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rfc:rfc5824

Internet Engineering Task Force (IETF) K. Kumaki, Ed. Request for Comments: 5824 KDDI Corporation Category: Informational R. Zhang ISSN: 2070-1721 BT

                                                             Y. Kamite
                                        NTT Communications Corporation
                                                            April 2010
                    Requirements for Supporting
           Customer Resource ReSerVation Protocol (RSVP)
   and RSVP Traffic Engineering (RSVP-TE) over a BGP/MPLS IP-VPN

Abstract

 Today, customers expect to run triple-play services through BGP/MPLS
 IP-VPNs.  Some service providers will deploy services that request
 Quality of Service (QoS) guarantees from a local Customer Edge (CE)
 to a remote CE across the network.  As a result, the application
 (e.g., voice, video, bandwidth-guaranteed data pipe, etc.)
 requirements for an end-to-end QoS and reserving an adequate
 bandwidth continue to increase.
 Service providers can use both an MPLS and an MPLS Traffic
 Engineering (MPLS-TE) Label Switched Path (LSP) to meet their service
 objectives.  This document describes service-provider requirements
 for supporting a customer Resource ReSerVation Protocol (RSVP) and
 RSVP-TE over a BGP/MPLS IP-VPN.

Status of This Memo

 This document is not an Internet Standards Track specification; it is
 published for informational purposes.
 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/rfc5824.

Kumaki, et al. Informational [Page 1] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

Copyright Notice

 Copyright (c) 2010 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.
 This document may contain material from IETF Documents or IETF
 Contributions published or made publicly available before November
 10, 2008.  The person(s) controlling the copyright in some of this
 material may not have granted the IETF Trust the right to allow
 modifications of such material outside the IETF Standards Process.
 Without obtaining an adequate license from the person(s) controlling
 the copyright in such materials, this document may not be modified
 outside the IETF Standards Process, and derivative works of it may
 not be created outside the IETF Standards Process, except to format
 it for publication as an RFC or to translate it into languages other
 than English.

Kumaki, et al. Informational [Page 2] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

Table of Contents

 1. Introduction ....................................................4
 2. Requirements Language ...........................................4
 3. Terminology .....................................................5
 4. Problem Statement ...............................................5
 5. Application Scenarios ...........................................7
    5.1. Scenario I: Fast Recovery over BGP/MPLS IP-VPNs ............8
    5.2. Scenario II: Strict C-TE LSP QoS Guarantees ................8
    5.3. Scenario III: Load Balance of CE-to-CE Traffic .............9
    5.4. Scenario IV: RSVP Aggregation over MPLS-TE Tunnels ........11
    5.5. Scenario V: RSVP over Non-TE LSPs .........................12
    5.6. Scenario VI: RSVP-TE over Non-TE LSPs .....................13
 6. Detailed Requirements for C-TE LSP Model .......................14
    6.1. Selective P-TE LSPs .......................................14
    6.2. Graceful Restart Support for C-TE LSPs ....................14
    6.3. Rerouting Support for C-TE LSPs ...........................15
    6.4. FRR Support for C-TE LSPs .................................15
    6.5. Admission Control Support on P-TE LSP Head-Ends ...........15
    6.6. Admission Control Support for C-TE LSPs in
         LDP-Based Core Networks ...................................16
    6.7. Policy Control Support for C-TE LSPs ......................16
    6.8. PCE Features Support for C-TE LSPs ........................16
    6.9. Diversely Routed C-TE LSP Support .........................16
    6.10. Optimal Path Support for C-TE LSPs .......................17
    6.11. Reoptimization Support for C-TE LSPs .....................17
    6.12. DS-TE Support for C-TE LSPs ..............................17
 7. Detailed Requirements for C-RSVP Path Model ....................18
    7.1. Admission Control between PE-CE for C-RSVP Paths ..........18
    7.2. Aggregation of C-RSVP Paths by P-TE LSPs ..................18
    7.3. Non-TE LSP Support for C-RSVP Paths .......................18
    7.4. Transparency of C-RSVP Paths ..............................18
 8. Commonly Detailed Requirements for Two Models ..................18
    8.1. CE-PE Routing .............................................18
    8.2. Complexity and Risks ......................................19
    8.3. Backward Compatibility ....................................19
    8.4. Scalability Considerations ................................19
    8.5. Performance Considerations ................................19
    8.6. Management Considerations .................................20
 9. Security Considerations ........................................20
 10. References ....................................................21
    10.1. Normative References .....................................21
    10.2. Informative References ...................................22
 Acknowledgments....................................................23
 Appendix A. Reference Model........................................24
    A.1 End-to-End C-RSVP Path Model................................24
    A.2 End-to-End C-TE LSP Model...................................25

