Extensions to Generic Aggregate RSVP for IPv4 and IPv6 Reservations over Pre-Congestion Notification (PCN) Domains
RFC 7417
| Document | Type | RFC - Experimental (December 2014; No errata) | |
|---|---|---|---|
| Authors | Georgios Karagiannis , Anurag Bhargava | ||
| Last updated | 2015-10-14 | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text html pdf htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | David Black | ||
| Shepherd write-up | Show (last changed 2014-09-19) | ||
| IESG | IESG state | RFC 7417 (Experimental) | |
| Action Holders |
(None)
|
||
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Spencer Dawkins | ||
| Send notices to | (None) | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA action state | RFC-Ed-Ack | ||
Internet Engineering Task Force (IETF) G. Karagiannis
Request for Comments: 7417 Huawei Technologies
Category: Experimental A. Bhargava
ISSN: 2070-1721 Cisco Systems, Inc.
December 2014
Extensions to Generic Aggregate RSVP for IPv4 and IPv6 Reservations
over Pre-Congestion Notification (PCN) Domains
Abstract
This document specifies extensions to Generic Aggregate RSVP (RFC
4860) for support of the Pre-Congestion Notification (PCN) Controlled
Load (CL) and Single Marking (SM) edge behaviors over a Diffserv
cloud using PCN.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for examination, experimental implementation, and
evaluation.
This document defines an Experimental Protocol for the Internet
community. This document is a product of the Internet Engineering
Task Force (IETF). It represents the consensus of the IETF
community. It has received public review and has been approved for
publication by the Internet Engineering Steering Group (IESG). Not
all documents approved by the IESG are a candidate for any level of
Internet Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7417.
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Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
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Table of Contents
1. Introduction ....................................................4
1.1. Objective ..................................................4
1.2. Overview and Motivation ....................................5
1.3. Requirements Language and Terminology ......................8
1.4. Organization of This Document .............................12
2. Overview of RSVP Extensions and Operations .....................12
2.1. Overview of RSVP Aggregation Procedures in PCN-Domains ....12
2.2. PCN-Marking, Encoding, and Transport of
Pre-congestion Information ................................14
2.3. Traffic Classification within the Aggregation Region ......14
2.4. Deaggregator (PCN-Egress-Node) Determination ..............15
2.5. Mapping E2E Reservations onto Aggregate Reservations ......15
2.6. Size of Aggregate Reservations ............................16
2.7. E2E Path ADSPEC Update ....................................16
2.8. Intra-domain Routes .......................................16
2.9. Inter-domain Routes .......................................16
2.10. Reservations for Multicast Sessions ......................16
2.11. Multi-level Aggregation ..................................16
2.12. Reliability Issues .......................................17
3. Elements of Procedures .........................................17
3.1. Receipt of E2E Path Message by PCN-Ingress-Node
(Aggregating Router) ......................................17
3.2. Handling of E2E Path Message by Interior Routers ..........17
3.3. Receipt of E2E Path Message by PCN-Egress-Node
(Deaggregating Router) ....................................18
3.4. Initiation of New Aggregate Path Message by
PCN-Ingress-Node (Aggregating Router) .....................18
3.5. Handling of Aggregate Path Message by Interior Routers ....18
3.6. Handling of Aggregate Path Message by
Deaggregating Router ......................................18
3.7. Handling of E2E Resv Message by Deaggregating Router ......19
3.8. Handling of E2E Resv Message by Interior Routers ..........19
3.9. Initiation of New Aggregate Resv Message by
Deaggregating Router ......................................20
3.10. Handling of Aggregate Resv Message by Interior Routers ...20
3.11. Handling of E2E Resv Message by Aggregating Router .......21
3.12. Handling of Aggregate Resv Message by
Aggregating Router .......................................21
3.13. Removal of E2E Reservation ...............................21
3.14. Removal of Aggregate Reservation .........................22
3.15. Handling of Data on Reserved E2E Flow by
Aggregating Router .......................................22
3.16. Procedures for Multicast Sessions ........................22
3.17. Misconfiguration of PCN-Node .............................22
3.18. PCN-Based Flow Termination ...............................22
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4. Protocol Elements ..............................................23
4.1. PCN Objects ...............................................24
5. Security Considerations ........................................28
6. IANA Considerations ............................................29
7. References .....................................................29
7.1. Normative References ......................................29
7.2. Informative References ....................................30
Appendix A. Example Signaling Flow ................................33
Acknowledgments ...................................................35
Authors' Addresses ................................................36
1. Introduction
1.1. Objective
Pre-Congestion Notification (PCN) can support the Quality of Service
(QoS) of inelastic flows within a Diffserv domain in a simple,
scalable, and robust fashion. Two mechanisms are used: admission
control and flow termination. Admission control is used to decide
whether to admit or block a new flow request, while flow termination
is used in abnormal circumstances to decide whether to terminate some
of the existing flows. To support these two features, the overall
rate of PCN-traffic is metered on every link in the domain, and
PCN-packets are appropriately marked when certain configured rates
are exceeded. These configured rates are below the rate of the link,
thus providing notification to boundary nodes about overloads before
any congestion occurs (hence "pre-congestion" notification). The
PCN-egress-nodes measure the rates of differently marked PCN-traffic
in periodic intervals and report these rates to the Decision Points
for admission control and flow termination; the Decision Points use
these rates to make decisions. The Decision Points may be collocated
with the PCN-ingress-nodes, or their function may be implemented in
another node. For more details, see [RFC5559], [RFC6661], and
[RFC6662].
The main objective of this document is to specify the signaling
protocol that can be used within a PCN-domain to carry reports from a
PCN-ingress-node to a PCN Decision Point, considering that the PCN
Decision Point and PCN-egress-node are collocated.
If the PCN Decision Point is not collocated with the PCN-egress-node,
then additional signaling procedures are required that are out of
scope for this document. Moreover, as mentioned above, this
architecture conforms with Policy-Based Admission Control (PBAC),
where the Decision Point is located in a node other than the
PCN-ingress-node [RFC2753].
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Several signaling protocols can be used to carry information between
PCN-boundary-nodes (PCN-ingress-node and PCN-egress-node). However,
since (1) both the PCN-egress-node and PCN-ingress-node are located
on the data path and (2) the admission control procedure needs to be
done at the PCN-egress-node, a signaling protocol that follows the
same path as the data path, like RSVP, is more suited for this
purpose. In particular, this document specifies extensions to
Generic Aggregate RSVP [RFC4860] for support of the PCN Controlled
Load (CL) and Single Marking (SM) edge behaviors over a Diffserv
cloud using Pre-Congestion Notification.
This document is published as an Experimental document in order to:
o validate industry interest by allowing implementation and
deployment
o gather operational experience, particularly related to dynamic
interactions of RSVP signaling and PCN, and corresponding levels
of performance
Support for the techniques specified in this document involves RSVP
functionality in boundary nodes of a PCN-domain whose interior nodes
forward RSVP traffic without performing RSVP functionality.
1.2. Overview and Motivation
Two main QoS architectures have been specified by the IETF: the
Integrated Services (Intserv) [RFC1633] architecture and the
Differentiated Services (Diffserv) architecture ([RFC2475]).
Intserv provides methods for the delivery of end-to-end QoS to
applications over heterogeneous networks. One of the QoS signaling
protocols used by the Intserv architecture is RSVP [RFC2205], which
can be used by applications to request per-flow resources from the
network. These RSVP requests can be admitted or rejected by the
network. Applications can express their quantifiable resource
requirements using Intserv parameters as defined in [RFC2211] and
[RFC2212]. The Controlled Load (CL) service [RFC2211] is a form of
QoS that closely approximates the QoS that the same flow would
receive from a lightly loaded network element. The CL service is
useful for inelastic flows such as those used for real-time media.
