draft-ietf-tsvwg-rsvp-dste-00.txt   draft-ietf-tsvwg-rsvp-dste-01.txt 
RSVP Aggregation over MPLS TE tunnels July 2005 RSVP Aggregation over MPLS TE tunnels February 2006
Internet Draft Francois Le Faucheur Internet Draft Francois Le Faucheur
Michael Dibiasio Michael DiBiasio
Bruce Davie Bruce Davie
Cisco Systems, Inc. Cisco Systems, Inc.
Michael Davenport Michael Davenport
Chris Christou Chris Christou
Booz Allen Hamilton Booz Allen Hamilton
Jerry Ash Jerry Ash
Bur Goode Bur Goode
AT&T AT&T
draft-ietf-tsvwg-rsvp-dste-00.txt draft-ietf-tsvwg-rsvp-dste-01.txt
Expires: January 2006 July 2005 Expires: August 2006 February 2006
Aggregation of RSVP Reservations over MPLS TE/DS-TE Tunnels Aggregation of RSVP Reservations over MPLS TE/DS-TE Tunnels
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
skipping to change at page 2, line 5 skipping to change at page 1, line 46
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
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Abstract Abstract
RSVP Aggregation over MPLS TE tunnels July 2005 RFC 3175 specifies aggregation of RSVP end-to-end reservations over
aggregate RSVP reservations. This document specifies aggregation of
RSVP end-to-end reservations over MPLS Traffic Engineering (TE)
This document provides specification for aggregation of RSVP end-to- RSVP Aggregation over MPLS TE tunnels February 2006
end reservations over MPLS Traffic Engineering (TE) tunnels or MPLS
Diffserv-aware MPLS Traffic Engineering (DS-TE) Tunnels. This tunnels or MPLS Diffserv-aware MPLS Traffic Engineering (DS-TE)
approach is based on RFC 3175 and simply modifies the corresponding Tunnels. This approach is based on RFC 3175 and simply modifies the
procedures for operations over MPLS TE tunnels instead of aggregated corresponding procedures for operations over MPLS TE tunnels instead
RSVP reservations. This approach can be used to achieve admission of aggregate RSVP reservations. This approach can be used to achieve
control of a very large number of flows in a scalable manner since admission control of a very large number of flows in a scalable
the devices in the core of the network are unaware of the end-to-end manner since the devices in the core of the network are unaware of
RSVP reservations and are only aware of the MPLS TE tunnels. the end-to-end RSVP reservations and are only aware of the MPLS TE
tunnels.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society. (2005) Copyright (C) The Internet Society (2006).
Specification of Requirements Specification of Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
1. Introduction 1. Introduction
The Integrated Services (Intserv) [INT-SERV] architecture provides a The Integrated Services (Intserv) [INT-SERV] architecture provides a
skipping to change at page 2, line 45 skipping to change at page 2, line 44
Certain applications that have quantifiable resource requirements Certain applications that have quantifiable resource requirements
express these requirements using Intserv parameters as defined in the express these requirements using Intserv parameters as defined in the
appropriate Intserv service specifications ([GUARANTEED], appropriate Intserv service specifications ([GUARANTEED],
[CONTROLLED]). [CONTROLLED]).
The Differentiated Services (DiffServ) architecture ([DIFFSERV]) was The Differentiated Services (DiffServ) architecture ([DIFFSERV]) was
then developed to support differentiated treatment of packets in very then developed to support differentiated treatment of packets in very
large scale environments. In contrast to the per-flow orientation of large scale environments. In contrast to the per-flow orientation of
Intserv and RSVP, Diffserv networks classify packets into one of a Intserv and RSVP, Diffserv networks classify packets into one of a
small number of aggregated flows or "classes", based on the Diffserv small number of aggregated flows or "classes", based on the Diffserv
codepoint (DSCP) in the packet's IP header. At each Diffserv router, codepoint (DSCP) in the packet IP header. At each Diffserv router,
packets are subjected to a "per-hop behavior" (PHB), which is invoked packets are subjected to a "per-hop behavior" (PHB), which is invoked
by the DSCP. The primary benefit of Diffserv is its scalability. by the DSCP. The primary benefit of Diffserv is its scalability.
Diffserv eliminates the need for per-flow state and per-flow Diffserv eliminates the need for per-flow state and per-flow
processing and therefore scales well to large networks. processing and therefore scales well to large networks.
However, DiffServ does not include any mechanism for communication However, DiffServ does not include any mechanism for communication
between applications and the network. Thus, as detailed in [INT-DIFF], between applications and the network. Thus, as detailed in [INT-DIFF],
significant benefits can be achieved by using Intserv over Diffserv significant benefits can be achieved by using Intserv over Diffserv
including resource based admission control, policy based admission
RSVP Aggregation over MPLS TE tunnels July 2005 RSVP Aggregation over MPLS TE tunnels February 2006
including resource based admission control, policy based admission
control, assistance in traffic identification /classification and control, assistance in traffic identification /classification and
traffic conditioning. As discussed in [INT-DIFF], Intserv can operate traffic conditioning. As discussed in [INT-DIFF], Intserv can operate
over Diffserv in multiple ways. For example, the Diffserv region may over Diffserv in multiple ways. For example, the Diffserv region may
be statically provisioned or may be RSVP aware. When it is RSVP aware, be statically provisioned or may be RSVP aware. When it is RSVP aware,
several mechanisms may be used to support dynamic provisioning and several mechanisms may be used to support dynamic provisioning and
topology aware admission control including aggregated RSVP topology aware admission control including aggregate RSVP
reservations, per flow RSVP or a bandwidth broker. The advantage of reservations, per flow RSVP or a bandwidth broker. The advantage of
using aggregated RSVP reservations is that it offers dynamic, using aggregate RSVP reservations is that it offers dynamic,
topology-aware admission control over the Diffserv region without the topology-aware admission control over the Diffserv region without
scalability burden of per-flow reservations and the associated level per-flow reservations and the associated level of RSVP signaling in
of RSVP signaling in the Diffserv core. [RSVP-AGGR] describes in the Diffserv core. In turn, this allows dynamic, topology aware
detail how to perform such aggregation of end to end RSVP admission control of flows requiring QoS reservations over the
reservations over aggregated RSVP reservations in a Diffserv cloud. Diffserv core even when the total number of such flows carried over
It establishes an architecture where multiple end-to-end RSVP the Diffserv core is extremely large.
reservations sharing the same ingress router (Aggregator) and the
same egress router (Deaggregator) at the edges of an "aggregation
region", can be mapped onto a single aggregate reservation within the
aggregation region. This considerably reduces the amount of
reservation state that needs to be maintained by routers within the
aggregation region. Furthermore, traffic belonging to aggregate
reservations is classified in the data path purely using Diffserv
marking.
[MPLS-TE] describes how MPLS TE Tunnels can be established via [RSVP- [RSVP-AGG] describes in detail how to perform such aggregation of end
TE] and how these tunnels can be used to carry arbitrary aggregates to end RSVP reservations over aggregate RSVP reservations in a
of traffic. MPLS TE uses Constraint Based Routing to compute the path Diffserv cloud. It establishes an architecture where multiple end-to-
for a TE tunnel. Then, CAC (Call Admission Control) is performed end RSVP reservations sharing the same ingress router (Aggregator)
during the establishment of TE Tunnels to ensure they are granted and the same egress router (Deaggregator) at the edges of an
their requested resources. "aggregation region", can be mapped onto a single aggregate
reservation within the aggregation region. This considerably reduces
the amount of reservation state that needs to be maintained by
routers within the aggregation region. Furthermore, traffic belonging
to aggregate reservations is classified in the data path purely using
Diffserv marking.
[MPLS-TE] describes how MPLS Traffic Engineering (TE) Tunnels can be
used to carry arbitrary aggregates of traffic for the purposes of
traffic engineering. [RSVP-TE] specifies how such MPLS TE Tunnels can
be established using RSVP-TE signaling. . MPLS TE uses Constraint
Based Routing to compute the path for a TE tunnel. Then, Admission
Control is performed during the establishment of TE Tunnels to ensure
they are granted their requested resources.
[DSTE-REQ] presents the Service Providers requirements for support of [DSTE-REQ] presents the Service Providers requirements for support of
Diff-Serv-aware MPLS Traffic Engineering (DS-TE). With DS-TE, Diff-Serv-aware MPLS Traffic Engineering (DS-TE). With DS-TE,
separate DS-TE tunnels can be used to carry different Diffserv separate DS-TE tunnels can be used to carry different Diffserv
classes of traffic and different resource constraints can be enforced classes of traffic and different resource constraints can be enforced
for these different classes. [DSTE-PROTO] specifies RSVP-TE signaling for these different classes. [DSTE-PROTO] specifies RSVP-TE signaling
extensions as well as OSPF and ISIS extensions for support of DS-TE. extensions as well as OSPF and ISIS extensions for support of DS-TE.
In the rest of this document we will refer to both TE tunnels and DS- In the rest of this document we will refer to both TE tunnels and DS-
TE tunnels simply as "TE tunnels". TE tunnels simply as "TE tunnels".
TE tunnels have much in common with the aggregate RSVP reservations TE tunnels have much in common with the aggregate RSVP reservations
used in [RSVP-AGGR]: used in [RSVP-AGG]:
- a TE tunnel is subject to CAC and thus is effectively an - a TE tunnel is subject to Admission Control and thus is
aggregate bandwidth reservation effectively an aggregate bandwidth reservation
RSVP Aggregation over MPLS TE tunnels February 2006
- In the data plane, packet scheduling relies exclusively on - In the data plane, packet scheduling relies exclusively on
Diff-Serv classification and PHBs Diff-Serv classification and PHBs
- Both TE tunnels and Aggregate RSVP reservations are controlled - Both TE tunnels and aggregate RSVP reservations are controlled
by "intelligent" devices on the edge of the "aggregation core" by "intelligent" devices on the edge of the "aggregation core"
RSVP Aggregation over MPLS TE tunnels July 2005
(Head-end and Tail-end in the case of TE tunnels, Aggregator (Head-end and Tail-end in the case of TE tunnels, Aggregator
and Deaggregator in the case of Aggregated RSVP reservations and Deaggregator in the case of aggregate RSVP reservations
- Both TE tunnels and Aggregate RSVP reservations are signaled - Both TE tunnels and aggregate RSVP reservations are signaled
using the RSVP protocol (with some extensions defined in [RSVP- using the RSVP protocol (with some extensions defined in [RSVP-
TE] and [DSTE-PROTO] respectively for TE tunnels and DS-TE TE] and [DSTE-PROTO] respectively for TE tunnels and DS-TE
tunnels). tunnels).