Kumaki, et al. Informational [Page 3] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

1. Introduction

 Some service providers want to build a service that guarantees
 Quality of Service (QoS) and a bandwidth from a local Customer Edge
 (CE) to a remote CE through the network.  A CE includes the network
 client equipment owned and operated by the service provider.
 However, the CE may not be part of the MPLS provider network.
 Today, customers expect to run triple-play services such as Internet
 access, telephone, and television through BGP/MPLS IP-VPNs [RFC4364].
 As these services evolve, the requirements for an end-to-end QoS to
 meet the application requirements also continue to grow.  Depending
 on the application (e.g., voice, video, bandwidth-guaranteed data
 pipe, etc.), a native IP using an RSVP and/or an end-to-end
 constrained MPLS Traffic Engineering (MPLS-TE) Label Switched Path
 (LSP) may be required.  The RSVP path may be used to provide QoS
 guarantees and reserve an adequate bandwidth for the data.  An end-
 to-end MPLS-TE LSP may also be used to guarantee a bandwidth, and
 provide extended functionality like MPLS fast reroute (FRR) [RFC4090]
 for maintaining the service continuity around node and link,
 including the CE-PE link, failures.  It should be noted that an RSVP
 session between two CEs may also be mapped and tunneled into an MPLS-
 TE LSP across an MPLS provider network.
 A number of advantages exist for deploying the model previously
 mentioned.  The first is that customers can use these network
 services while being able to use both private addresses and global
 addresses.  The second advantage is that the traffic is tunneled
 through the service-provider backbone so that customer traffic and
 route confidentiality are maintained.
 This document defines a reference model, example application
 scenarios, and detailed requirements for a solution supporting a
 customer RSVP and RSVP-TE over a BGP/MPLS IP-VPN.
 A specification for a solution is out of scope in this document.

2. Requirements Language

 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].

Kumaki, et al. Informational [Page 4] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

3. Terminology

 This document uses the BGP/MPLS IP-VPN terminology defined in
 [RFC4364] and also uses Path Computation Element (PCE) terms defined
 in [RFC4655].
 TE LSP: Traffic Engineering Label Switched Path
 MPLS-TE LSP: Multiprotocol Label Switching TE LSP
 C-RSVP path: Customer RSVP path: a native RSVP path with the
              bandwidth reservation of X for customers
 C-TE LSP: Customer Traffic Engineering Label Switched Path: an end-
           to-end MPLS-TE LSP for customers
 P-TE LSP: Provider Traffic Engineering Label Switched Path: a
           transport TE LSP between two Provider Edges (PEs)
 LSR: a Label Switched Router
 Head-end LSR: an ingress LSR
 Tail-end LSR: an egress LSR

4. Problem Statement

 Service providers want to deliver triple-play services with QoS
 guarantees to their customers.  Various techniques are available to
 achieve this.  Some service providers will wish to offer advanced
 services using an RSVP signaling for native IP flows (C-RSVP) or an
 RSVP-TE signaling for Customer TE LSPs (C-TE LSPs) over BGP/MPLS
 IP-VPNs.
 The following examples outline each method:
 A C-RSVP path with the bandwidth reservation of X can be used to
 transport voice traffic.  In order to achieve recovery in under 50 ms
 during link, node, and Shared Risk Link Group (SRLG) failures, and to
 provide strict QoS guarantees, a C-TE LSP with bandwidth X between
 data centers or customer sites can be used to carry voice and video
 traffic.  Thus, service providers or customers can choose a C-RSVP
 path or a C-TE LSP to meet their requirements.
 When service providers offer a C-RSVP path between hosts or CEs over
 BGP/MPLS IP-VPNs, the CE/host requests an end-to-end C-RSVP path with
 the bandwidth reservation of X to the remote CE/host.  However, if a
 C-RSVP signaling is to send within a VPN, the service-provider