The Diffserv architecture can support the differentiated treatment of
packets in very large-scale environments. While Intserv and RSVP
classify packets per flow, Diffserv networks classify packets into
one of a small number of aggregated flows or "classes", based on the
Diffserv Codepoint (DSCP) in the packet IP header. At each Diffserv
router, packets are subjected to a "Per Hop Behavior" (PHB), which is
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invoked by the DSCP. The primary benefit of Diffserv is its
scalability, since the need for per-flow state and per-flow
processing is eliminated.
However, Diffserv does not include any mechanism for communication
between applications and the network. Several solutions have been
specified to solve this issue. One of these solutions is Intserv
over Diffserv [RFC2998], including Resource-Based Admission Control
(RBAC), PBAC, assistance in traffic identification/classification,
and traffic conditioning. Intserv over Diffserv can operate over a
statically provisioned or an RSVP-aware Diffserv region. When it is
RSVP aware, several mechanisms may be used to support dynamic
provisioning and topology-aware admission control, including
aggregate RSVP reservations, per-flow RSVP, or a bandwidth broker.
[RFC3175] specifies aggregation of RSVP end-to-end reservations over
aggregate RSVP reservations. In [RFC3175], the RSVP generic
aggregate reservation is characterized by an RSVP SESSION object
using the 3-tuple <source IP address, destination IP address,
Diffserv Codepoint>.
Several scenarios require the use of multiple generic aggregate
reservations that are established for a given PHB from a given source
IP address to a given destination IP address; see [RFC4923] and
[RFC4860]. For example, multiple generic aggregate reservations can
be applied in situations where multiple end-to-end (E2E) reservations
using different preemption priorities need to be aggregated through a
PCN-domain using the same PHB. Using multiple aggregate reservations
for the same PHB allows
o enforcement of the different preemption priorities within the
aggregation region
o more efficient management of Diffserv resources
o sustainment of a larger number of E2E reservations with higher
preemption priorities during periods of resource shortage
In particular, [RFC4923] discusses in detail how end-to-end RSVP
reservations can be established in a nested VPN environment through
RSVP aggregation.
[RFC4860] provides generic aggregate reservations by extending
[RFC3175] to support multiple aggregate reservations for the same
source IP address, destination IP address, and PHB (or set of PHBs).
In particular, multiple such generic aggregate reservations can be
established for a given PHB from a given source IP address to a given
destination IP address. This is achieved by adding the concept of a
Virtual Destination Port and an Extended Virtual Destination Port in
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the RSVP SESSION object. In addition to this, the RSVP SESSION
object for generic aggregate reservations uses the PHB Identification
Code (PHB-ID) defined in [RFC3140] instead of using the Diffserv
Codepoint (DSCP) used in [RFC3175]. The PHB-ID is used to identify
the PHB, or set of PHBs, from which the Diffserv resources are to be
reserved.
The RSVP-like signaling protocol required to carry (1) requests from
a PCN-egress-node to a PCN-ingress-node and (2) reports from a
PCN-ingress-node to a PCN-egress-node needs to follow the PCN
signaling requirements defined in [RFC6663]. In addition to that,
the signaling protocol functionality supported by the PCN-ingress-
nodes and PCN-egress-nodes needs to maintain logical aggregate
constructs (i.e., ingress-egress-aggregate state) and be able to map
E2E reservations to these aggregate constructs. Moreover, no actual
reservation state is needed to be maintained inside the PCN-domain,
i.e., the PCN-interior-nodes are not maintaining any reservation
state.
This can be accomplished by two possible approaches:
Approach (1):
o adapting the aggregation procedures of RFC 4860 to fit the PCN
requirements with as little change as possible over the
functionality provided in RFC 4860.
o hence, performing aggregate RSVP signaling (even if it is to be
ignored by PCN-interior-nodes).
o using the aggregate RSVP signaling procedures to carry PCN
information between the PCN-boundary-nodes (PCN-ingress-node and
PCN-egress-node).
Approach (2):
o adapting the aggregation procedures of RFC 4860 to fit the PCN
requirements with significant changes over RFC 4860 (i.e., the
aspect of the procedures that have to do with maintaining
aggregate states and mapping the E2E reservations to aggregate
constructs are kept, but the procedures that are specific to
aggregate RSVP signaling and aggregate reservation
establishment/maintenance are dropped).
o hence not performing aggregate RSVP signaling.
o piggybacking the PCN information inside the E2E RSVP signaling.
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Both approaches are probably viable; however, since the operations of
RFC 4860 have been thoroughly studied and implemented, it can be
considered that the solution from RFC 4860 can better deal with the
more challenging situations (rerouting in the PCN-domain, failure of
a PCN-ingress-node, failure of a PCN-egress-node, rerouting towards a
different edge, etc.). This is the reason for choosing Approach (1)
for the specification of the signaling protocol used to carry PCN
information between the PCN-boundary-nodes (PCN-ingress-node and
PCN-egress-node).
As noted earlier, this document specifies extensions to Generic
Aggregate RSVP [RFC4860] for support of the PCN Controlled Load (CL)
and Single Marking (SM) edge behaviors over a Diffserv cloud using
Pre-Congestion Notification.
This document follows the PCN signaling requirements defined in
[RFC6663] and specifies extensions to Generic Aggregate RSVP
[RFC4860] for support of PCN edge behaviors as specified in [RFC6661]
and [RFC6662]. Moreover, this document specifies how RSVP
aggregation can be used to set up and maintain (1) Ingress-Egress-
Aggregate (IEA) states at Ingress and Egress nodes and (2) generic
aggregation of end-to-end RSVP reservations over PCN (Congestion and
Pre-Congestion Notification) domains.
To comply with this specification, PCN-nodes MUST be able to support
the functionality specified in [RFC5670], [RFC5559], [RFC6660],
[RFC6661], and [RFC6662]. Furthermore, the PCN-boundary-nodes MUST
support the RSVP generic aggregate reservation procedures specified
in [RFC4860], which are augmented with procedures specified in this
document.
1.3. Requirements Language and 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 [RFC2119].
This document uses terms defined in [RFC4860], [RFC3175], [RFC5559],
[RFC5670], [RFC6661], and [RFC6662].
For readability, a number of definitions from [RFC3175] as well as
definitions for terms used in [RFC5559], [RFC6661], and [RFC6662] are
provided here, where some of them are augmented with new meanings:
Aggregator
The process in (or associated with) the router at the ingress edge
of the aggregation region (with respect to the end-to-end RSVP
reservation) and behaving in accordance with [RFC4860]. In this
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document, it is also the PCN-ingress-node. It is important to
notice that in the context of this document the Aggregator must be
able to determine the Deaggregator using the procedures specified
in Section 4 of [RFC4860] and Section 1.4.2 of [RFC3175].
Congestion Level Estimate (CLE)
The ratio of PCN-marked to total PCN-traffic (measured in octets)
received for a given ingress-egress-aggregate during a given
measurement period. The CLE is used to derive the PCN-admission-
state and is also used by the report suppression procedure if
report suppression is activated.
Deaggregator
The process in (or associated with) the router at the egress edge
of the aggregation region (with respect to the end-to-end RSVP
reservation) and behaving in accordance with [RFC4860]. In this
document, it is also the PCN-egress-node and Decision Point.
E2E
End to end
E2E Microflow
A microflow where its associated packets are being forwarded on an
E2E path.