This document provides a detailed specification for performing This document provides a detailed specification for performing
aggregation of end-to-end RSVP reservations over MPLS TE tunnels aggregation of end-to-end RSVP reservations over MPLS TE tunnels
(which act as aggregated reservations in the core). This document (which act as aggregate reservations in the core). This document
builds on the RSVP Aggregation procedures defined in [RSVP-AGGR], and builds on the RSVP Aggregation procedures defined in [RSVP-AGG], and
only changes those where necessary to operate over TE tunnels. With only changes those where necessary to operate over TE tunnels. With
[RSVP-AGGR], a lot of responsibilities (such as mapping end-to-end [RSVP-AGG], a lot of responsibilities (such as mapping end-to-end
reservations to Aggregate reservations and resizing the Aggregate reservations to Aggregate reservations and resizing the Aggregate
reservations) are assigned to the Deaggregator (which is the reservations) are assigned to the Deaggregator (which is the
equivalent of the Tunnel Tail-end) while with TE, the tunnels are equivalent of the Tunnel Tail-end) while with TE, the tunnels are
controlled by the Tunnel Head-end. Hence, the main change over the controlled by the Tunnel Head-end. Hence, the main change over the
RSVP Aggregations procedures defined in [RSVP-AGGR] is to modify RSVP Aggregations procedures defined in [RSVP-AGG] is to modify these
these procedures to reassign responsibilities from the Deaggregator procedures to reassign responsibilities from the Deaggregator to the
to the Aggregator (i.e. the tunnel Head-end). Aggregator (i.e. the tunnel Head-end).
[LSP-HIER] defines how to aggregate MPLS TE Label Switched Paths [LSP-HIER] defines how to aggregate MPLS TE Label Switched Paths
(LSPs) by creating a hierarchy of such LSPs. This involves nesting of (LSPs) by creating a hierarchy of such LSPs. This involves nesting of
end-to-end LSPs into an aggregate LSP in the core (by using the label end-to-end LSPs into an aggregate LSP in the core (by using the label
stack construct). Since end-to-end TE LSPs are themselves signaled stack construct). Since end-to-end TE LSPs are themselves signaled
with RSVP-TE and reserve resources at every hop, this can be looked with RSVP-TE and reserve resources at every hop, this can be looked
at as a form of aggregation of RSVP(-TE) reservations over MPLS TE at as a form of aggregation of RSVP(-TE) reservations over MPLS TE
Tunnels. This document capitalizes on the similarities between Tunnels. This document capitalizes on the similarities between
nesting of TE LSPs over TE tunnels and RSVP aggregation over TE nesting of TE LSPs over TE tunnels and RSVP aggregation over TE
tunnels and reuses the procedures of [LSP-HIER] wherever possible. tunnels and reuses the procedures of [LSP-HIER] wherever possible.
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- Whereas RFC 2746 describes operation with IP tunnels, this - Whereas RFC 2746 describes operation with IP tunnels, this
draft describes operation over MPLS tunnels. One consequence of draft describes operation over MPLS tunnels. One consequence of
this difference is the need to deal with penultimate hop this difference is the need to deal with penultimate hop
popping (PHP). popping (PHP).
- MPLS-TE tunnels inherently reserve resources, whereas the - MPLS-TE tunnels inherently reserve resources, whereas the
tunnels in RFC 2746 do not have resource reservations by tunnels in RFC 2746 do not have resource reservations by
default. This leads to some simplifications in the current default. This leads to some simplifications in the current
draft. draft.
- There is exactly one reservation per MPLS-TE tunnel, whereas - There is exactly one reservation per MPLS-TE tunnel, whereas
RFC 2746 permits many reservations per tunnel. RFC 2746 permits many reservations per tunnel.
RSVP Aggregation over MPLS TE tunnels February 2006
- We have assumed in the current draft that a given MPLS-TE - We have assumed in the current draft that a given MPLS-TE
tunnel will carry reserved traffic and nothing but reserved tunnel will carry reserved traffic and nothing but reserved
traffic, which negates the requirement of RFC 2746 to traffic, which negates the requirement of RFC 2746 to
distinguish reserved and non-reserved traffic traversing the distinguish reserved and non-reserved traffic traversing the
same tunnel by using distinct encapsulations. same tunnel by using distinct encapsulations.
RSVP Aggregation over MPLS TE tunnels July 2005
- There may be several MPLS-TE tunnels that share common head and - There may be several MPLS-TE tunnels that share common head and
tail end routers, with head-end policy determining which tunnel tail end routers, with head-end policy determining which tunnel
is appropriate for a particular flow. This scenario does not is appropriate for a particular flow. This scenario does not
appear to be addressed in RFC 2746. appear to be addressed in RFC 2746.
At the same time, this draft does have many similarities with RFC At the same time, this draft does have many similarities with RFC
2746. MPLS-TE tunnels are "type 2 tunnels" in the nomenclature of RFC 2746. MPLS-TE tunnels are "type 2 tunnels" in the nomenclature of RFC
2746: 2746:
" "
The (logical) link may be able to promise that some overall The (logical) link may be able to promise that some overall
level of resources is available to carry traffic, but not to level of resources is available to carry traffic, but not to
allocate resources specifically to individual data flows. allocate resources specifically to individual data flows.
" "
Aggregation of end-to-end RSVP reservations over TE tunnels combines Aggregation of end-to-end RSVP reservations over TE tunnels combines
the benefits of [RSVP-AGGR] with the benefits of MPLS including the the benefits of [RSVP-AGG] with the benefits of MPLS including the
following: following:
- dynamic, topology-aware resource-based admission control can be - applications can benefit from dynamic, topology-aware resource-
provided to applications over any segment of the end to end based admission control over any segment of the end to end path
path including the core including the core
- as per regular RSVP behavior, RSVP does not impose any burden - as per regular RSVP behavior, RSVP does not impose any burden
on routers where such admission control is not needed (for on routers where such admission control is not needed (for
example if the links upstream and downstream of the MPLS TE example if the links upstream and downstream of the MPLS TE
core are vastly over-engineered compared to the core capacity, core are vastly over-engineered compared to the core capacity,
admission control is not required on these links and RSVP need admission control is not required on these over-engineered
not be processed on the corresponding router hops) links and RSVP need not be processed on the corresponding
- the core scalability is not affected (relative to the standard router hops)
MPLS TE deployment model) since the core remains unaware of - the core scalability is not affected (relative to the
end-to-end RSVP reservations and only has to maintain aggregate traditional MPLS TE deployment model) since the core remains
TE tunnels and since the datapath classification and scheduling unaware of end-to-end RSVP reservations and only has to
in the core relies purely on Diffserv mechanism (or more maintain aggregate TE tunnels and since the datapath
precisely MPLS Diffserv mechanisms as specified in [DIFF-MPLS]) classification and scheduling in the core relies purely on
Diffserv mechanism (or more precisely MPLS Diffserv mechanisms
as specified in [DIFF-MPLS])
- the aggregate reservation (and thus the traffic from the - the aggregate reservation (and thus the traffic from the
corresponding end to end reservations) can be network corresponding end to end reservations) can be network
engineered via the use of Constraint based routing (e.g. engineered via the use of Constraint based routing (e.g.
affinity, optimization on different metrics) and when needed affinity, optimization on different metrics) and when needed
can take advantage of resources on other paths than the can take advantage of resources on other paths than the
shortest path shortest path
- the aggregate reservations (and thus the traffic from the - the aggregate reservations (and thus the traffic from the
corresponding end to end reservations) can be protected against corresponding end to end reservations) can be protected against
failure through the use of MPLS Fast Reroute failure through the use of MPLS Fast Reroute
This document, like [RSVP-AGGR], covers aggregation of unicast RSVP Aggregation over MPLS TE tunnels February 2006
This document, like [RSVP-AGG], covers aggregation of unicast
sessions. Aggregation of multicast sessions is for further study. sessions. Aggregation of multicast sessions is for further study.
1.1. Changes from previous versions 1.1. Changes from previous versions
The significant changes from version draft-lefaucheur-rsvp-dste-02 The changes from version draft-ietf-tsvwg-rsvp-dste-00 to version
to version draft-ietf-tsvwg-rsvp-dste-00.txt of this draft are: draft-ietf-tsvwg-rsvp-dste-01 of this draft address comments from the
"RSVP Review team" and from the Working Group Last Call. The
RSVP Aggregation over MPLS TE tunnels July 2005 significant changes are:
- added text in multiple sub-sections of section 3 to describe
operations when the Aggregator and Deaggregator also behave as
IPsec security gateways.
- added text in section 3 to further clarify relationship with
[LSP-HIER]
- added text in section 8 to refer to some security
considerations of [LSP-HIER] which are applicable to this
document
- edits in section 3.2 about forwarding of E2E path
- edits in section 3.4 about processing of E2E Path
- edits in section 3.6 to describe operations in case of TE
tunnel mapping change
- added section 3.7 to clarify forwarding of E2E traffic by
Aggregator
- cleaned up usage of MUST/SHOULD/MAY
- clarifications and editorials.
The significant changes from version draft-lefaucheur-rsvp-dste-02
to version draft-ietf-tsvwg-rsvp-dste-00 of this draft were:
- added a SHOULD for use of Make-Before-Break when resizing TE - added a SHOULD for use of Make-Before-Break when resizing TE
tunnel tunnel
- added clarification text about E2E Resv hiding from Transit - added clarification text about E2E Resv hiding from Transit
LSRs LSRs
- added reference to [RSVP-AGG-IPSEC] in section 5. - added reference to [RSVP-GEN-AGG] in section 5.
- added definition of E2E reservation in section 2. - added definition of E2E reservation in section 2.