Kumaki, et al. Informational [Page 5] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

 network will face scalability issues because routers need to retain
 the RSVP state per a customer.  Therefore, in order to solve
 scalability issues, multiple C-RSVP reservations can be aggregated at
 a PE, where a P-TE LSP head-end can perform admission control using
 the aggregated C-RSVP reservations.  The method that is described in
 [RFC4804] can be considered as a useful approach.  In this case, a
 reservation request from within the context of a Virtual Routing and
 Forwarding (VRF) instance can get aggregated onto a P-TE LSP.  The
 P-TE LSP can be pre-established, resized based on the request, or
 triggered by the request.  Service providers, however, cannot provide
 a C-RSVP path over the VRF instance as defined in [RFC4364].  The
 current BGP/MPLS IP-VPN architecture also does not support an RSVP
 instance running in the context of a VRF to process RSVP messages and
 integrated services (int-serv) ([RFC1633], [RFC2210]).  One solution
 is described in [RSVP-L3VPN].
 If service providers offer a C-TE LSP from a CE to a CE over the
 BGP/MPLS IP-VPN, they require that an MPLS-TE LSP from a local CE to
 a remote CE be established.  However, if a C-TE LSP signaling is to
 send within the VPN, the service-provider network may face the
 following scalability issues:
  1. A C-TE LSP can be aggregated by a P-TE LSP at a PE (i.e.,

hierarchical LSPs). In this case, only a PE maintains the state of

   customer RSVP sessions.
  1. A C-TE LSP cannot be aggregated by a P-TE LSP at a PE, depending on

some policies (i.e., continuous LSPs). In this case, both Ps and

   PEs maintain the state of customer RSVP sessions.
  1. A C-TE LSP can be aggregated by the non-TE LSP (i.e., LDP).

In this case, only a PE maintains the state of customer RSVP-TE

   sessions.  Note that it is assumed that there is always enough
   bandwidth available in the service-provider core network.
 Furthermore, if service providers provide the C-TE LSP over the
 BGP/MPLS IP-VPN, they currently cannot provide it over the VRF
 instance as defined in [RFC4364].  Specifically, the current BGP/MPLS
 IP-VPN architecture does not support the RSVP-TE instance running in
 the context of a VRF to process RSVP messages and trigger the
 establishment of the C-TE LSP over the service-provider core network.
 If every C-TE LSP is to trigger the establishment or resizing of a
 P-TE LSP, the service-provider network will also face scalability
 issues that arise from maintaining a large number of P-TE LSPs and/or

Kumaki, et al. Informational [Page 6] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

 the dynamic signaling of these P-TE LSPs.  Section 8.4 of this
 document, "Scalability Considerations", provides detailed scalability
 requirements.
 Two different models have been described above.  The differences
 between C-RSVP paths and C-TE LSPs are as follows:
  1. C-RSVP path model: data packets among CEs are forwarded by "native

IP packets" (i.e., not labeled packets).

  1. C-TE LSP model: data packets among CEs are forwarded by "labeled IP

packets".

 Depending on the service level and the need to meet specific
 requirements, service providers should be able to choose P-TE LSPs or
 non-TE LSPs in the backbone network.  The selection may be dependent
 on the service provider's policy and the node's capability to support
 the mechanisms described.
 The items listed below are selectively required to support C-RSVP
 paths and C-TE LSPs over BGP/MPLS IP-VPNs based on the service level.
 For example, some service providers need all of the following items
 to provide a service, and some service providers need only some of
 them to provide the service.  It depends on the service level and
 policy of service providers.  Detailed requirements are described in
 Sections 6, 7, and 8.
  1. C-RSVP path QoS guarantees.
  1. Fast recovery over the BGP/MPLS IP-VPN to protect traffic for the

C-TE LSP against CE-PE link failure and PE node failure.

  1. Strict C-TE LSP bandwidth and QoS guarantees.
  1. Resource optimization for C-RSVP paths and C-TE LSPs.
  1. Scalability for C-RSVP paths and C-TE LSPs.

5. Application Scenarios

 The following sections present a few application scenarios for C-RSVP
 paths and C-TE LSPs in BGP/MPLS IP-VPN environments.  Appendix A,
 "Reference Model", describes a C-RSVP path, a C-TE LSP, and a
 P-TE LSP.
 In all scenarios, it is the responsibility of the service provider to
 ensure that enough bandwidth is available to meet the customers'
 application requirements.