E2E Reservation
An RSVP reservation such that:
(1) corresponding RSVP Path messages are initiated upstream of the
Aggregator and terminated downstream of the Deaggregator, and
(2) corresponding RSVP Resv messages are initiated downstream of
the Deaggregator and terminated upstream of the Aggregator,
and
(3) this RSVP reservation is aggregated over an Ingress-Egress-
Aggregate (IEA) between the Aggregator and Deaggregator.
An E2E RSVP reservation may be a per-flow reservation, which in
this document is only maintained at the PCN-ingress-node and
PCN-egress-node. Alternatively, the E2E reservation may itself be
an aggregate reservation of various types (e.g., Aggregate IP
reservation, Aggregate IPsec reservation [RFC4860]). As per
regular RSVP operations, E2E RSVP reservations are unidirectional.
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ETM-Rate
The rate of excess-traffic-marked (ETM) PCN-traffic received at a
PCN-egress-node for a given ingress-egress-aggregate in octets
per second.
Extended vDstPort (Extended Virtual Destination Port)
An identifier used in the SESSION that remains constant over the
life of the generic aggregate reservation. The length of this
identifier is 32 bits when IPv4 addresses are used and 128 bits
when IPv6 addresses are used.
A sender (or Aggregator) that wishes to narrow the scope of a
SESSION to the sender-receiver pair (or Aggregator-Deaggregator
pair) should place its IPv4 or IPv6 address here as a network
unique identifier. A sender (or Aggregator) that wishes to use a
common session with other senders (or Aggregators) in order to use
a shared reservation across senders (or Aggregators) must set this
field to all zeros. In this document, the Extended vDstPort
should contain the IPv4 or IPv6 address of the Aggregator.
Ingress-Egress-Aggregate (IEA)
The collection of PCN-packets from all PCN-flows that travel in
one direction between a specific pair of PCN-boundary-nodes. In
this document, one RSVP generic aggregate reservation is mapped to
only one ingress-egress-aggregate, while one ingress-egress-
aggregate is mapped to one or more RSVP generic aggregate
reservations. PCN-flows and their PCN-traffic that are mapped
into a specific RSVP generic aggregate reservation can also be
easily mapped into their corresponding ingress-egress-aggregate.
Microflow (from [RFC2474])
A single instance of an application-to-application flow of
packets, which is identified by <source address, destination
address, protocol id> and (where applicable) <source port,
destination port>.
PCN-Admission-State
The state ("admit" or "block") derived by the Decision Point for a
given ingress-egress-aggregate based on statistics about
PCN-packet marking. The Decision Point decides to admit or block
new flows offered to the aggregate based on the current value of
the PCN-admission-state.
PCN-Boundary-Node
A PCN-node that connects one PCN-domain to a node in either
another PCN-domain or a non-PCN-domain.
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PCN-Domain
A PCN-capable domain; a contiguous set of PCN-enabled nodes that
perform Diffserv scheduling [RFC2474]; the complete set of
PCN-nodes that in principle can, through PCN-marking packets,
influence decisions about flow admission and termination within
the domain; includes the PCN-egress-nodes, which measure these
PCN-marks, and the PCN-ingress-nodes.
PCN-Egress-Node
A PCN-boundary-node in its role in handling traffic as it leaves a
PCN-domain. In this document, the PCN-egress-node also operates
as a Decision Point and Deaggregator.
PCN-Flow
The unit of PCN-traffic that the PCN-boundary-node admits (or
terminates); the unit could be a single E2E microflow (as defined
in [RFC2474]) or some identifiable collection of microflows.
PCN-Ingress-Node
A PCN-boundary-node in its role in handling traffic as it enters a
PCN-domain. In this document, the PCN-ingress-node also operates
as an Aggregator.
PCN-Interior-Node
A node in a PCN-domain that is not a PCN-boundary-node.
PCN-Node
A PCN-boundary-node or a PCN-interior-node.
PCN-Sent-Rate
The rate of PCN-traffic received at a PCN-ingress-node and
destined for a given ingress-egress-aggregate in octets per
second.
PCN-Traffic, PCN-Packets, PCN-BA
A PCN-domain carries traffic of different Diffserv Behavior
Aggregates (BAs) [RFC2474]. The PCN-BA uses the PCN mechanisms to
carry PCN-traffic, and the corresponding packets are PCN-packets.
The same network will carry traffic of other Diffserv BAs. The
PCN-BA is distinguished by a combination of the Diffserv Codepoint
(DSCP) and Explicit Congestion Notification (ECN) fields.
PHB-ID (Per Hop Behavior Identification Code)
A 16-bit field containing the Per Hop Behavior Identification Code
of the PHB, or of the set of PHBs, from which Diffserv resources
are to be reserved. This field must be encoded as specified in
Section 2 of [RFC3140].
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RSVP Generic Aggregate Reservation
An RSVP reservation that is identified by using the RSVP SESSION
object for generic RSVP aggregate reservation. This RSVP SESSION
object is based on the RSVP SESSION object specified in [RFC4860],
augmented with the following information:
o The IPv4 DestAddress, IPv6 DestAddress should be set to the
IPv4 or IPv6 destination addresses, respectively, of the
Deaggregator (PCN-egress-node).
o The PHB-ID should be set equal to PCN-compatible Diffserv
Codepoint(s).
o The Extended vDstPort should be set to the IPv4 or IPv6
destination addresses, of the Aggregator (PCN-ingress-node).
VDstPort (Virtual Destination Port)
A 16-bit identifier used in the SESSION that remains constant over
the life of the generic aggregate reservation.
1.4. Organization of This Document
This document is organized as follows. Section 2 gives an overview
of RSVP extensions and operations. The elements of the procedures
that are used in this document are specified in Section 3. Section 4
describes the protocol elements. The security considerations are
given in Section 5, and the IANA considerations are provided in
Section 6.
2. Overview of RSVP Extensions and Operations
2.1. Overview of RSVP Aggregation Procedures in PCN-Domains
The PCN-boundary-nodes (see Figure 1) can support RSVP SESSIONS for
generic aggregate reservations [RFC4860], which depend on ingress-
egress-aggregates. In particular, one RSVP generic aggregate
reservation matches to only one ingress-egress-aggregate.
However, one ingress-egress-aggregate matches to one or more RSVP
generic aggregate reservations. In addition, to comply with this
specification, the PCN-boundary-nodes need to distinguish and process
(1) RSVP SESSIONS for generic aggregate sessions and their messages
according to [RFC4860] and (2) E2E RSVP SESSIONS and messages
according to [RFC2205].
This document locates all RSVP processing for a PCN-domain at
PCN-boundary-nodes. PCN-interior-nodes do not perform any RSVP
functionality or maintain RSVP-related state information. Rather,
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PCN-interior-nodes forward all RSVP messages (for both generic
aggregate reservations [RFC4860] and E2E reservations [RFC2205]) as
if they were ordinary network traffic.
Moreover, each Aggregator and Deaggregator (i.e., PCN-boundary-nodes)
needs to support policies to initiate and maintain, for each pair of
PCN-boundary-nodes of the same PCN-domain, one ingress-egress-
aggregate.