- removed the case where E2E reservation is a TE tunnel (already - removed the case where E2E reservation is a TE tunnel (already
covered in [LSP-HIER]) covered in [LSP-HIER])
The significant changes from version draft-lefaucheur-rsvp-dste-01 to The significant changes from version draft-lefaucheur-rsvp-dste-01 to
version draft-lefaucheur-rsvp-dste-02 of this draft are: version draft-lefaucheur-rsvp-dste-02 of this draft were:
- Alignment with RSVP operations of draft-ietf-mpls-lsp-hierarchy - Alignment with RSVP operations of draft-ietf-mpls-lsp-hierarchy
- Addition of an appendix providing an example usage scenario for - Addition of an appendix providing an example usage scenario for
information purposes information purposes
The significant changes from version draft-lefaucheur-rsvp-dste-00 to The significant changes from version draft-lefaucheur-rsvp-dste-00 to
version draft-lefaucheur-rsvp-dste-01 of this draft were: version draft-lefaucheur-rsvp-dste-01 of this draft were:
- added discussion of the relationship to RFC 2746 [RSVP-TUN] - added discussion of the relationship to RFC 2746 [RSVP-TUN]
- added discussion of mapping policy at aggregator - added discussion of mapping policy at aggregator
- added discussion of "RSVP proxy" behavior in conjunction with - added discussion of "RSVP proxy" behavior in conjunction with
the aggregation scheme described here the aggregation scheme described here
RSVP Aggregation over MPLS TE tunnels February 2006
- added discussion on TTL processing on Deaggregator - added discussion on TTL processing on Deaggregator
2. Definitions 2. Definitions
For readability, a number of definitions from [RSVP-AGGR] as well as For readability, a number of definitions from [RSVP-AGG] as well as
definitions for commonly used MPLS TE terms are provided here: definitions for commonly used MPLS TE terms are provided here:
Aggregator This is the router at the ingress edge of the Aggregator This is the process in (or associated with) the router
aggregation region (with respect to the end to end at the ingress edge of the aggregation region (with
RSVP reservation) and behaving in accordance with respect to the end to end RSVP reservation) and
[RSVP-AGG]. In this document, it is also the TE Tunnel behaving in accordance with [RSVP-AGG]. In this
Head-end. document, it is also the TE Tunnel Head-end.
Deaggregator This is the router at the egress edge of the Deaggregator This is the process in (or associated with) the router
aggregation region (with respect to the end to end at the egress edge of the aggregation region (with
RSVP reservation) and behaving in accordance with respect to the end to end RSVP reservation) and
[RSVP-AGG]. In this document, it is also the TE Tunnel behaving in accordance with [RSVP-AGG]. In this
Tail-end document, it is also the TE Tunnel Tail-end
E2E End to end E2E End to end
E2E reservation This is an RSVP reservation such that: E2E reservation This is an RSVP reservation such that:
(i) corresponding Path messages are initiated (i) corresponding Path messages are initiated
upstream of the Aggregator and terminated upstream of the Aggregator and terminated
downstream of the Deaggregator, and downstream of the Deaggregator, and
RSVP Aggregation over MPLS TE tunnels July 2005
(ii) corresponding Resv messages are initiated (ii) corresponding Resv messages are initiated
downstream of the Deaggregator and downstream of the Deaggregator and
terminated upstream of the Aggregator, and terminated upstream of the Aggregator, and
(iii) this RSVP reservation is to be aggregated (iii) this RSVP reservation is to be aggregated
over an MPLS TE tunnel between the over an MPLS TE tunnel between the
Aggregator and Deaggregator. Aggregator and Deaggregator.
An E2E RSVP reservation may be a per-flow An E2E RSVP reservation may be a per-flow
reservation. Alternatively, the E2E reservation reservation. Alternatively, the E2E reservation
may itself be an aggregate reservation of various may itself be an aggregate reservation of various
types (e.g. Aggregate IP reservation, Aggregate types (e.g. Aggregate IP reservation, Aggregate
IPsec reservation). See section 4 and 5 for more IPsec reservation). See section 4 and 5 for more
details on the types of E2E RSVP reservations. As details on the types of E2E RSVP reservations. As
per regular RSVP operations, E2E RSVP reservations per regular RSVP operations, E2E RSVP reservations
are unidirectional. are unidirectional.
Head-end Head-end
This is the Label Switch Router responsible for This is the Label Switch Router responsible for
establishing, maintaining and tearing-off a given TE establishing, maintaining and tearing down a given TE
tunnel. tunnel.
Tail-end Tail-end
This is the Label Switch Router responsible for This is the Label Switch Router responsible for
terminating a given TE tunnel terminating a given TE tunnel
RSVP Aggregation over MPLS TE tunnels February 2006
Transit LSR This is a Label Switch router that is on the path of a Transit LSR This is a Label Switch router that is on the path of a
given TE tunnel and is neither the Head-end nor the given TE tunnel and is neither the Head-end nor the
Tail-end Tail-end
3. Operations of RSVP Aggregation over TE with pre-established Tunnels 3. Operations of RSVP Aggregation over TE with pre-established Tunnels
[RSVP-AGG] supports operations both in the case where aggregate RSVP [RSVP-AGG] supports operations both in the case where aggregate RSVP
reservations are pre-established and in the case where Aggregating reservations are pre-established and in the case where Aggregators
and De-aggregating routers have to dynamically discover each other and Deaggregators have to dynamically discover each other and
and dynamically establish the necessary Aggregated RSVP reservations. dynamically establish the necessary aggregate RSVP reservations.
Similarly, RSVP Aggregation over TE tunnels could operate both in the Similarly, RSVP Aggregation over TE tunnels could operate both in the
case where the TE tunnels are pre-established and in the case where case where the TE tunnels are pre-established and in the case where
the tunnels need to be dynamically established. the tunnels need to be dynamically established.
In this document we provide a detailed description of the procedures In this document we provide a detailed description of the procedures
in the case where TE tunnels are already established. These in the case where TE tunnels are already established. These
procedures are based on those defined in [LSP-HIER]. procedures are based on those defined in [LSP-HIER]. The routing
aspects discussed in section 3 of [LSP-HIER] are not relevant here
because those aim at allowing the constraint based routing of end-to-
end TE LSPs to take into account the (aggregate) TE tunnels. In the
present document, the end-to-end RSVP reservations to be aggregated
over the TE tunnels rely on regular SPF routing. However, as already
mentioned in [LSP-HIER], we note that a TE Tunnel may be advertised
into ISIS or OSPF, to be used in normal SPF by nodes upstream of the
Aggregator. This would affect SPF routing and thus routing of end-to-
end RSVP reservations. The control of aggregation boundaries
discussed in section 6 of [LSP-HIER] is also not relevant here. This
uses information exchanged in GMPLS protocols to dynamically discover
the aggregation boundary. In this document, TE tunnels are pre-
established, so that the aggregation boundary can be easily inferred.
The signaling aspects discussed in section 6.2 of [LSP-HIER] apply to
the establishment/termination of the aggregate TE tunnels when this
is triggered by GMPLS mechanisms (e.g. as a result of an end-to-end
TE LSP establishment request received at the aggregation boundary) .
As this document assumes pre-established tunnels, those aspects are
not relevant here. The signaling aspects discussed in section 6.1 of
[LSP-HIER] relate to the establishment/maintenance of the end-to-end
TE LSPs over the aggregate TE tunnel. This document describes how to
use the same procedures as those specified in section 6.1 of [LSP-
HIER], but for the establishment of end-to-end RSVP reservations
(instead of end-to-end TE LSPs) over the TE tunnels. This is covered
further in section 3 of the present document.
Pre-establishment of the TE tunnels may be triggered by any Pre-establishment of the TE tunnels may be triggered by any
mechanisms including for example manual configuration or automatic mechanisms including for example manual configuration or automatic
establishment of a TE tunnel mesh through dynamic discovery of TE establishment of a TE tunnel mesh through dynamic discovery of TE
Mesh membership as allowed in [AUTOMESH]. Mesh membership as allowed in [AUTOMESH].
RSVP Aggregation over MPLS TE tunnels February 2006
Procedures in the case of dynamically established TE tunnels are for Procedures in the case of dynamically established TE tunnels are for
further studies. further studies.
RSVP Aggregation over MPLS TE tunnels July 2005
3.1. Reference Model 3.1. Reference Model
I----I I----I I----I I----I
H--I R I\ I-----I I------I /I R I--H H--I R I\ I-----I I------I /I R I--H
H--I I\\I I I---I I I//I I--H H--I I\\I I I---I I I//I I--H
I----I \I He/ I I T I I Te/ I/ I----I I----I \I He/ I I T I I Te/ I/ I----I
I Agg I=======================I Deag I I Agg I=======================I Deag I
/I I I I I I\ /I I I I I I\
H--------//I I I---I I I\\--------H H--------//I I I---I I I\\--------H
H--------/ I-----I I------I \--------H H--------/ I-----I I------I \--------H
skipping to change at page 8, line 30 skipping to change at page 9, line 33
He/Agg = TE tunnel Head-end/Aggregator He/Agg = TE tunnel Head-end/Aggregator
Te/Deag = TE tunnel Tail-end/Deaggregator Te/Deag = TE tunnel Tail-end/Deaggregator
T = Transit LSR T = Transit LSR
-- = E2E RSVP reservation -- = E2E RSVP reservation
== = TE Tunnel == = TE Tunnel
3.2. Receipt of E2E Path message By the Aggregator 3.2. Receipt of E2E Path message By the Aggregator
The first event is the arrival of the E2E Path message at the The first event is the arrival of the E2E Path message at the
Aggregator. Standard RSVP procedures are followed for this path Aggregator. The Aggregator MUST follow traditional RSVP procedures
message (including update of the PHOP field to a local Aggregator for processing of this E2E path message augmented with the extensions
address) augmented with the extensions documented in this section. documented in this section.
The Aggregator first attempts to map the E2E reservation onto a TE The Aggregator MUST first attempt to map the E2E reservation onto a
tunnel. This decision is made in accordance with routing information TE tunnel. This decision is made in accordance with routing
as well as any local policy information that may be available at the information as well as any local policy information that may be
Aggregator. Examples of such policies appear in the following available at the Aggregator. Examples of such policies appear in the
paragraphs. Just for illustration purposes, among many other criteria, following paragraphs. Just for illustration purposes, among many
such mapping policies might take into account the Intserv service other criteria, such mapping policies might take into account the
type, the Application Identity [RSVP-APPID] and/or the signaled Intserv service type, the Application Identity [RSVP-APPID] and/or
preemption [RSVP-PREEMP] of the E2E reservation (for example, the the signaled preemption [RSVP-PREEMP] of the E2E reservation (for
aggregator may take into account the E2E reservations RSVP preemption example, the aggregator may take into account the E2E reservations
priority and the MPLS TE Tunnel set-up and/or hold priorities when RSVP preemption priority and the MPLS TE Tunnel set-up and/or hold
mapping the E2E reservation onto an MPLS TE tunnel). priorities when mapping the E2E reservation onto an MPLS TE tunnel).