Kumaki, et al. Informational [Page 7] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

5.1. Scenario I: Fast Recovery over BGP/MPLS IP-VPNs

 In this scenario, as shown in Figure 1, a customer uses a VoIP
 application between its sites (i.e., between CE1 and CE2).  H0 and H1
 represent voice equipment.
 In this case, the customer establishes C-TE LSP1 as a primary path
 and C-TE LSP2 as a backup path.  If the link between PE1 and CE1 or
 the node of PE1 fails, C-TE LSP1 needs C-TE LSP2 as a path
 protection.
 Generally speaking, C-RSVP paths are used by customers, and P-TE LSPs
 are used by service providers.
                              C-TE LSP1
           <---------------------------------------------->
                              P-TE LSP1
                    <--------------------------->
 .............                                         .............
 . ---   --- .     ---      ---       ---      ---     . ---   --- .
 .|H0 | |CE1|-----|PE1|----|P1 |-----|P2 |----|PE2|-----|CE2| |H1 |.
 . ---   --- .     ---      ---       ---      ---     . ---   --- .
 .........|...     ---      ---       ---      ---     ...|.........
          +-------|PE3|----|P3 |-----|P4 |----|PE4|-------+
                   ---      ---       ---      ---
                    <--------------------------->
                              P-TE LSP2
           <---------------------------------------------->
                              C-TE LSP2
 <--customer-->    <--------BGP/MPLS IP-VPN------->    <--customer->
    network                                               network
                         Figure 1.  Scenario I

5.2. Scenario II: Strict C-TE LSP QoS Guarantees

 In this scenario, as shown in Figure 2, service provider B (SP B)
 transports voice and video traffic between its sites (i.e., between
 CE1 and CE2).  In this case, service provider B establishes C-TE LSP1
 with preemption priority 0 and 100-Mbps bandwidth for the voice
 traffic, and C-TE LSP2 with preemption priority 1 and 200-Mbps
 bandwidth for the unicast video traffic.  On the other hand, service
 provider A (SP A) also pre-establishes P-TE LSP1 with preemption
 priority 0 and 1-Gbps bandwidth for the voice traffic, and P-TE LSP2
 with preemption priority 1 and 2-Gbps bandwidth for the video

Kumaki, et al. Informational [Page 8] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

 traffic.  In this scenario, P-TE LSP1 and P-TE LSP2 should support
 Diffserv-aware MPLS Traffic Engineering (DS-TE) [RFC4124].
 PE1 and PE3 should choose an appropriate P-TE LSP based on the
 preemption priority.  In this case, C-TE LSP1 must be associated with
 P-TE LSP1 at PE1, and C-TE LSP2 must be associated with P-TE LSP2 at
 PE3.
 Furthermore, PE1 and PE3 head-ends should control the bandwidth of
 C-TE LSPs.  In this case, PE1 and PE3 can choose C-TE LSPs by the
 amount of maximum available bandwidth for each P-TE LSP,
 respectively.
                              C-TE LSP1
           <---------------------------------------------->
                              P-TE LSP1
                    <--------------------------->
 .............                                         .............
 . ---   --- .     ---      ---       ---      ---     . ---   --- .
 .|CE0| |CE1|-----|PE1|----|P1 |-----|P2 |----|PE2|-----|CE2| |CE3|.
 . ---   --- .     ---      ---       ---      ---     . ---   --- .
 .........|...     ---      ---       ---      ---     ...|.........
          +-------|PE3|----|P3 |-----|P4 |----|PE4|-------+
                   ---      ---       ---      ---
                    <--------------------------->
                              P-TE LSP2
           <---------------------------------------------->
                              C-TE LSP2
  <---SP B---->    <--------BGP/MPLS IP-VPN------->     <---SP B--->
     network                 SP A network                 network
                        Figure 2.  Scenario II
 It's possible that the customer and the service provider have
 differing preemption priorities.  In this case, the PE policy will
 override the customers.  In the case where the service provider does
 not support preemption priorities, then such priorities should be
 ignored.