--------------------------
/ PCN-domain \
|----| | | |----|
H--| R |\ |-----| |------| /| R |-->H
H--| |\\| | |---| |---| | |//| |-->H
|----| \| | | I | | I | | |/ |----|
| Agg |======================>| Deag |
/| | | | | | | |\
H--------//| | |---| |---| | |\\-------->H
H--------/ |-----| |------| \-------->H
| |
\ /
--------------------------
H = Host requesting end-to-end RSVP reservations
R = RSVP router
Agg = Aggregator (PCN-ingress-node)
Deag = Deaggregator (PCN-egress-node)
I = Interior Router (PCN-interior-node)
--> = E2E RSVP reservation
==> = Aggregate RSVP reservation
Figure 1: Aggregation of E2E Reservations over Generic Aggregate
RSVP Reservations in PCN-Domains, Based on [RFC4860]
Both the Aggregator and Deaggregator can maintain one or more RSVP
generic aggregate reservations, but the Deaggregator is the entity
that initiates these RSVP generic aggregate reservations. Note that
one RSVP generic aggregate reservation matches to only one ingress-
egress-aggregate, while one ingress-egress-aggregate matches to one
or more RSVP generic aggregate reservations. This can be
accomplished by using for the different RSVP generic aggregate
reservations the same combinations of ingress and egress identifiers,
but with a different PHB-ID value (see [RFC4860]). The procedures
for aggregation of E2E reservations over generic aggregate RSVP
reservations are the same as the procedures specified in Section 4 of
[RFC4860], augmented with the ones specified in Section 2.5.
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One significant difference between this document and [RFC4860] is the
fact that in this document the admission control of E2E RSVP
reservations over the PCN-core is performed according to the PCN
procedures, while in [RFC4860] this is achieved via first admitting
aggregate RSVP reservations over the aggregation region and then
admitting the E2E reservations over the aggregate RSVP reservations.
Therefore, in this document, the RSVP generic aggregate RSVP
reservations are not subject to admission control in the PCN-core,
and the E2E RSVP reservations are not subject to admission control
over the aggregate reservations. In turn, this means that several
procedures described in [RFC4860] are significantly simplified in
this document:
o Unlike [RFC4860], the generic aggregate RSVP reservations need not
be admitted in the PCN-core.
o Unlike [RFC4860], the RSVP aggregated traffic does not need to be
tunneled between Aggregator and Deaggregator; see Section 2.3.
o Unlike [RFC4860], the Deaggregator need not perform admission
control of E2E reservations over the aggregate RSVP reservations.
o Unlike [RFC4860], there is no need for dynamic adjustment of the
RSVP generic aggregate reservation size; see Section 2.6.
2.2. PCN-Marking, Encoding, and Transport of Pre-congestion Information
The method of PCN-marking within the PCN-domain is specified in
[RFC5670]. In addition, the method of encoding and transport of
pre-congestion information is specified in [RFC6660]. The PHB-ID
(Per Hop Behavior Identification Code) used SHOULD be set equal to
PCN-compatible Diffserv Codepoint(s).
2.3. Traffic Classification within the Aggregation Region
The PCN-ingress marks a PCN-BA using PCN-marking (i.e., a combination
of the DSCP and ECN fields), which interior nodes use to classify
PCN-traffic. The PCN-traffic (e.g., E2E microflows) belonging to an
RSVP generic aggregate reservation can be classified only at the
PCN-boundary-nodes (i.e., Aggregator and Deaggregator) by using the
RSVP SESSION object for RSVP generic aggregate reservations; see
Section 2.1 of [RFC4860]. Note that the DSCP value included in the
SESSION object SHOULD be set equal to a PCN-compatible Diffserv
Codepoint. Since no admission control procedures over the RSVP
generic aggregate reservations in the PCN-core are required, unlike
[RFC4860], the RSVP aggregated traffic need not be tunneled between
Aggregator and Deaggregator. In this document, one RSVP generic
aggregate reservation is mapped to only one ingress-egress-aggregate,
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while one ingress-egress-aggregate is mapped to one or more RSVP
generic aggregate reservations. PCN-flows and their PCN-traffic that
are mapped into a specific RSVP generic aggregate reservation can
also easily be classified into their corresponding ingress-egress-
aggregate. The method of traffic conditioning of PCN-traffic and
non-PCN-traffic, as well as the method of PHB configuration, are
described in [RFC6661] and [RFC6662].
2.4. Deaggregator (PCN-Egress-Node) Determination
This document assumes the same dynamic Deaggregator determination
method as that used in [RFC4860].
2.5. Mapping E2E Reservations onto Aggregate Reservations
To comply with this specification, for the mapping of E2E
reservations onto aggregate reservations, the same methods MUST be
used as the ones described in Section 4 of [RFC4860], augmented by
the following rules:
o An Aggregator (PCN-ingress-node) or Deaggregator (PCN-egress-node
and Decision Point) MUST use one or more policies to determine
whether an RSVP generic aggregate reservation can be mapped into
an ingress-egress-aggregate. This can be accomplished by using
for the different RSVP generic aggregate reservations the same
combinations of ingress and egress identifiers, but with a
different PHB-ID value (see [RFC4860]) corresponding to the PCN
specifications -- in particular, the RSVP SESSION object specified
in [RFC4860], augmented with the following information:
o The IPv4 DestAddress, IPv6 DestAddress MUST be set to the IPv4
or IPv6 destination addresses, respectively, of the
Deaggregator (PCN-egress-node); see [RFC4860]. Note that the
PCN-domain is considered as being only one RSVP hop (for
generic aggregate RSVP or E2E RSVP). This means that the next
RSVP hop for the Aggregator in the downstream direction is the
Deaggregator and the next RSVP hop for the Deaggregator in the
upstream direction is the Aggregator.
o The PHB-ID (Per Hop Behavior Identification Code) SHOULD be set
equal to PCN-compatible Diffserv Codepoint(s).
o The Extended vDstPort SHOULD be set to the IPv4 or IPv6
destination addresses of the Aggregator (PCN-ingress-node); see
[RFC4860].
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2.6. Size of Aggregate Reservations
Since (1) no admission control of E2E reservations over the RSVP
aggregate reservations is required and (2) no admission control of
the RSVP aggregate reservation over the PCN-core is required, the
size of the generic aggregate reservation is irrelevant and can be
set to any arbitrary value by the Deaggregator. The Deaggregator
SHOULD set the value of a generic aggregate reservation to a null
bandwidth. We also observe that there is no need for dynamic
adjustment of the RSVP aggregate reservation size.
2.7. E2E Path ADSPEC Update
To comply with this specification, for the update of the E2E Path
ADSPEC, the same methods can be used as the ones described in
[RFC4860].
2.8. Intra-domain Routes
The PCN-interior-nodes maintain neither E2E RSVP nor RSVP generic
aggregation states and reservations. Therefore, intra-domain route
changes will not affect intra-domain reservations, since such
reservations are not maintained by the PCN-interior-nodes.
Furthermore, it is considered that by configuration the PCN-interior-
nodes can distinguish neither RSVP generic aggregate sessions and
their associated messages [RFC4860] nor E2E RSVP SESSIONS and their
associated messages [RFC2205].
2.9. Inter-domain Routes
The PCN-charter scope precludes inter-domain considerations.
However, for solving inter-domain route changes associated with the
operation of the RSVP messages, the same methods SHOULD be used as
the ones described in [RFC4860] and in Section 1.4.7 of [RFC3175].
2.10. Reservations for Multicast Sessions
PCN does not consider reservations for multicast sessions.
2.11. Multi-level Aggregation
PCN does not consider multi-level aggregations within the PCN-domain.
Therefore, the PCN-interior-nodes do not support multi-level
aggregation procedures. However, the Aggregator and Deaggregator
SHOULD support the multi-level aggregation procedures specified in
[RFC4860] and in Section 1.4.9 of [RFC3175].
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2.12. Reliability Issues
To comply with this specification, for solving possible reliability
issues, the same methods MUST be used as the ones described in
Section 4 of [RFC4860].