There are situations where the Aggregator is able to make a final There are situations where the Aggregator is able to make a final
mapping decision. That would be the case, for example, if there is a mapping decision. That would be the case, for example, if there is a
single TE tunnel towards the destination and if the policy is to map single TE tunnel towards the destination and if the policy is to map
any E2E RSVP reservation onto TE Tunnels. any E2E RSVP reservation onto TE Tunnels.
RSVP Aggregation over MPLS TE tunnels February 2006
There are situations where the Aggregator is not able to make a final There are situations where the Aggregator is not able to make a final
determination. That would be the case, for example, if routing determination. That would be the case, for example, if routing
RSVP Aggregation over MPLS TE tunnels July 2005
identifies two DS-TE tunnels towards the destination, one belonging identifies two DS-TE tunnels towards the destination, one belonging
to DS-TE Class-Type 1 and one to Class-Type 0, if the policy is to to DS-TE Class-Type 1 and one to Class-Type 0, if the policy is to
map Intserv Guaranteed Services reservations to a Class-Type 1 tunnel map Intserv Guaranteed Services reservations to a Class-Type 1 tunnel
and Intserv Controlled Load reservations to a Class-Type 0 tunnel, and Intserv Controlled Load reservations to a Class-Type 0 tunnel,
and if the E2E RSVP Path message advertises both Guaranteed Service and if the E2E RSVP Path message advertises both Guaranteed Service
and Controlled Load. and Controlled Load.
Whether final or tentative, the Aggregator makes a mapping decision Whether final or tentative, the Aggregator makes a mapping decision
and selects a TE tunnel. Before forwarding the E2E Path message and selects a TE tunnel. Before forwarding the E2E Path message
towards the receiver, the Aggregator should update the ADSPEC inside towards the receiver, the Aggregator SHOULD update the ADSPEC inside
the E2E Path message to reflect the impact of the MPLS TE cloud onto the E2E Path message to reflect the impact of the MPLS TE cloud onto
the QoS achievable by the E2E flow. This update is a local matter and the QoS achievable by the E2E flow. This update is a local matter and
may be based on configured information, on information available in may be based on configured information, on information available in
the MPLS TE topology database, on the current TE tunnel path, on the MPLS TE topology database, on the current TE tunnel path, on
information collected via RSVP-TE signaling, or combinations of those. information collected via RSVP-TE signaling, or combinations of those.
The Aggregator then forwards the E2E Path message. In accordance with The Aggregator MUST then forward the E2E Path message to the
[LSP-HIER], the E2E Path message is: Deaggregator (which is the tail-end of the selected TE tunnel). In
- sent with an IF_ID RSVP_HOP object instead of an RSVP_HOP accordance with [LSP-HIER], the Aggregator MUST send the E2E Path
object. The data interface identification identifies the TE message with an IF_ID RSVP_HOP object instead of an RSVP_HOP object.
Tunnel The data interface identification MUST identify the TE Tunnel.
- addressed directly to the Deaggregator. The destination address
of the E2E Path message is set to the Deaggregator address and The preferred method for the Aggregator to send the E2E Path message
the Router Alert is not set. Thus, the E2E Path message will is to address it directly to the Deaggregator by setting the
not be visible to Transit routers along the path of the TE destination address in the IP Header of the E2E Path message to the
tunnel. Thus, in contrast to the procedures of [RSVP-AGGR], the Deaggregator address. The Router Alert is not set in the E2E Path
IP Protocol number need not be modified to "RSVP-E2E-IGNORE"; message.
it is left as is (indicating "RSVP").
An alternate method for the Aggregator to send the E2E Path is to
encapsulate the E2E Path message in an IP tunnel or in the TE tunnel
itself and unicast the E2E Path message to the Deaggregator, without
the Router Alert option.
With both methods, the Router Alert is not set. Thus, the E2E Path
message will not be visible to routers along the path from the
Aggregator to the Deaggregator. Therefore, in contrast to the
procedures of [RSVP-AGG], the IP Protocol number need not be modified
to "RSVP-E2E-IGNORE"; it MUST be left as is (indicating "RSVP") by
the Aggregator.
In some environments, the Aggregator and Deaggregator MAY also act as
IPsec Security Gateways in order to provide IPsec protection to E2E
traffic when it transits between the Aggregator and the Deaggregator.
In that case, to transmit the E2E Path message to the Deaggregator,
the Aggregator MUST send the E2E Path message into the relevant IPsec
tunnel terminating on the Deaggregator.
RSVP Aggregation over MPLS TE tunnels February 2006
3.3. Handling of E2E Path message By Transit LSRs 3.3. Handling of E2E Path message By Transit LSRs
Since the E2E Path message is addressed directly to the Deaggreagtor Since the E2E Path message is addressed directly to the Deaggregator
and does not have Router Alert set, it is hidden from all transit and does not have Router Alert set, it is hidden from all transit
LSRs. LSRs.
3.4. Receipt of E2E Path Message by Deaggregator 3.4. Receipt of E2E Path Message by Deaggregator
On receipt of the E2E Path message addressed to it, the Deaggregator On receipt of the E2E Path message addressed to it, the Deaggregator
will notice that the IP Protocol number is set to "RSVP" and will will notice that the IP Protocol number is set to "RSVP" and will
thus perform RSVP processing of the E2E Path message. thus perform RSVP processing of the E2E Path message.
As with [LSP-HIER], the IP TTL vs. RSVP TTL check must not be made. As with [LSP-HIER], the IP TTL vs. RSVP TTL check MUST not be made.
The Deaggregator is informed that this check must not be made because The Deaggregator is informed that this check is not to be made
of the presence of the IF_ID RSVP HOP object. As with [LSP-HIER], the because of the presence of the IF_ID RSVP HOP object.
following checks should be made by the receiver Y of the IF_ID
RSVP_HOP object:
RSVP Aggregation over MPLS TE tunnels July 2005 The Deaggregator MAY support the option to perform the following
checks (defined in [LSP-HIER]) by the receiver Y of the IF_ID
RSVP_HOP object:
1. Make sure that the data interface identified in the IF_ID 1. Make sure that the data interface identified in the IF_ID
RSVP_HOP object actually terminates on Y. RSVP_HOP object actually terminates on Y.
2. Find the "other end" of the above data interface, say X. 2. Find the "other end" of the above data interface, say X.
Make sure that the PHOP in the IF_ID RSVP_HOP object is a Make sure that the PHOP in the IF_ID RSVP_HOP object is a
control channel address that belongs to the same node as X. control channel address that belongs to the same node as X.
The information necessary to perform these checks may not always be
available to the Deaggregator. Hence, the Deaggregator MUST support
operations in such environments where the checks cannot be made.
The Deaggregator MUST forward the E2E Path downstream towards the
receiver. In doing so, the Deaggregator sets the destination address
in the IP header of the E2E Path message to the IP address found in
the destination address field of the Session object. The Deaggregator
also sets the Router Alert.
An E2E PathErr sent by the Deaggregator in response to the E2E Path
message (which contains an IF_ID RSVP_HOP object) SHOULD contain an
IF_ID RSVP_HOP object.
3.5. Handling of E2E Resv Message by Deaggregator 3.5. Handling of E2E Resv Message by Deaggregator
The Deaggregator follows standard RSVP procedures on receipt of the As per regular RSVP operations, after receipt of the E2E Path, the
E2E Resv message. This includes performing admission control for the receiver generates an E2E Resv message which travels upstream hop-by-
segment downstream of the Deaggregator and forwarding the E2E Resv hop towards the sender.
message to the PHOP signaled earlier in the E2E Path message and
which identifies the Aggregator. Since the E2E Resv message is RSVP Aggregation over MPLS TE tunnels February 2006
directly addressed to the Aggregator and does not carry the Router
Alert option (as per regular RSVP Resv procedures), the E2E Resv On receipt of the E2E Resv, the Deaggregator MUST follow traditional
message is hidden from the transit LSRs which handle the E2E Resv RSVP procedures on receipt of the E2E Resv message. This includes
message as a regular IP packet. performing admission control for the segment downstream of the
Deaggregator and forwarding the E2E Resv message to the PHOP signaled
earlier in the E2E Path message and which identifies the Aggregator.
Since the E2E Resv message is directly addressed to the Aggregator
and does not carry the Router Alert option (as per traditional RSVP
Resv procedures), the E2E Resv message is hidden from the routers
between the Deaggregator and the Aggregator which, therefore, handle
the E2E Resv message as a regular IP packet.
If the Aggregator and Deaggregator are also acting as IPsec Security
Gateways, the Deaggregator MUST send the E2E Resv message into the
relevant IPsec tunnel terminating on the Aggregator.
3.6. Handling of E2E Resv Message by the Aggregator 3.6. Handling of E2E Resv Message by the Aggregator
The Aggregator is responsible for ensuring that there is sufficient The Aggregator is responsible for ensuring that there is sufficient
bandwidth available and reserved over the appropriate TE tunnel to bandwidth available and reserved over the appropriate TE tunnel to
the Deaggregator for the E2E reservation. the Deaggregator for the E2E reservation.
On receipt of the E2E Resv message, the Aggregator first performs the On receipt of the E2E Resv message, the Aggregator MUST first perform
final mapping onto the final TE tunnels (if it was only a tentative the final mapping onto the final TE tunnel (if the previous mapping
mapping). If needed the Aggregator updates the ADSPEC and immediately was only a tentative one).
generates an E2E Path refresh in order to provide the accurate ADSPEC
information to the receiver as soon as possible.
The aggregator then calculates the size of the resource request using If the tunnel did not change during the final mapping, the Aggregator
standard RSVP procedures. That is, it follows the procedures in continues processing of the E2E Resv as described in the four
following paragraphs.
