Update message"
draft-irtf-rrg-ilnp-icmpv4, January 2012.
[ILNP-ICMPv6] R. Atkinson, "ICMPv6 Locator Update message"
draft-irtf-rrg-ilnp-icmpv6, January 2012.
[ILNP-NONCE6] R. Atkinson & S. Bhatti, "IPv6 Nonce Destination
Option for ILNPv6", draft-irtf-rrg-ilnp-nonce6,
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January 2012.
[ILNP-v4opts] R. Atkinson & S. Bhatti, "IPv4 Options for ILNP",
draft-irtf-rrg-ilnp-v4opts, January 2012.
12.2. Informative References
[8+8] M. O'Dell, "8+8 - An Alternate Addressing
Architecture for IPv6", Internet-Draft,
October 1996.
[BA2011] S. Bhatti & R. Atkinson, "Reducing DNS Caching",
Proc. GI2011 - 14th IEEE Global Internet Symposium.
Shanghai, China. 15 April 2011.
[CA-1995-01] US CERT, "IP Spoofing Attacks and Hijacked
Terminal Connections", CERT Advisory 1995-01,
Issued 23 JAN 1995, Revised 23 SEP 1997.
[GSE] M. O'Dell, "GSE - An Alternate Addressing
Architecture for IPv6", Internet-Draft,
February 1997.
[ID-ULA] R. Hinden, G. Huston, & T. Narten, "Centrally
Assigned Unique Local IPv6 Unicast Addresses",
draft-ietf-ipv6-ula-central-02.txt, 15 June 2007.
[ID-Referral] B. Carpenter and others, "A Generic Referral
Object for Internet Entities",
draft-carpenter-behave-referral-object-01,
20 October 2009.
[IEEE-EUI] IEEE Standards Association, "Guidelines for
64-bit Global Identifier (EUI-64)", IEEE,
2007.
[IEN1] C.J. Bennett, S.W. Edge, & A.J. Hinchley,
"Issues in the Interconnection of Datagram
Networks", Internet Experiment Note (IEN) 1,
INDRA Note 637, PSPWN 76, University College
London, London, England, UK, WC1E 6BT,
29 July 1977.
http://www.postel.org/ien/ien001.pdf
[IEN19] J. F. Shoch, "Inter-Network Naming, Addressing,
and Routing", IEN-19, January 1978.
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[IEN23] J. F. Shoch, "On Names, Addresses, and
Routings", IEN-23, January 1978.
[IEN31] D. Cohen, "On Names, Addresses, and Routings
(II)", IEN-31, April 1978.
[ILNP-ADV]
[IPng95] D. Clark, "A thought on addressing",
electronic mail message to IETF IPng WG,
Message-ID: 9501111901.AA28426@caraway.lcs.mit.edu,
Laboratory for Computer Science, MIT,
Cambridge, MA, USA, 11 January 1995.
[Liu-DNS] C. Liu & P. Albitz, "DNS & Bind", 5th Edition,
O'Reilly & Associates, Sebastopol, CA, USA,
May 2006. ISBN 0-596-10057-4
[MobiArch07] R. Atkinson, S. Bhatti, & S. Hailes,
"Mobility as an Integrated Service Through
the Use of Naming", Proceedings of
ACM MobiArch 2007, August 2007,
Kyoto, Japan.
[MobiArch08] R. Atkinson, S. Bhatti, & S. Hailes,
"Mobility Through Naming: Impact on DNS",
Proceedings of ACM MobiArch 2008, August 2008,
Seattle, WA, USA.
[MobiWAC07] R. Atkinson, S. Bhatti, & S. Hailes,
"A Proposal for Unifying Mobility with
Multi-Homing, NAT, & Security",
Proceedings of ACM MobiWAC 2007, Chania,
Crete. ACM, October 2007.
[MILCOM08] R. Atkinson, S. Bhatti, & S. Hailes,
"Harmonised Resilience, Security, and Mobility
Capability for IP", Proceedings of IEEE
Military Communications (MILCOM) Conference,
San Diego, CA, USA, November 2008.
[MILCOM09] R. Atkinson, S. Bhatti, & S. Hailes,
"Site-Controlled Secure Multi-Homing and
Traffic Engineering For IP", Proceedings of
IEEE Military Communications (MILCOM) Conference,
Boston, MA, USA, October 2009.
[PHG02] A. Pappas, S. Hailes, & R. Giaffreda,
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"Mobile Host Location Tracking through DNS",
Proceedings of IEEE London Communications
Symposium, IEEE, September 2002, London,
England, UK.
[SBK2002] Alex C. Snoeren, Hari Balakrishnan, & M. Frans
Kaashoek, "Reconsidering Internet Mobility",
Proceedings of 8th Workshop on Hot Topics in
Operating Systems, 2002.