3. Elements of Procedures
This section describes the procedures used to implement the aggregate
RSVP procedure over PCN. It is considered that the procedures for
aggregation of E2E reservations over generic aggregate RSVP
reservations are the same as the procedures specified in Section 4 of
[RFC4860], except where a departure from these procedures is
explicitly described in this section. Please refer to Appendix B of
[RFC2205] and Section 3 of [RFC4860] for the processing rules and
error handling for the error cases listed below:
o Message formatting errors, e.g., incomplete message
o Unknown objects
3.1. Receipt of E2E Path Message by PCN-Ingress-Node
(Aggregating Router)
When the E2E Path message arrives at the exterior interface of the
Aggregator (PCN-ingress-node), then standard RSVP generic aggregation
[RFC4860] procedures are used.
3.2. Handling of E2E Path Message by Interior Routers
The E2E Path messages traverse zero or more PCN-interior-nodes. The
PCN-interior-nodes receive the E2E Path message on an interior
interface and forward it on another interior interface. It is
considered that, by configuration, the PCN-interior-nodes ignore the
E2E RSVP signaling messages [RFC2205]. Therefore, the E2E Path
messages are simply forwarded as normal IP datagrams.
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3.3. Receipt of E2E Path Message by PCN-Egress-Node
(Deaggregating Router)
When receiving the E2E Path message, the Deaggregator (PCN-egress-
node and Decision Point) performs the regular procedures of
[RFC4860], augmented with the following rules:
o The Deaggregator MUST NOT perform the RSVP-TTL vs. IP TTL-check
(TTL = Time To Live) and MUST NOT update the ADSPEC Break bit.
This is because the whole PCN-domain is effectively handled by E2E
RSVP as a virtual link on which integrated service is indeed
supported (and admission control performed) so that the Break bit
MUST NOT be set; see also [RSVP-PCN-CL].
The Deaggregator forwards the E2E Path message towards the receiver.
3.4. Initiation of New Aggregate Path Message by PCN-Ingress-Node
(Aggregating Router)
To comply with this specification, for the initiation of the new RSVP
generic aggregate Path message by the Aggregator (PCN-ingress-node),
the same methods MUST be used as the ones described in [RFC4860].
3.5. Handling of Aggregate Path Message by Interior Routers
The Aggregate Path messages traverse zero or more PCN-interior-nodes.
The PCN-interior-nodes receive the Aggregate Path message on an
interior interface and forward it on another interior interface. It
is considered that, by configuration, the PCN-interior-nodes ignore
the Aggregate Path signaling messages. Therefore, the Aggregate Path
messages are simply forwarded as normal IP datagrams.
3.6. Handling of Aggregate Path Message by Deaggregating Router
When receiving the Aggregate Path message, the Deaggregator
(PCN-egress-node and Decision Point) performs the regular procedures
of [RFC4860], augmented with the following rules:
o When the received Aggregate Path message by the Deaggregator
contains the RSVP-AGGREGATE-IPv4-PCN-response or RSVP-AGGREGATE-
IPv6-PCN-response PCN objects, which carry the PCN-sent-rate, then
the procedures specified in Section 3.18 of this document MUST be
followed.
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3.7. Handling of E2E Resv Message by Deaggregating Router
When the E2E Resv message arrives at the exterior interface of the
Deaggregator (PCN-egress-node and Decision Point), then standard RSVP
aggregation procedures of [RFC4860] are used, augmented with the
following rules:
o The E2E RSVP SESSION associated with an E2E Resv message that
arrives at the external interface of the Deaggregator is
mapped/matched with an RSVP generic aggregate and with a PCN
ingress-egress-aggregate.
o Depending on the type of the PCN edge behavior supported by the
Deaggregator, the PCN admission control procedures specified in
Section 3.3.1 of [RFC6661] or [RFC6662] MUST be followed. Since
no admission control procedures over the RSVP aggregate
reservations in the PCN-core are required, unlike [RFC4860], the
Deaggregator does not perform any admission control of the E2E
reservation over the mapped generic aggregate RSVP reservation.
If the PCN-based admission control procedure is successful, then
the Deaggregator MUST allow the new flow to be admitted onto the
associated RSVP generic aggregation reservation and onto the PCN
ingress-egress-aggregate; see [RFC6661] and [RFC6662]. If the
PCN-based admission control procedure is not successful, then the
E2E Resv MUST NOT be admitted onto the associated RSVP generic
aggregate reservation and onto the PCN ingress-egress-aggregation.
The E2E Resv message is further processed according to [RFC4860].
How the PCN-admission-state is maintained is specified in [RFC6661]
and [RFC6662].
3.8. Handling of E2E Resv Message by Interior Routers
The E2E Resv messages traversing the PCN-core are IP addressed to the
Aggregating router and are not marked with Router Alert; therefore,
the E2E Resv messages are simply forwarded as normal IP datagrams.
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3.9. Initiation of New Aggregate Resv Message by Deaggregating Router
To comply with this specification, for the initiation of the new RSVP
generic aggregate Resv message by the Deaggregator (PCN-egress-node
and Decision Point), the same methods MUST be used as the ones
described in Section 4 of [RFC4860], augmented with the following
rules:
o The size of the generic aggregate reservation is irrelevant (see
Section 2.6) and can be set to any arbitrary value by the
PCN-egress-node. The Deaggregator SHOULD set the value of an RSVP
generic aggregate reservation to a null bandwidth. We also
observe that there is no need for dynamic adjustment of the RSVP
generic aggregate reservation size.
o When [RFC6661] is used and the ETM-rate measured by the
Deaggregator contains a non-zero value for some ingress-egress-
aggregate (see [RFC6661] and [RFC6662]), the Deaggregator MUST
request the PCN-ingress-node to provide an estimate of the rate
(PCN-sent-rate) at which the Aggregator (PCN-ingress-node) is
receiving PCN-traffic that is destined for the given ingress-
egress-aggregate.
o When [RFC6662] is used and the PCN-admission-state computed by the
Deaggregator on the basis of the CLE is "block" for the given
ingress-egress-aggregate, the Deaggregator MUST request the
PCN-ingress-node to provide an estimate of the rate
(PCN-sent-rate) at which the Aggregator is receiving PCN-traffic
that is destined for the given ingress-egress-aggregate.
o In the above two cases and when the PCN-sent-rate needs to be
requested from the Aggregator, the Deaggregator MUST generate and
send to the Aggregator a (refresh) Aggregate Resv message that
MUST carry one of the following PCN objects (see Section 4.1),
depending on whether IPv4 or IPv6 is supported:
o RSVP-AGGREGATE-IPv4-PCN-request
o RSVP-AGGREGATE-IPv6-PCN-request
3.10. Handling of Aggregate Resv Message by Interior Routers
The Aggregate Resv messages traversing the PCN-core are IP addressed
to the Aggregating router and are not marked with Router Alert;
therefore, the Aggregate Resv messages are simply forwarded as normal
IP datagrams.
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3.11. Handling of E2E Resv Message by Aggregating Router
When the E2E Resv message arrives at the interior interface of the
Aggregator (PCN-ingress-node), then standard RSVP aggregation
procedures of [RFC4860] are used.
3.12. Handling of Aggregate Resv Message by Aggregating Router
When the Aggregate Resv message arrives at the interior interface of
the Aggregator (PCN-ingress-node), then standard RSVP aggregation
procedures of [RFC4860] are used, augmented with the following rules:
o The Aggregator SHOULD use the information carried by the PCN
objects (see Section 4) and follow the steps specified in
Section 3.4 of [RFC6661] and [RFC6662]. If the "R" flag carried
by the RSVP-AGGREGATE-IPv4-PCN-request or RSVP-AGGREGATE-IPv6-PCN-
request PCN objects is set to ON (see Section 4.1), then the
Aggregator follows the steps described in Section 3.4 of [RFC6661]
and [RFC6662] on calculating the PCN-sent-rate. In particular,
the Aggregator MUST provide the estimated current rate of
PCN-traffic received at that node and destined for a given
ingress-egress-aggregate in octets per second (the PCN-sent-rate).