The aggregator calculates the size of the resource request using
traditional RSVP procedures. That is, it follows the procedures in
[RFC2205] to determine the resource requirements from the Sender [RFC2205] to determine the resource requirements from the Sender
Tspec and the Flowspec contained in the Resv. It them compares the Tspec and the Flowspec contained in the Resv. Then it compares the
resource requests with the available resources of the selected TE resource request with the available resources of the selected TE
tunnel. tunnel.
If sufficient bandwidth is available on the final TE tunnel, the If sufficient bandwidth is available on the final TE tunnel, the
Aggregator updates its internal understanding of how much of the TE Aggregator MUST update its internal understanding of how much of the
Tunnel is in use and forwards the E2E Resv messages to the TE Tunnel is in use and MUST forward the E2E Resv messages to the
corresponding PHOP. corresponding PHOP.
As noted in [RSVP-AGGR], a range of policies may be applied to the As noted in [RSVP-AGG], a range of policies MAY be applied to the re-
re-sizing of the aggregate reservation (in this case, the TE tunnel.) sizing of the aggregate reservation (in this case, the TE tunnel.)
For example, the policy may be that the reserved bandwidth of the For example, the policy may be that the reserved bandwidth of the
tunnel can only be changed by configuration. More dynamic policies tunnel can only be changed by configuration. More dynamic policies
are also possible, whereby the aggregator may attempt to increase the are also possible, whereby the aggregator may attempt to increase the
reserved bandwidth of the tunnel in response to the amount of reserved bandwidth of the tunnel in response to the amount of
RSVP Aggregation over MPLS TE tunnels July 2005 RSVP Aggregation over MPLS TE tunnels February 2006
allocated bandwidth that has been used by E2E reservations. allocated bandwidth that has been used by E2E reservations.
Furthermore, to avoid the delay associated with the increase of the Furthermore, to avoid the delay associated with the increase of the
Tunnel size, the Aggregator may attempt to anticipate the increases Tunnel size, the Aggregator may attempt to anticipate the increases
in demand and adjust the TE tunnel size ahead of actual needs by E2E in demand and adjust the TE tunnel size ahead of actual needs by E2E
reservations. In order to reduce disruptions, the aggregator SHOULD reservations. In order to reduce disruptions, the aggregator SHOULD
use "make-before-break" procedures as described in [RSVP-TE] to alter use "make-before-break" procedures as described in [RSVP-TE] to alter
the TE tunnel bandwidth". the TE tunnel bandwidth".
If sufficient bandwidth is not available on the final TE Tunnel, the If sufficient bandwidth is not available on the final TE Tunnel, the
Aggregator must follow the normal RSVP procedure for a reservation Aggregator MUST follow the normal RSVP procedure for a reservation
being placed with insufficient bandwidth to support this reservation. being placed with insufficient bandwidth to support this reservation.
That is, the reservation is not installed and a ResvError is sent That is, the reservation is not installed and a ResvError is sent
back towards the receiver. back towards the receiver.
3.7. Removal of E2E reservations If the tunnel did change during the final mapping, the Aggregator
MUST first resend to the Deaggregator an E2E Path message with the
IF_ID RSVP_HOP data interface identification identifying the final TE
Tunnel. If needed, the ADSPEC information in this E2E Path message
SHOULD be updated. Then the Aggregator MUST
- either drop the E2E Resv message
- or proceed with the processing of the E2E Resv in the same
manner as in the case where the tunnel did not change and
described above.
In the former case, admission control over the final TE tunnel (and
forwarding of E2E Resv message upstream towards the sender) would
only occur when the Aggregator receives the subsequent E2E Resv
message (that will be sent by the Deaggregator in response to the
resent E2E Path). In the latter case, admission control over the
final Tunnel is carried out by Aggregator right away and if
successful the E2E Resv message is generated upstream towards the
sender.
3.7. Forwarding of E2E traffic by Aggregator
When the Aggregator receives a data packet belonging to an E2E
reservations currently mapped over a given TE tunnel, the Aggregator
MUST encapsulate the packet into that TE tunnel.
If the Aggregator and Deaggregator are also acting as IPsec Security
Gateways, the Aggregator MUST also encapsulate the data packet into
the relevant IPsec tunnel terminating on the Deaggregator before
transmission into the MPLS TE tunnel.
3.8. Removal of E2E reservations
RSVP Aggregation over MPLS TE tunnels February 2006
E2E reservations are removed in the usual way via PathTear, ResvTear, E2E reservations are removed in the usual way via PathTear, ResvTear,
timeout, or as the result of an error condition. When a reservation timeout, or as the result of an error condition. When a reservation
is removed, the Aggregator updates its local view of the is removed, the Aggregator MUST update its local view of the
resources available on the corresponding TE tunnel accordingly. resources available on the corresponding TE tunnel accordingly.
3.8. Removal of TE Tunnel 3.9. Removal of TE Tunnel
Should a TE Tunnel go away (presumably due to a configuration change, Should a TE Tunnel go away (presumably due to a configuration change,
route change, or policy event), the aggregator behaves much like a route change, or policy event), the aggregator behaves much like a
conventional RSVP router in the face of a link failure. That is, it conventional RSVP router in the face of a link failure. That is, it
may try to forward the Path messages onto another tunnel, if routing may try to forward the Path messages onto another tunnel, if routing
and policy permit, or it may send Path_Error messages to the sender and policy permit, or it may send Path_Error messages to the sender
if no suitable tunnel exists. In case the Path messages are forwarded if no suitable tunnel exists. In case the Path messages are forwarded
onto another tunnel which terminates on a different Deaggregator, or onto another tunnel which terminates on a different Deaggregator, or
the reservation is torn-down via Path Error messages, the reservation the reservation is torn-down via Path Error messages, the reservation
state established on the router acting as the Deaggregator before the state established on the router acting as the Deaggregator before the
TE tunnel went away, will time out since it will no longer be TE tunnel went away, will time out since it will no longer be
refreshed. refreshed.
RSVP Aggregation over MPLS TE tunnels July 2005 RSVP Aggregation over MPLS TE tunnels February 2006
3.9. Example Signaling Flow 3.10. Example Signaling Flow
Aggregator Deaggregator Aggregator Deaggregator
(*) (*)
RSVP-TE Path RSVP-TE Path
=========================> =========================>
RSVP-TE Resv RSVP-TE Resv
<========================= <=========================
(**) (**)
skipping to change at page 12, line 48 skipping to change at page 15, line 48
(**) TE Tunnel(s) are pre-established (**) TE Tunnel(s) are pre-established
(1) Aggregator tentatively selects the TE tunnel and forwards (1) Aggregator tentatively selects the TE tunnel and forwards
E2E path to Deaggregator E2E path to Deaggregator
(2) Deaggregator forwards the E2E Path towards receiver (2) Deaggregator forwards the E2E Path towards receiver
(3) Deaggregator forwards the E2E Resv to the Aggregator (3) Deaggregator forwards the E2E Resv to the Aggregator
(4) Aggregator selects final TE tunnel, check there is (4) Aggregator selects final TE tunnel, checks that there is
sufficient bandwidth on TE tunnel and forwards E2E Resv to sufficient bandwidth on TE tunnel and forwards E2E Resv to
PHOP
RSVP Aggregation over MPLS TE tunnels July 2005 RSVP Aggregation over MPLS TE tunnels February 2006
PHOP. If final tunnel is different from tunnel tentatively
selected, the Aggregator re-sends an E2E Path.
4. IPv4 and IPv6 Applicability 4. IPv4 and IPv6 Applicability
The procedures defined in this document are applicable to all the The procedures defined in this document are applicable to all the
following cases: following cases:
(1) Aggregation of E2E IPv4 RSVP reservations over IPv4 TE (1) Aggregation of E2E IPv4 RSVP reservations over IPv4 TE
Tunnels Tunnels
(2) Aggregation of E2E IPv6 RSVP reservations over IPv6 TE (2) Aggregation of E2E IPv6 RSVP reservations over IPv6 TE
Tunnels Tunnels
skipping to change at page 13, line 31 skipping to change at page 16, line 34
tunnels, provided a mechanism is used by the Aggregator and tunnels, provided a mechanism is used by the Aggregator and
Deaggregator for routing IPv4 traffic over IPv6 MPLS. Deaggregator for routing IPv4 traffic over IPv6 MPLS.
5. E2E Reservations Applicability 5. E2E Reservations Applicability
The procedures defined in this document are applicable to many types The procedures defined in this document are applicable to many types
of E2E RSVP reservations including the following cases: of E2E RSVP reservations including the following cases:
(1) the E2E RSVP reservation is a per-flow reservation where the (1) the E2E RSVP reservation is a per-flow reservation where the
flow is characterized by the usual 5-tuple flow is characterized by the usual 5-tuple
(2) the E2E reservation is an aggregate reservation for multiple (2) the E2E reservation is an aggregate reservation for multiple
flows as described in [RSVP-AGG] where the set of flows is flows as described in [RSVP-AGG] or [RSVP-GEN-AGG] where the
characterized by the <source address, destination address, set of flows is characterized by the <source address,
DSCP> destination address, DSCP>
(3) the E2E reservation is a reservation for an IPSec protected (3) the E2E reservation is a reservation for an IPsec protected
flow. For example, where the flow is characterized by the flow. For example, where the flow is characterized by the
<source address, destination address, SPI> as described in <source address, destination address, SPI> as described in
[RSVP-IPSEC] [RSVP-IPSEC]
(4) the E2E reservation is an aggregate reservation for multiple IPsec
flows and where the set of flows are protected by IPSec
[RSVP-AGG-IPSEC]
6. Example Deployment Scenarios 6. Example Deployment Scenarios
6.1. Voice and Video Reservations Scenario 6.1. Voice and Video Reservations Scenario
An example application of the procedures specified in this document An example application of the procedures specified in this document
is admission control of voice and video in environments with very is admission control of voice and video in environments with very
high numbers of hosts. In the example illustrated below, hosts high numbers of hosts. In the example illustrated below, hosts
generate end-to-end per-flow reservations for each of their video generate end-to-end per-flow reservations for each of their video
streams associated with a video-conference, each of their audio streams associated with a video-conference, each of their audio
streams associated with a video-conference and each of their voice streams associated with a video-conference and each of their voice
calls. These reservations are aggregated over MPLS DS-TE tunnels over
RSVP Aggregation over MPLS TE tunnels July 2005 RSVP Aggregation over MPLS TE tunnels February 2006
calls. These reservations are aggregated over MPLS DS-TE tunnels over
the packet core. The mapping policy defined by the user maybe that the packet core. The mapping policy defined by the user maybe that
all the reservations for audio and voice streams are mapped onto DS- all the reservations for audio and voice streams are mapped onto DS-
TE tunnels of Class-Type 1 while reservations for video streams are TE tunnels of Class-Type 1 while reservations for video streams are
mapped onto DS-TE tunnels of Class-Type 0. mapped onto DS-TE tunnels of Class-Type 0.