[SIPP94] Bob Smart, "Re: IPng Directorate meeting in
Chicago; possible SIPP changes", electronic
mail to the IETF SIPP WG mailing list,
Message-ID:
199406020647.AA09887@shark.mel.dit.csiro.au,
Commonwealth Scientific & Industrial Research
Organisation (CSIRO), Melbourne, VIC, 3001,
Australia, 2 June 1994.
[SRC84] J. Saltzer, D. Reed, & D. Clark, "End to End
Arguments in System Design", remainder TBD
[RFC814] D.D. Clark, "Names, Addresses, Ports, and
Routes", RFC-814, July 1982.
[RFC1498] J.H. Saltzer, "On the Naming and Binding of
Network Destinations", RFC-1498, August 1993.
[RFC1631] K. Egevang & P. Francis, "The IP Network
Address Translator (NAT)", RFC-1631, May 1994.
[RFC1958]
[RFC1992]
[RFC2101]
[RFC2136]
[RFC2827] P. Ferguson & D. Senie, "Network Ingress Filtering:
Defeating Denial of Service Attacks which employ
IP Source Address Spoofing", RFC-2827, May 2000.
[RFC2956]
[RFC3177]
[RFC3022] P. Srisuresh & K. Egevang, "Traditional IP
Atkinson & Bhatti Expires in 6 months [Page 44]
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Network Address Translator", RFC-3022,
January 2001.
[RFC3027] M. Holdrege and P Srisuresh, "Protocol
Complications of the IP Network Address
Translator", RFC-3027, January 2001.
[RFC3704] F. Baker & P. Savola, "Ingress Filtering for
Multihomed Networks, RFC-3704, March 2004.
[RFC3715] B. Aboba and W. Dixon, "IPsec-Network Address
Translation (NAT) Compatibility Requirements",
RFC-3715, March 2004.
[RFC3775] D. Johnson, C. Perkins, and J. Arkko, "Mobility
Support in IPv6", RFC-3775, June 2004.
[RFC3948] A. Huttunen, et alia, "UDP Encapsulation of
IPsec ESP Packets", RFC-3948, January 2005.
[RFC3971] J. Arkko, J. Kempf, B. Zill, & P. Nikander,
"SEcure Neighbor Discovery (SEND)", RFC-3971
March 2005.
[RFC3972] T. Aura, "Cryptographically Generated Addresses
(CGAs)", RFC-3972, March 2005.
[RFC4193] R. Hinden & B. Haberman, "Unique Local IPv6
Unicast Addresses, RFC-4193, October 2005.
[RFC4291]
[RFC4581]
[RFC4941] T. Narten, R. Draves, & S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration
in IPv6", RFC-4941, September 2007.
[RFC4982]
[RFC4984]
[RFC5061] R. Stewart, Q. Xie, M. Tuexen, S. Maruyama, &
M. Kozuka, "Stream Control Transmission Protocol
(SCTP) Dynamic Address Reconfiguration", RFC-5061,
September 2007.
[RFC5534] J. Arkko & I. van Beijnum, "Failure Detection
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and Locator Pair Exploration Protocol for IPv6
Multihoming", RFC-5534, June 2009.
[RFC6177]
[TeleSys] R. Atkinson, S. Bhatti, & S. Hailes, "ILNP: Mobility,
Multi-Homing, Localised Addressing and Security
Through Naming", Telecommunications Systems,
Volume 42, Number 3-4, pp 273-291,
Springer-Verlag, December 2009, ISSN 1018-4864.
[GUF07] B. Gueye, S. Uhlig, & S. Fdida, "Investigating the
Imprecision of IP Block-Based Geolocation",
Lecture Notes in Computer Science, Volume 4427,
pp. 237-240, Springer-Verlag, Heidelberg,
Germany, 2007.
ACKNOWLEDGEMENTS
Steve Blake, Mohamed Boucadair, Noel Chiappa, Steve Hailes, Joel
Halpern, Mark Handley, Volker Hilt, Paul Jakma, Dae-Young Kim,
Tony Li, Yakov Rehkter, Robin Whittle and John Wroclawski (in
alphabetical order) provided review and feedback on earlier
versions of this document. Steve Blake provided an especially
thorough review of an early version of the entire ILNP document
set, which was extremely helpful. We also wish to thank the
anonymous reviewers of the various ILNP papers for their
feedback.
Noel Chiappa graciously provided the authors with copies of the
original email messages cited here as [SIPP94] and [IPng95],
which enabled the precise citation of those messages herein.
Author's Address
RJ Atkinson
Consultant
San Jose, CA
95125 USA
Email: rja.lists@gmail.com
SN Bhatti
School of Computer Science
University of St Andrews
North Haugh, St Andrews
Fife, Scotland
KY16 9SX, UK
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Email: saleem@cs.st-andrews.ac.uk
Expires: 09 JUL 2012
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