The way this rate estimate is derived is a matter of
implementation; see [RFC6661] or [RFC6662].
o The Aggregator initiates an Aggregate Path message. In
particular, when the Aggregator receives an Aggregate Resv message
that carries one of the following PCN objects -- RSVP-AGGREGATE-
IPv4-PCN-request or RSVP-AGGREGATE-IPv6-PCN-request -- with the
"R" flag set to ON (see Section 4.1), the Aggregator initiates an
Aggregate Path message and includes the calculated PCN-sent-rate
in the RSVP-AGGREGATE-IPv4-PCN-response or RSVP-AGGREGATE-
IPv6-PCN-response PCN objects (see Section 4.1), which MUST be
carried by the Aggregate Path message. This Aggregate Path
message is sent towards the Deaggregator (PCN-egress-node and
Decision Point) that requested the calculation of the
PCN-sent-rate.
3.13. Removal of E2E Reservation
To comply with this specification, for the removal of E2E
reservations, the same methods MUST be used as the ones described in
Section 4 of [RFC4860] and Section 5 of [RFC4495].
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3.14. Removal of Aggregate Reservation
To comply with this specification, for the removal of RSVP generic
aggregate reservations, the same methods MUST be used as the ones
described in Section 4 of [RFC4860] and Section 2.10 of [RFC3175].
In particular, should an aggregate reservation go away (presumably
due to a configuration change, route change, or policy event), the
E2E reservations it supports are no longer active. They MUST be
treated accordingly.
3.15. Handling of Data on Reserved E2E Flow by Aggregating Router
The handling of data on the reserved E2E flow by the Aggregator
(PCN-ingress-node) uses the procedures described in [RFC4860],
augmented with the following:
o Regarding PCN-marking and traffic classification, the procedures
defined in Sections 2.2 and 2.3 of this document are used.
3.16. Procedures for Multicast Sessions
No multicast sessions are considered in this document.
3.17. Misconfiguration of PCN-Node
In an event where a PCN-node is misconfigured within a PCN-domain,
the desired behavior is the same as that described in Section 3.10.
3.18. PCN-Based Flow Termination
When the Deaggregator (PCN-egress-node and Decision Point) needs to
terminate an amount of traffic associated with one ingress-egress-
aggregate (see Section 3.3.2 of [RFC6661] and [RFC6662]), then
several procedures for terminating E2E microflows can be deployed.
The default procedure for terminating E2E microflows (i.e.,
PCN-flows) is as follows; see, for example, [RFC6661] and [RFC6662].
For the same ingress-egress-aggregate, select a number of E2E
microflows to be terminated in order to decrease the total incoming
amount of bandwidth associated with one ingress-egress-aggregate by
the amount of traffic to be terminated. In this situation, the same
mechanisms for terminating an E2E microflow can be followed as the
mechanisms specified in [RFC2205]. However, based on a local policy,
the Deaggregator could use other ways of selecting which microflows
should be terminated. For example, for the same ingress-egress-
aggregate, select a number of E2E microflows to be terminated or to
reduce their reserved bandwidth in order to decrease the total
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incoming amount of bandwidth associated with one ingress-egress-
aggregate by the amount of traffic to be terminated. In this
situation, the same mechanisms for terminating an E2E microflow or
reducing bandwidth associated with an E2E microflow can be followed
as the mechanisms specified in Section 5 of [RFC4495].
4. Protocol Elements
The protocol elements in this document are using the elements defined
in Section 4 of [RFC4860] and Section 3 of [RFC3175], augmented with
the following rules:
o The DSCP value included in the SESSION object SHOULD be set equal
to a PCN-compatible Diffserv Codepoint.
o The Extended vDstPort SHOULD be set to the IPv4 or IPv6
destination addresses of the Aggregator (PCN-ingress-node); see
[RFC4860].
o When the Deaggregator (PCN-egress-node and Decision Point) needs
to request the PCN-sent-rate from the PCN-ingress-node (see
Section 3.9 of this document), the Deaggregator MUST generate and
send a (refresh) Aggregate Resv message to the Aggregator that
MUST carry one of the following PCN objects (see Section 4.1),
depending on whether IPv4 or IPv6 is supported:
o RSVP-AGGREGATE-IPv4-PCN-request
o RSVP-AGGREGATE-IPv6-PCN-request
o When the Aggregator receives an Aggregate Resv message that
carries one of the following PCN objects -- RSVP-AGGREGATE-
IPv4-PCN-request or RSVP-AGGREGATE-IPv6-PCN-request, with the "R"
flag set to ON (see Section 4.1) -- then the Aggregator MUST
generate and send to the Deaggregator an Aggregate Path message
that carries one of the following PCN objects (see Section 4.1),
depending on whether IPv4 or IPv6 is supported:
o RSVP-AGGREGATE-IPv4-PCN-response
o RSVP-AGGREGATE-IPv6-PCN-response
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4.1. PCN Objects
This section describes four types of PCN objects that can be carried
by the (refresh) Aggregate Path or the (refresh) Aggregate Resv
messages specified in [RFC4860].
These objects are as follows:
o RSVP-AGGREGATE-IPv4-PCN-request
o RSVP-AGGREGATE-IPv6-PCN-request
o RSVP-AGGREGATE-IPv4-PCN-response
o RSVP-AGGREGATE-IPv6-PCN-response
o RSVP-AGGREGATE-IPv4-PCN-request: PCN request object, when IPv4
addresses are used:
Class = 248 (PCN)
C-Type = 1 (RSVP-AGGREGATE-IPv4-PCN-request)
+-------------+-------------+-------------+-------------+
| IPv4 PCN-ingress-node Address (4 bytes) |
+-------------+-------------+-------------+-------------+
| IPv4 PCN-egress-node Address (4 bytes) |
+-------------+-------------+-------------+-------------+
| IPv4 Decision Point Address (4 bytes) |
+-------------+-------------+-------------+-------------+
|R| Reserved |
+-------------+-------------+-------------+-------------+
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o RSVP-AGGREGATE-IPv6-PCN-request: PCN object, when IPv6 addresses
are used:
Class = 248 (PCN)
C-Type = 2 (RSVP-AGGREGATE-IPv6-PCN-request)
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ IPv6 PCN-ingress-node Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ IPv6 PCN-egress-node Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ Decision Point Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
|R| Reserved |
+-------------+-------------+-------------+-------------+
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o RSVP-AGGREGATE-IPv4-PCN-response: PCN object, IPv4 addresses
are used:
Class = 248 (PCN)
C-Type = 3 (RSVP-AGGREGATE-IPv4-PCN-response)
+-------------+-------------+-------------+-------------+
| IPv4 PCN-ingress-node Address (4 bytes) |
+-------------+-------------+-------------+-------------+
| IPv4 PCN-egress-node Address (4 bytes) |
+-------------+-------------+-------------+-------------+
| IPv4 Decision Point Address (4 bytes) |
+-------------+-------------+-------------+-------------+
| PCN-sent-rate |
+-------------+-------------+-------------+-------------+
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o RSVP-AGGREGATE-IPv6-PCN-response: PCN object, IPv6 addresses
are used:
Class = 248 (PCN)
C-Type = 4 (RSVP-AGGREGATE-IPv6-PCN-response)
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ IPv6 PCN-ingress-node Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ IPv6 PCN-egress-node Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ Decision Point Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
| PCN-sent-rate |
+-------------+-------------+-------------+-------------+
The fields carried by the PCN object are specified in [RFC6663],
[RFC6661], and [RFC6662]:
o The IPv4 or IPv6 address of the PCN-ingress-node (Aggregator) and
the IPv4 or IPv6 address of the PCN-egress-node (Deaggregator):
together, they specify the ingress-egress-aggregate to which the
report refers. According to [RFC6663], the report should carry
the identifier of the PCN-ingress-node (Aggregator) and the
identifier of the PCN-egress-node (Deaggregator) (typically their
IP addresses).
o Decision Point Address: specifies the IPv4 or IPv6 address of the
Decision Point. In this document, this field MUST contain the IP
address of the Deaggregator.