------ ------ ------ ------
I H I# ------- -------- #I H I I H I# ------- -------- #I H I
I I\#I I ----- I I#/I I I I\#I I ----- I I#/I I
-----I \I Agg I I T I I Deag I/ ------ -----I \I Agg I I T I I Deag I/ ------
I I==========================I I I I==========================I I
skipping to change at page 15, line 5 skipping to change at page 18, line 5
environments. A Trunk VoIP Gateway may generate one aggregate RSVP environments. A Trunk VoIP Gateway may generate one aggregate RSVP
reservation for all the calls in place towards another given remote reservation for all the calls in place towards another given remote
Trunk VoIP Gateway (with resizing of this aggregate reservation in a Trunk VoIP Gateway (with resizing of this aggregate reservation in a
step function depending on current number of calls). In turn, these step function depending on current number of calls). In turn, these
reservations may be aggregated over MPLS TE tunnels over the packet reservations may be aggregated over MPLS TE tunnels over the packet
core so that tunnel Head-ends act as Aggregators and perform core so that tunnel Head-ends act as Aggregators and perform
admission control of Trunk Gateway reservations into MPLS TE Tunnels. admission control of Trunk Gateway reservations into MPLS TE Tunnels.
The MPLS TE tunnels may be protected by MPLS Fast Reroute. The MPLS TE tunnels may be protected by MPLS Fast Reroute.
This scenario is illustrated below: This scenario is illustrated below:
RSVP Aggregation over MPLS TE tunnels July 2005 RSVP Aggregation over MPLS TE tunnels February 2006
------ ------ ------ ------
I GW I\ ------- -------- /I GW I I GW I\ ------- -------- /I GW I
I I\\I I ----- I I//I I I I\\I I ----- I I//I I
-----I \I Agg I I T I I Deag I/ ------ -----I \I Agg I I T I I Deag I/ ------
I I==========================I I I I==========================I I
------ /I I I I I I\ ------ ------ /I I I I I I\ ------
I GW I//I I ----- I I\\I GW I I GW I//I I ----- I I\\I GW I
I I/ ------- -------- \I I I I/ ------- -------- \I I
------ ------ ------ ------
skipping to change at page 16, line 5 skipping to change at page 19, line 5
Resv message. Proxying the Resv involves installing state in the node Resv message. Proxying the Resv involves installing state in the node
doing the proxy i.e. the proxying node should act as if it had doing the proxy i.e. the proxying node should act as if it had
received a Resv from the true endpoint. This involves reserving received a Resv from the true endpoint. This involves reserving
resources (if required), sending periodic refreshes of the Resv resources (if required), sending periodic refreshes of the Resv
message and tearing down the reservation if the Path is torn down." message and tearing down the reservation if the Path is torn down."
Hence, when behaving as the RSVP Proxy, the RSVP Aggregator may Hence, when behaving as the RSVP Proxy, the RSVP Aggregator may
effectively perform resource reservation over the MPLS TE Tunnel (and effectively perform resource reservation over the MPLS TE Tunnel (and
hence over the whole segment between the RSVP Aggregator and the RSVP hence over the whole segment between the RSVP Aggregator and the RSVP
RSVP Aggregation over MPLS TE tunnels July 2005 RSVP Aggregation over MPLS TE tunnels February 2006
Deaggregator) even if the RSVP signaling only takes place upstream of Deaggregator) even if the RSVP signaling only takes place upstream of
the MPLS TE Tunnel (i.e. between the host and the RSVP aggregator). the MPLS TE Tunnel (i.e. between the host and the RSVP aggregator).
Also, the RSVP Proxy can generate the Path message on behalf of the Also, the RSVP Proxy can generate the Path message on behalf of the
remote source host in order to achieve reservation in the return remote source host in order to achieve reservation in the return
direction (i.e. from RSVP aggregator/Deaggregator to host). direction (i.e. from RSVP aggregator/Deaggregator to host).
The resulting Signaling Flow is illustrated below, covering The resulting Signaling Flow is illustrated below, covering
reservations for both directions: reservations for both directions:
skipping to change at page 17, line 5 skipping to change at page 20, line 5
(3)(iii) : Aggregator/Deaggregator/Proxy generates the Path message (3)(iii) : Aggregator/Deaggregator/Proxy generates the Path message
towards Host for reservation in return direction. The actual trigger towards Host for reservation in return direction. The actual trigger
for this depends on the actual RSVP proxy solution. As an example, for this depends on the actual RSVP proxy solution. As an example,
(3) and (iii) may simply be triggered respectively by (1) and (i). (3) and (iii) may simply be triggered respectively by (1) and (i).
Note that the details of the signaling flow may vary slightly Note that the details of the signaling flow may vary slightly
depending on the actual approach used for RSVP Proxy. For example, if depending on the actual approach used for RSVP Proxy. For example, if
the [L-RSVP] approach was used instead of [RSVP-PROXY], an additional the [L-RSVP] approach was used instead of [RSVP-PROXY], an additional
PathRequest message would be needed from host to PathRequest message would be needed from host to
RSVP Aggregation over MPLS TE tunnels July 2005 RSVP Aggregation over MPLS TE tunnels February 2006
Aggregator/Deaggregator/Proxy in order to trigger the generation of Aggregator/Deaggregator/Proxy in order to trigger the generation of
the Path message for return direction. the Path message for return direction.
But regardless of the details of the call flow and of the actual RSVP But regardless of the details of the call flow and of the actual RSVP
Proxy approach, RSVP proxy may optionally be deployed in combination Proxy approach, RSVP proxy may optionally be deployed in combination
with RSVP Aggregation over MPLS TE Tunnels, in such a way which with RSVP Aggregation over MPLS TE Tunnels, in such a way which
ensures (when used on both the Host-Aggregator and Deaggregator-Host ensures (when used on both the Host-Aggregator and Deaggregator-Host
sides, and when both end systems support RSVP) that: sides, and when both end systems support RSVP) that:
skipping to change at page 17, line 39 skipping to change at page 20, line 39
are pre-conditions for voice call establishment), are pre-conditions for voice call establishment),
particularly in the case where the MPLS TE tunnels span particularly in the case where the MPLS TE tunnels span
long distances with high propagation delays. long distances with high propagation delays.
8. Security Considerations 8. Security Considerations
The security issues inherent to the use of RSVP, RSVP Aggregation and The security issues inherent to the use of RSVP, RSVP Aggregation and
MPLS TE apply. Those can be addressed as discussed in [RSVP], [RSVP- MPLS TE apply. Those can be addressed as discussed in [RSVP], [RSVP-
AGG] and [RSVP-TE]. AGG] and [RSVP-TE].
Section 7 of [LSP-HIER] discusses security considerations stemming
from the fact that the implicit assumption of a binding between data
interface and the interface over which a control message is sent is
no longer valid. These security considerations are equally applicable
to the present document.
In addition, in the case where the Aggregators dynamically resize the In addition, in the case where the Aggregators dynamically resize the
TE tunnels based on the current level of reservation, there are risks TE tunnels based on the current level of reservation, there are risks
that the TE tunnels used for RSVP aggregation hog resources in the that the TE tunnels used for RSVP aggregation hog resources in the
core which could prevent other TE Tunnels from being established. core which could prevent other TE Tunnels from being established.
There are also potential risks that such resizing results in There are also potential risks that such resizing results in
significant computation and signaling as well as churn on tunnel significant computation and signaling as well as churn on tunnel
paths. Such risks can be mitigated by configuration options allowing paths. Such risks can be mitigated by configuration options allowing
control of TE tunnel dynamic resizing (maximum Te tunnel size, control of TE tunnel dynamic resizing (maximum Te tunnel size,
maximum resizing frequency,...) and/or possibly by the use of TE maximum resizing frequency,...) and/or possibly by the use of TE
preemption. preemption.
RSVP Aggregation over MPLS TE tunnels February 2006
If the Aggregator and Deaggregator are also acting as IPsec Security
Gateways, the Security Considerations of [SEC-ARCH] apply.
9. IANA Considerations 9. IANA Considerations
This document has no actions for IANA. This document has no actions for IANA.
RSVP Aggregation over MPLS TE tunnels July 2005
10. Acknowledgments 10. Acknowledgments
This document builds on the [RSVP-AGGR], [RSVP-TUN] and [LSP-HIER] This document builds on the [RSVP-AGG], [RSVP-TUN] and [LSP-HIER]
specifications. Also, we would like to thank Tom Phelan, John Drake specifications. Also, we would like to thank Tom Phelan, John Drake,
and Arthi Ayyangar for their input into this document. Arthi Ayyangar, Fred Baker, Subha Dhesikan, Kwok-Ho Chan, Carol
Iturralde and James Gibson for their input into this document.
11. Normative References 11. Normative References
[RFC2119] S. Bradner, Key words for use in RFCs to Indicate [RFC2119] S. Bradner, Key words for use in RFCs to Indicate
Requirement Levels, RFC2119, March 1997. Requirement Levels, RFC2119, March 1997.
[RFC3668] S. Bradner, Intellectual Property Rights in IETF Technology, [RFC3668] S. Bradner, Intellectual Property Rights in IETF Technology,
RFC 3668, February 2004. RFC 3668, February 2004.
[BCP-78], S. Bradner, IETF Rights in Contributions, RFC3978, March [BCP-78], S. Bradner, IETF Rights in Contributions, RFC3978, March
2005. 2005.
[RSVP] Braden et al., Resource ReSerVation Protocol (RSVP) -- Version
1 Functional Specification, RFC 2205, September 1997.
[INT-SERV] Braden, R., Clark, D. and S. Shenker, Integrated Services [INT-SERV] Braden, R., Clark, D. and S. Shenker, Integrated Services
in the Internet Architecture: an Overview, RFC 1633, June 1994. in the Internet Architecture: an Overview, RFC 1633, June 1994.
[GUARANTEED] Shenker et al., Specification of Guaranteed Quality of [GUARANTEED] Shenker et al., Specification of Guaranteed Quality of
Service, RFC2212 Service, RFC2212
[CONTROLLED] Wroclawski, Specification of the Controlled-Load Network [CONTROLLED] Wroclawski, Specification of the Controlled-Load Network
Element Service, RFC2211 Element Service, RFC2211
[DIFFSERV] Blake et al., An Architecture for Differentiated Services, [DIFFSERV] Blake et al., An Architecture for Differentiated Services,
RFC 2475 RFC 2475
[INT-DIFF] A Framework for Integrated Services Operation over [INT-DIFF] A Framework for Integrated Services Operation over
Diffserv Networks, RFC 2998, November 2000. Diffserv Networks, RFC 2998, November 2000.
[RSVP-AGGR] Baker et al, Aggregation of RSVP for IPv4 and IPv6 [RSVP-AGG] Baker et al, Aggregation of RSVP for IPv4 and IPv6
Reservations, RFC 3175, September 2001. Reservations, RFC 3175, September 2001.
RSVP Aggregation over MPLS TE tunnels February 2006
[MPLS-TE] Awduche et al., "Requirements for Traffic Engineering over
MPLS", RFC 2702, September 1999.
[RSVP-TE] Awduche et al, RSVP-TE: Extensions to RSVP for LSP Tunnels, [RSVP-TE] Awduche et al, RSVP-TE: Extensions to RSVP for LSP Tunnels,
RFC 3209, December 2001. RFC 3209, December 2001.
[DSTE-PROTO] Le Faucheur et al, Protocol extensions for support of [DSTE-PROTO] Le Faucheur et al, Protocol extensions for support of
Diff-Serv-aware MPLS Traffic Engineering, RFC 4124, June 2005. Diff-Serv-aware MPLS Traffic Engineering, RFC 4124, June 2005.
[LSP-HIER] Kompella et al, LSP Hierarchy with Generalized MPLS TE, [LSP-HIER] Kompella et al, Label Switched Paths (LSP) Hierarchy with
work in progress Generalized Multi-Protocol Label Switching (GMPLS) Traffic
Engineering (TE), RFC 4206
, October 2005
12. Informative References [SEC-ARCH] Kent and Seo, Security Architecture for the Internet
Protocol, RFC 4301, December 2005
RSVP Aggregation over MPLS TE tunnels July 2005 12. Informative References
[DIFF-MPLS] Le Faucheur et al, MPLS Support of Diff-Serv, RFC3270, [DIFF-MPLS] Le Faucheur et al, MPLS Support of Diff-Serv, RFC3270,
May 2002. May 2002.
[DSTE-REQ] Le Faucheur et al, Requirements for support of Diff-Serv- [DSTE-REQ] Le Faucheur et al, Requirements for support of Diff-Serv-
aware MPLS Traffic Engineering, RFC3564, July 2003. aware MPLS Traffic Engineering, RFC3564, July 2003.
[6PE] De Clercq et al, Connecting IPv6 Islands over IPv4 MPLS using [6PE] De Clercq et al, Connecting IPv6 Islands over IPv4 MPLS using
IPv6 Provider Edge Routers (6PE), work in progress IPv6 Provider Edge Routers (6PE), work in progress
[RSVP-IPSEC] Berger et al, RSVP Extensions for IPSEC Data Flows, RFC [RSVP-IPSEC] Berger et al, RSVP Extensions for IPSEC Data Flows, RFC
2207 2207
[RSVP-AGG-IPSEC] Le Faucheur et al, Generic Aggregate RSVP [RSVP-GEN-AGG] Le Faucheur et al, Generic Aggregate RSVP Reservations,
Reservations, draft-lefaucheur-rsvp-ipsec-01.txt, work in progress draft-lefaucheur-rsvp-ipsec, work in progress
[RSVP-TUN] Terzis et al., RSVP Operation Over IP Tunnels, RFC 2746, [RSVP-TUN] Terzis et al., RSVP Operation Over IP Tunnels, RFC 2746,
January 2000 January 2000
[RSVP-PREEMP] Herzog, Signaled Preemption Priority Policy Element, [RSVP-PREEMP] Herzog, Signaled Preemption Priority Policy Element,
RFC 3181 RFC 3181
[L-RSVP] Manner et al., Localized RSVP, draft-manner-lrsvp-04.txt, [L-RSVP] Manner et al., Localized RSVP, draft-manner-lrsvp-04.txt,
work in progress. work in progress.
[RSVP-PROXY] Gai et al., RSVP Proxy, draft-ietf-rsvp-proxy-03.txt [RSVP-PROXY] Gai et al., RSVP Proxy, draft-ietf-rsvp-proxy-03.txt
(expired), work in progress. (expired), work in progress.
RSVP Aggregation over MPLS TE tunnels February 2006
[RSVP-APPID] Bernet et al., Identity Representation for RSVP, RFC [RSVP-APPID] Bernet et al., Identity Representation for RSVP, RFC
3182. 3182.
[AUTOMESH] Vasseur and Leroux, Routing extensions for discovery of [AUTOMESH] Vasseur and Leroux, Routing extensions for discovery of
Multiprotocol (MPLS) Label Switch Router (LSR) Traffic Engineering Multiprotocol (MPLS) Label Switch Router (LSR) Traffic Engineering
(TE) mesh membership, draft-vasseur-ccamp-automesh-00.txt, work in (TE) mesh membership, draft-vasseur-ccamp-automesh-00.txt, work in
progress. progress.
[SIP-RSVP] Camarillo, Integration of Resource Management and Session [SIP-RSVP] Camarillo, Integration of Resource Management and Session
Initiation Protocol (SIP), RFC 3312 Initiation Protocol (SIP), RFC 3312
skipping to change at page 20, line 5 skipping to change at page 23, line 28
13. Authors Address: 13. Authors Address:
Francois Le Faucheur Francois Le Faucheur
Cisco Systems, Inc. Cisco Systems, Inc.
Village d'Entreprise Green Side - Batiment T3 Village d'Entreprise Green Side - Batiment T3
400, Avenue de Roumanille 400, Avenue de Roumanille
06410 Biot Sophia-Antipolis 06410 Biot Sophia-Antipolis
France France
Email: flefauch@cisco.com Email: flefauch@cisco.com
RSVP Aggregation over MPLS TE tunnels July 2005
Michael DiBiasio Michael DiBiasio
Cisco Systems, Inc. Cisco Systems, Inc.
300 Beaver Brook Road 300 Beaver Brook Road
Boxborough, MA 01719 Boxborough, MA 01719
USA USA
Email: dibiasio@cisco.com Email: dibiasio@cisco.com
Bruce Davie Bruce Davie
Cisco Systems, Inc. Cisco Systems, Inc.
300 Beaver Brook Road 300 Beaver Brook Road
skipping to change at page 20, line 30 skipping to change at page 24, line 4
Christou Christou Christou Christou
Booz Allen Hamilton Booz Allen Hamilton
8283 Greensboro Drive 8283 Greensboro Drive
McLean, VA 22102 McLean, VA 22102
USA USA
Email: christou_chris@bah.com Email: christou_chris@bah.com
Michael Davenport Michael Davenport
Booz Allen Hamilton Booz Allen Hamilton
RSVP Aggregation over MPLS TE tunnels February 2006
8283 Greensboro Drive 8283 Greensboro Drive
McLean, VA 22102 McLean, VA 22102
USA USA
Email: davenport_michael@bah.com Email: davenport_michael@bah.com
Jerry Ash Jerry Ash
AT&T AT&T
200 Laurel Avenue 200 Laurel Avenue
Middletown, NJ 07748, USA Middletown, NJ 07748, USA
USA USA
Email: gash@att.com Email: gash@att.com
Bur Goode Bur Goode
AT&T AT&T
32 Old Orchard Drive 32 Old Orchard Drive
Weston, CT 06883 Weston, CT 06883
USA USA
Email: bgoode@att.com Email: bgoode@att.com
RSVP Aggregation over MPLS TE tunnels July 2005
14. IPR Statements 14. IPR Statements
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79. found in BCP 78 and BCP 79.
skipping to change at page 21, line 31 skipping to change at page 25, line 5
such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr. http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. this standard.
Please address the information to the IETF at ietf-ipr@ietf.org. Please address the information to the IETF at ietf-ipr@ietf.org.
RSVP Aggregation over MPLS TE tunnels February 2006
15. Disclaimer of Validity 15. Disclaimer of Validity
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
16. Copyright Notice 16. Copyright Notice
Copyright (C) The Internet Society (2005). This document is subject Copyright (C) The Internet Society (2005). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights. except as set forth therein, the authors retain all their rights.
Appendix A - Example Usage of RSVP Aggregation over DSTE Tunnels for Appendix A - Example Usage of RSVP Aggregation over DSTE Tunnels for
VoIP Call Admission Control (CAC) VoIP Call Admission Control (CAC)
RSVP Aggregation over MPLS TE tunnels July 2005
This Appendix presents an example scenario where the mechanisms This Appendix presents an example scenario where the mechanisms
described in this document are used, in combination with other described in this document are used, in combination with other
mechanisms specified by the IETF, to achieve Call Admission Control mechanisms specified by the IETF, to achieve Call Admission Control
of Voice over IP (VoIP) traffic over the packet core. (CAC) of Voice over IP (VoIP) traffic over the packet core.
The information is that Appendix is purely informational and The information is that Appendix is purely informational and
illustrative. illustrative.
Consider the scenario depicted in Figure A1. VoIP Gateways GW1 and Consider the scenario depicted in Figure A1. VoIP Gateways GW1 and
GW2 are both signaling and media gateways. They are connected to an GW2 are both signaling and media gateways. They are connected to an
MPLS network via edge routers PE1 and PE2, respectively. In each MPLS network via edge routers PE1 and PE2, respectively. In each
direction, a DSTE tunnel passes from the head-end edge router, direction, a DSTE tunnel passes from the head-end edge router,
through core network P routers, to the tail-end edge router. GW1 and through core network P routers, to the tail-end edge router. GW1 and
GW2 are RSVP-enabled. The RSVP reservations established by GW1 and GW2 are RSVP-enabled. The RSVP reservations established by GW1 and
skipping to change at page 22, line 34 skipping to change at page 26, line 4
reservations going from GW2 to GW2, PE2 serves as the reservations going from GW2 to GW2, PE2 serves as the
aggregator/head-end and PE1 serves as the de-aggregator/tail-end. aggregator/head-end and PE1 serves as the de-aggregator/tail-end.