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o "R": 1-bit flag that, when set to ON, signifies, according to
[RFC6661] and [RFC6662], that the PCN-ingress-node (Aggregator)
MUST provide an estimate of the rate (PCN-sent-rate) at which the
PCN-ingress-node (Aggregator) is receiving PCN-traffic that is
destined for the given ingress-egress-aggregate.
o "Reserved": 31 bits that are currently not used by this document
and are reserved. These SHALL be set to 0 and SHALL be ignored on
reception.
o PCN-sent-rate: the estimate of the rate at which the PCN-ingress-
node (Aggregator) is receiving PCN-traffic that is destined for
the given ingress-egress-aggregate. It is expressed in
octets/second; its format is a 32-bit IEEE floating-point number.
The PCN-sent-rate is specified in [RFC6661] and [RFC6662].
5. Security Considerations
The security considerations specified in [RFC2205], [RFC4860], and
[RFC5559] apply to this document. In addition, [RFC4230] and
[RFC6411] provide useful guidance on RSVP security mechanisms.
Security within a PCN-domain is fundamentally based on the controlled
environment trust assumption stated in Section 6.3.1 of [RFC5559] --
in particular, that all PCN-nodes are PCN-enabled and are trusted to
perform accurate PCN-metering and PCN-marking.
In the PCN-domain environments addressed by this document, Generic
Aggregate RSVP messages specified in [RFC4860] are used for support
of the PCN Controlled Load (CL) and Single Marking (SM) edge
behaviors over a Diffserv cloud using Pre-Congestion Notification.
Hence, the security mechanisms discussed in [RFC4860] are applicable.
Specifically, the INTEGRITY object [RFC2747] [RFC3097] can be used to
provide hop-by-hop RSVP message integrity, node authentication, and
replay protection, thereby protecting against corruption and spoofing
of RSVP messages and PCN feedback conveyed by RSVP messages.
For these reasons, this document does not introduce significant
additional security considerations beyond those discussed in
[RFC5559] and [RFC4860].
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6. IANA Considerations
IANA has modified the "Class Names, Class Numbers, and Class Types"
subregistry of the "Resource Reservation Protocol (RSVP) Parameters"
registry, to add a new Class Number and assign four new C-Types under
this new Class Number, as described below; see Section 4.1:
Class
Number Class Name Reference
------- ---------------------- -------------
248 PCN RFC 7417
Class Types or C-Types - 248 PCN
Value Description Reference
------ ------------------------------ ------------
1 RSVP-AGGREGATE-IPv4-PCN-request RFC 7417
2 RSVP-AGGREGATE-IPv6-PCN-request RFC 7417
3 RSVP-AGGREGATE-IPv4-PCN-response RFC 7417
4 RSVP-AGGREGATE-IPv6-PCN-response RFC 7417
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, September 1997,
<http://www.rfc-editor.org/info/rfc2205>.
[RFC3140] Black, D., Brim, S., Carpenter, B., and F. Le Faucheur,
"Per Hop Behavior Identification Codes", RFC 3140,
June 2001, <http://www.rfc-editor.org/info/rfc3140>.
[RFC3175] Baker, F., Iturralde, C., Le Faucheur, F., and B. Davie,
"Aggregation of RSVP for IPv4 and IPv6 Reservations",
RFC 3175, September 2001,
<http://www.rfc-editor.org/info/rfc3175>.
[RFC4495] Polk, J. and S. Dhesikan, "A Resource Reservation Protocol
(RSVP) Extension for the Reduction of Bandwidth of a
Reservation Flow", RFC 4495, May 2006,
<http://www.rfc-editor.org/info/rfc4495>.
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[RFC4860] Le Faucheur, F., Davie, B., Bose, P., Christou, C., and M.
Davenport, "Generic Aggregate Resource ReSerVation
Protocol (RSVP) Reservations", RFC 4860, May 2007,
<http://www.rfc-editor.org/info/rfc4860>.
[RFC5670] Eardley, P., Ed., "Metering and Marking Behaviour of
PCN-Nodes", RFC 5670, November 2009,
<http://www.rfc-editor.org/info/rfc5670>.
[RFC6660] Briscoe, B., Moncaster, T., and M. Menth, "Encoding Three
Pre-Congestion Notification (PCN) States in the IP Header
Using a Single Diffserv Codepoint (DSCP)", RFC 6660,
July 2012, <http://www.rfc-editor.org/info/rfc6660>.
[RFC6661] Charny, A., Huang, F., Karagiannis, G., Menth, M., and T.
Taylor, Ed., "Pre-Congestion Notification (PCN) Boundary-
Node Behavior for the Controlled Load (CL) Mode of
Operation", RFC 6661, July 2012,
<http://www.rfc-editor.org/info/rfc6661>.
[RFC6662] Charny, A., Zhang, J., Karagiannis, G., Menth, M., and T.
Taylor, Ed., "Pre-Congestion Notification (PCN) Boundary-
Node Behavior for the Single Marking (SM) Mode of
Operation", RFC 6662, July 2012,
<http://www.rfc-editor.org/info/rfc6662>.
[RFC6663] Karagiannis, G., Taylor, T., Chan, K., Menth, M., and P.
Eardley, "Requirements for Signaling of Pre-Congestion
Information in a Diffserv Domain", RFC 6663, July 2012,
<http://www.rfc-editor.org/info/rfc6663>.
7.2. Informative References
[RFC1633] Braden, R., Clark, D., and S. Shenker, "Integrated
Services in the Internet Architecture: an Overview",
RFC 1633, June 1994,
<http://www.rfc-editor.org/info/rfc1633>.
[RFC2211] Wroclawski, J., "Specification of the Controlled-Load
Network Element Service", RFC 2211, September 1997,
<http://www.rfc-editor.org/info/rfc2211>.
[RFC2212] Shenker, S., Partridge, C., and R. Guerin, "Specification
of Guaranteed Quality of Service", RFC 2212,
September 1997, <http://www.rfc-editor.org/info/rfc2212>.
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RFC 7417 Aggregate RSVP over PCN December 2014
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474,
December 1998, <http://www.rfc-editor.org/info/rfc2474>.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
and W. Weiss, "An Architecture for Differentiated
Services", RFC 2475, December 1998,
<http://www.rfc-editor.org/info/rfc2475>.
[RFC2747] Baker, F., Lindell, B., and M. Talwar, "RSVP Cryptographic
Authentication", RFC 2747, January 2000,
<http://www.rfc-editor.org/info/rfc2747>.
[RFC2753] Yavatkar, R., Pendarakis, D., and R. Guerin, "A Framework
for Policy-based Admission Control", RFC 2753,
January 2000, <http://www.rfc-editor.org/info/rfc2753>.
[RFC2998] Bernet, Y., Ford, P., Yavatkar, R., Baker, F., Zhang, L.,
Speer, M., Braden, R., Davie, B., Wroclawski, J., and E.
Felstaine, "A Framework for Integrated Services Operation
over Diffserv Networks", RFC 2998, November 2000,
<http://www.rfc-editor.org/info/rfc2998>.
[RFC3097] Braden, R. and L. Zhang, "RSVP Cryptographic
Authentication -- Updated Message Type Value", RFC 3097,
April 2001, <http://www.rfc-editor.org/info/rfc3097>.