To determine whether there is sufficient bandwidth in the MPLS core To determine whether there is sufficient bandwidth in the MPLS core
to complete a connection, the originating and destination GWs each to complete a connection, the originating and destination GWs each
send for each connection a Resource Reservation Protocol (RSVP) send for each connection a Resource Reservation Protocol (RSVP)
bandwidth request to the network PE router to which it is connected. bandwidth request to the network PE router to which it is connected.
The bandwidth request takes into account VoIP header compression, The bandwidth request takes into account VoIP header compression,
where applicable. As part of its Aggregator role, the PE router where applicable. As part of its Aggregator role, the PE router
effectively performs admission control of the bandwidth request effectively performs admission control of the bandwidth request
RSVP Aggregation over MPLS TE tunnels February 2006
generated by the GW onto the resources of the corresponding DS-TE generated by the GW onto the resources of the corresponding DS-TE
tunnel. tunnel.
In this example, in addition to behaving as Aggregator/Deaggregator, In this example, in addition to behaving as Aggregator/Deaggregator,
PE1 and PE2 behave as RSVP proxy. So when a PE receives a Path PE1 and PE2 behave as RSVP proxy. So when a PE receives a Path
message from a GW, it does not propagate the Path message any further. message from a GW, it does not propagate the Path message any further.
Rather, the PE performs admission control of the bandwidth signaled Rather, the PE performs admission control of the bandwidth signaled
in the Path message over the DSTE tunnel towards the destination. in the Path message over the DSTE tunnel towards the destination.
Assuming there is enough bandwidth available on that tunnel, the PE Assuming there is enough bandwidth available on that tunnel, the PE
adjusts its book-keeping of remaining available bandwidth on the adjusts its book-keeping of remaining available bandwidth on the
tunnel and generates a Resv message back towards the GW to confirm tunnel and generates a Resv message back towards the GW to confirm
resources have been reserved over the DSTE tunnel. resources have been reserved over the DSTE tunnel.
RSVP Aggregation over MPLS TE tunnels July 2005
,-. ,-. ,-. ,-.
_.---' `---' `-+ _.---' `---' `-+
,-'' +------------+ : ,-'' +------------+ :
( | | `. ( | | `.
\ ,' CCA `. : \ ,' CCA `. :
\ ,' | | `. ; \ ,' | | `. ;
;' +------------+ `._ ;' +------------+ `._
,'+ ; `. ,'+ ; `.
,' -+ Application Layer' `. ,' -+ Application Layer' `.
SIP,' `---+ | ; `.SIP SIP,' `---+ | ; `.SIP
skipping to change at page 23, line 42 skipping to change at page 27, line 4
`--. ,.__,| | IP/MPLS Network / '---'- ----' `--. ,.__,| | IP/MPLS Network / '---'- ----'
'`' '' ' .._,,'`.__ _/ '---' | '`' '' ' .._,,'`.__ _/ '---' |
| '`''' | | '`''' |
C1 C2 C1 C2
Figure A1. Integration of SIP Resource Management, DSTE Figure A1. Integration of SIP Resource Management, DSTE
and RSVP Aggregation and RSVP Aggregation
[SIP-RSVP] discusses how network quality of service can be made a [SIP-RSVP] discusses how network quality of service can be made a
precondition for establishment of sessions initiated by the Session precondition for establishment of sessions initiated by the Session
RSVP Aggregation over MPLS TE tunnels February 2006
Initiation Protocol (SIP). These preconditions require that the Initiation Protocol (SIP). These preconditions require that the
participant reserve network resources before continuing with the participant reserve network resources before continuing with the
session. The reservation of network resources are performed through a session. The reservation of network resources are performed through a
signaling protocol such as RSVP. signaling protocol such as RSVP.
Our example environment relies of [SIP-RSVP] to synchronize RSVP Our example environment relies of [SIP-RSVP] to synchronize RSVP
bandwidth reservations with SIP. For example, the RSVP bandwidth bandwidth reservations with SIP. For example, the RSVP bandwidth
requests may be integrated into the call setup flow as follows (See requests may be integrated into the call setup flow as follows (See
call setup flow diagram in Figure A2): call setup flow diagram in Figure A2):
- Caller C1 initiates a call by sending a SIP INVITE to VoIP - Caller C1 initiates a call by sending a SIP INVITE to VoIP
gateway GW1, which passes the INVITE along to the call control gateway GW1, which passes the INVITE along to the call control
RSVP Aggregation over MPLS TE tunnels July 2005
agent (CCA). The INVITE message may contain a list of codecs agent (CCA). The INVITE message may contain a list of codecs
that the calling phone can support. that the calling phone can support.
- VoIP gateway GW2, chooses a compatible codec from the list and - VoIP gateway GW2, chooses a compatible codec from the list and
responds with a SIP message 183 Session Progress. responds with a SIP message 183 Session Progress.
- When GW1 receives the SIP response message and learns the codec - When GW1 receives the SIP response message and learns the codec
to be used, it knows how much bandwidth is required for the to be used, it knows how much bandwidth is required for the
call. call.
skipping to change at page 25, line 5 skipping to change at page 28, line 5
destination phone, which responds with SIP message 180 RINGING. destination phone, which responds with SIP message 180 RINGING.
- When (and if) the called party answers, the destination phone - When (and if) the called party answers, the destination phone
responds with another SIP 200 OK which completes the connection responds with another SIP 200 OK which completes the connection
and tells the calling party that there is now reserved and tells the calling party that there is now reserved
bandwidth in both directions so that conversation can begin. bandwidth in both directions so that conversation can begin.
- RTP media streams in both directions pass through the DSTE - RTP media streams in both directions pass through the DSTE
tunnels as they traverse the MPLS network. tunnels as they traverse the MPLS network.
RSVP Aggregation over MPLS TE tunnels July 2005 RSVP Aggregation over MPLS TE tunnels February 2006
IP-Phone/ IP-Phone/ IP-Phone/ IP-Phone/
TA-C1 GW1 PE1 CCA PE2 GW2 TA-C2 TA-C1 GW1 PE1 CCA PE2 GW2 TA-C2
| INVITE|(SDP1) | INVITE | INVITE | | | | INVITE|(SDP1) | INVITE | INVITE | | |
|---------->|-------|---------->|------------|------->| | |---------->|-------|---------->|------------|------->| |
| 100|TRYING | | | | | | 100|TRYING | | | | |
|<----------|-------|-----------| | | | |<----------|-------|-----------| | | |
| 183|(SDP2) | | | | | | 183|(SDP2) | | | | |
|<----------|-------|-----------|------------|--------| | |<----------|-------|-----------|------------|--------| |
| | PATH | | | PATH | | | | PATH | | | PATH | |
skipping to change at page 26, line 5 skipping to change at page 29, line 5
a) the PE and GW collaborate to determine whether there is enough a) the PE and GW collaborate to determine whether there is enough
bandwidth on the tunnel between the calling and called GWs to bandwidth on the tunnel between the calling and called GWs to
accommodate the connection, accommodate the connection,
b) the corresponding accept/reject decision is communicated to the b) the corresponding accept/reject decision is communicated to the
GWs on a connection-by-connection basis, and GWs on a connection-by-connection basis, and
c) the PE can optimize network resources by dynamically adjusting c) the PE can optimize network resources by dynamically adjusting
the bandwidth of each tunnel according to the load over that tunnel. the bandwidth of each tunnel according to the load over that tunnel.
For example, if a tunnel is operating near capacity, the network may For example, if a tunnel is operating near capacity, the network may
dynamically adjust the tunnel size within a set of parameters. dynamically adjust the tunnel size within a set of parameters.
RSVP Aggregation over MPLS TE tunnels July 2005 RSVP Aggregation over MPLS TE tunnels February 2006
We note that admission Control of voice calls over the core network We note that admission Control of voice calls over the core network
capacity is achieved in a hierarchical manner whereby: capacity is achieved in a hierarchical manner whereby:
- DSTE tunnels are subject to CAC over the resources of the MPLS - DSTE tunnels are subject to Admission Control over the
TE core resources of the MPLS TE core
- Voice calls are subject to CAC over the DSTE tunnel bandwidth - Voice calls are subject to CAC over the DSTE tunnel bandwidth
This hierarchy is a key element in the scalability of this CAC This hierarchy is a key element in the scalability of this CAC
solution for voice calls over an MPLS Core. solution for voice calls over an MPLS Core.
It is also possible for the GWs to use aggregate RSVP reservations It is also possible for the GWs to use aggregate RSVP reservations
themselves instead of per-call RSVP reservations. For example, themselves instead of per-call RSVP reservations. For example,
instead of setting one reservation for each call GW1 has in place instead of setting one reservation for each call GW1 has in place
towards GW2, GW1 may establish one (or a small number of) aggregate towards GW2, GW1 may establish one (or a small number of) aggregate
reservations as defined in [RSVP-AGGR] which is used for all (or a reservations as defined in [RSVP-AGG] which is used for all (or a
subset of all) the calls towards GW2. This effectively provides an subset of all) the calls towards GW2. This effectively provides an
additional level of hierarchy whereby: additional level of hierarchy whereby:
- -
DSTE tunnels are subject to CAC over the resources of the MPLS DSTE tunnels are subject to Admission Control over the
TE core resources of the MPLS TE core
- Aggregate RSVP reservations from GW to GW are subject to CAC - Aggregate RSVP reservations (for the calls from one GW to
over the DSTE tunnels (as per the "RSVP Aggregation over TE another GW) are subject to Admission Control over the DSTE
Tunnels" procedures defined in this document) tunnels (as per the "RSVP Aggregation over TE Tunnels"
procedures defined in this document)
- Voice calls are subject to CAC by the GW over the aggregate - Voice calls are subject to CAC by the GW over the aggregate
reservation towards the appropriate destination GW. reservation towards the appropriate destination GW.
This pushes even further the scalability limits of this voice CAC This pushes even further the scalability limits of this voice CAC
architecture. architecture.
 End of changes. 102 change blocks. 
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