[RFC4230] Tschofenig, H. and R. Graveman, "RSVP Security
Properties", RFC 4230, December 2005,
<http://www.rfc-editor.org/info/rfc4230>.
[RFC4923] Baker, F. and P. Bose, "Quality of Service (QoS) Signaling
in a Nested Virtual Private Network", RFC 4923,
August 2007, <http://www.rfc-editor.org/info/rfc4923>.
[RFC5559] Eardley, P., Ed., "Pre-Congestion Notification (PCN)
Architecture", RFC 5559, June 2009,
<http://www.rfc-editor.org/info/rfc5559>.
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[RFC6411] Behringer, M., Le Faucheur, F., and B. Weis,
"Applicability of Keying Methods for RSVP Security",
RFC 6411, October 2011,
<http://www.rfc-editor.org/info/rfc6411>.
[RSVP-PCN-CL]
Le Faucheur, F., Charny, A., Briscoe, B., Eardley, P.,
Babiarz, J., and K. Chan, "RSVP Extensions for Admission
Control over Diffserv using Pre-congestion Notification
(PCN)", Work in Progress, draft-lefaucheur-rsvp-ecn-01,
June 2006.
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Appendix A. Example Signaling Flow
This appendix is based on Appendix A of [RFC4860]. In particular, it
provides an example signaling flow of the specifications detailed in
Sections 3 and 4.
This signaling flow assumes an environment where E2E reservations are
aggregated over generic aggregate RSVP reservations and applied over
a PCN-domain. In particular, the Aggregator (PCN-ingress-node) and
Deaggregator (PCN-egress-node) are located at the boundaries of the
PCN-domain. The PCN-interior-nodes are located within the
PCN-domain, between the PCN-boundary-nodes, but are not shown in the
diagram below. It illustrates a possible RSVP message flow that
could take place in the successful establishment of a unicast E2E
reservation that is the first between a given Aggregator-Deaggregator
pair.
Aggregator (PCN-ingress-node) Deaggregator (PCN-egress-node)
E2E Path
----------->
(1)
E2E Path
------------------------------->
(2)
E2E PathErr(NEW-AGGREGATE-NEEDED,SOI=GApcn)
<----------------------------------------
(3)
AggPath(Session=GApcn)
------------------------------->
(4)
E2E Path
----------->
(5)
AggResv (Session=GApcn) (PCN object)
<-------------------------------
(6)
AggResvConfirm (Session=GApcn)
------------------------------>
(7)
E2E Resv
<---------
(8)
E2E Resv (SOI=GApcn)
<-----------------------------
(9)
E2E Resv
<-----------
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(1) The Aggregator forwards E2E Path into the aggregation region
after modifying its IP protocol number to RSVP-E2E-IGNORE.
(2) Let's assume that no Aggregate Path exists. To be able to
accurately update the ADSPEC of the E2E Path, the Deaggregator
needs the ADSPEC of Aggregate Path. In this example, the
Deaggregator elects to instruct the Aggregator to set up an
Aggregate Path state for the PCN PHB-ID. To do that, the
Deaggregator sends an E2E PathErr message with a
NEW-AGGREGATE-NEEDED PathErr code.
The PathErr message also contains a SESSION-OF-INTEREST (SOI)
object. The SOI contains a GENERIC-AGGREGATE SESSION (GApcn)
whose PHB-ID is set to the PCN PHB-ID. The GENERIC-AGGREGATE
SESSION contains an interface-independent Deaggregator address
inside the DestAddress and appropriate values inside the vDstPort
and Extended vDstPort fields. In this document, the Extended
vDstPort SHOULD contain the IPv4 or IPv6 address of the
Aggregator.
(3) The Aggregator follows the request from the Deaggregator and
signals an Aggregate Path for the GENERIC-AGGREGATE SESSION
(GApcn).
(4) The Deaggregator takes into account the information contained in
the ADSPEC from both Aggregate Paths and updates the E2E Path
ADSPEC accordingly. The PCN-egress-node MUST NOT perform the
RSVP-TTL vs. IP TTL-check and MUST NOT update the ADSPEC Break
bit. This is because the whole PCN-domain is effectively handled
by E2E RSVP as a virtual link on which integrated service is
indeed supported (and admission control performed) so that the
Break bit MUST NOT be set; see also [RSVP-PCN-CL]. The
Deaggregator also modifies the E2E Path IP protocol number to
RSVP before forwarding it.
(5) In this example, the Deaggregator elects to immediately proceed
with establishment of the generic aggregate reservation. In
effect, the Deaggregator can be seen as anticipating the actual
demand of E2E reservations so that the generic aggregate
reservation is in place when the E2E Resv request arrives, in
order to speed up establishment of E2E reservations. Here it is
also assumed that the Deaggregator includes the optional
ResvConfirm Request in the Aggregate Resv message.
(6) The Aggregator merely complies with the received ResvConfirm
Request and returns the corresponding Aggregate ResvConfirm.
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(7) The Deaggregator has explicit confirmation that the generic
aggregate reservation is established.
(8) On receipt of the E2E Resv, the Deaggregator applies the mapping
policy defined by the network administrator to map the E2E Resv
onto a generic aggregate reservation. Let's assume that this
policy is such that the E2E reservation is to be mapped onto the
generic aggregate reservation with the PCN PHB-ID=x. After the
previous step (7), the Deaggregator knows that a generic
aggregate reservation (GApcn) is in place for the corresponding
PHB-ID. At this step, the Deaggregator maps the generic
aggregate reservation onto one ingress-egress-aggregate
maintained by the Deaggregator (as a PCN-egress-node); see
Section 3.7. The Deaggregator performs admission control of the
E2E Resv onto the generic aggregate reservation for the PCN
PHB-ID (GApcn). The Deaggregator also takes into account the PCN
admission control procedure as specified in [RFC6661] and
[RFC6662]; see Section 3.7. If one or both of the admission
control procedures (the PCN-based admission control procedure
described in Section 3.3.1 of [RFC6661] or [RFC6662], and the
admission control procedure specified in [RFC4860]) are not
successful, then the E2E Resv is not admitted onto the associated
RSVP generic aggregate reservation for the PCN PHB-ID (GApcn).
Otherwise, assuming that the generic aggregate reservation for
the PCN (GApcn) had been established with sufficient bandwidth to
support the E2E Resv, the Deaggregator adjusts its counter,
tracking the unused bandwidth on the generic aggregate
reservation. Then it forwards the E2E Resv to the Aggregator,
including a SESSION-OF-INTEREST object conveying the selected
mapping onto GApcn (and hence onto the PCN PHB-ID).
(9) The Aggregator records the mapping of the E2E Resv onto GApcn
(and onto the PCN PHB-ID). The Aggregator removes the SOI object
and forwards the E2E Resv towards the sender.
Acknowledgments
We would like to thank the authors of [RSVP-PCN-CL], since some ideas
used in this document are based on the work initiated in
[RSVP-PCN-CL]. Moreover, we would like to thank Bob Briscoe, David
Black, Ken Carlberg, Tom Taylor, Philip Eardley, Michael Menth, Toby
Moncaster, James Polk, Scott Bradner, Lixia Zhang, and Robert Sparks
for the provided comments. In particular, we would like to thank
Francois Le Faucheur for contributing a significant amount of text,
in addition to his comments.
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Authors' Addresses
Georgios Karagiannis
Huawei Technologies
Hansaallee 205
40549 Dusseldorf
Germany
EMail: Georgios.Karagiannis@huawei.com
Anurag Bhargava
Cisco Systems, Inc.
7100-9 Kit Creek Road
PO Box 14987
Research Triangle Park, NC 27709-4987
United States
EMail: anuragb@cisco.com
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