5.3. Scenario III: Load Balance of CE-to-CE Traffic

 In this scenario, as shown in Figure 3, service provider C (SP C)
 uses voice and video traffic between its sites (i.e., between CE0 and
 CE5/CE7, between CE2 and CE5/CE7, between CE5 and CE0/CE2, and
 between CE7 and CE0/CE2).  H0 and H1 represent voice and video
 equipment.  In this case, service provider C establishes C-TE LSP1,

Kumaki, et al. Informational [Page 9] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

 C-TE LSP3, C-TE LSP5, and C-TE LSP7 with preemption priority 0 and
 100-Mbps bandwidth for the voice traffic, and establishes C-TE LSP2,
 C-TE LSP4, C-TE LSP6, and C-TE LSP8 with preemption priority 1 and
 200-Mbps bandwidth for the video traffic.  On the other hand, service
 provider A also pre-establishes P-TE LSP1 and P-TE LSP3 with
 preemption priority 0 and 1-Gbps bandwidth for the voice traffic, and
 P-TE LSP2 and P-TE LSP4 with preemption priority 1 and 2-Gbps
 bandwidth for the video traffic.  In this scenario, P-TE LSP1,
 P-TE LSP2, P-TE LSP3, and P-TE LSP4 should support DS-TE [RFC4124].
 All PEs should choose an appropriate P-TE LSP based on the preemption
 priority.  To minimize the traffic disruption due to a single network
 failure, diversely routed C-TE LSPs are established.  In this case,
 the FRR [RFC4090] is not necessarily required.
 Also, unconstrained TE LSPs (i.e., C-TE LSPs/P-TE LSPs with
 0 bandwidth) [RFC5330] are applicable to this scenario.
 Furthermore, the load balancing for any communication between H0 and
 H1 can be done by setting up full-mesh C-TE LSPs between CE0/CE2 and
 CE5/CE7.

Kumaki, et al. Informational [Page 10] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

           C-TE LSP1(P=0),2(P=1) (CE0->CE1->...->CE4->CE5)
                                 (CE0<-CE1<-...<-CE4<-CE5)
          <---------------------------------------------->
           C-TE LSP3(P=0),4(P=1) (CE2->CE1->...->CE4->CE7)
                                 (CE2<-CE1<-...<-CE4<-CE7)
          <---------------------------------------------->
                           P-TE LSP1 (p=0)
                       <-------------------->
                           P-TE LSP2 (p=1)
                       <-------------------->
 ..................                             ..................
 .      ---   --- .  ---    ---     ---    ---  . ---   ---      .
 .     |CE0|-|CE1|--|PE1|--|P1 |---|P2 |--|PE2|--|CE4|-|CE5|     .
 . --- /---   --- .  ---     ---    ---    ---  . ---   ---\ --- .
 .|H0 |     +     .              +              .     +     |H1 |.
 . --- \---   --- .  ---    ---     ---    ---  . ---   ---/ --- .
 .     |CE2|-|CE3|--|PE3|--|P3 |---|P4 |--|PE4|--|CE6|-|CE7|     .
 .      ---   --- .  ---    ---     ---    ---  . ---   ---      .
 ..................                             ..................
                       <-------------------->
                           P-TE LSP3 (p=0)
                       <-------------------->
                           P-TE LSP4 (p=1)
          <---------------------------------------------->
           C-TE LSP5(P=0),6(P=1)  (CE0->CE3->...->CE6->CE5)
                                  (CE0<-CE3<-...<-CE6<-CE5)
          <---------------------------------------------->
           C-TE LSP7(P=0),8(P=1)  (CE2->CE3->...->CE6->CE7)
                                  (CE2<-CE3<-...<-CE6<-CE7)
  <-----SP C----->   <----BGP/MPLS IP-VPN---->   <-----SP C----->
       network               SP A network             network
                        Figure 3.  Scenario III

5.4. Scenario IV: RSVP Aggregation over MPLS-TE Tunnels

 In this scenario, as shown in Figure 4, the customer has two hosts
 connecting to CE1 and CE2, respectively.  CE1 and CE2 are connected
 to PE1 and PE2, respectively, within a VRF instance belonging to the
 same VPN.  The requesting host (H1) may request from H2 an RSVP path
 with the bandwidth reservation of X.  This reservation request from
 within the context of VRF will get aggregated onto a pre-established
 P-TE/DS-TE LSP based upon procedures similar to [RFC4804].  As in the
 case of [RFC4804], there may be multiple P-TE LSPs belonging to
 different DS-TE class-types.  Local policies can be implemented to

Kumaki, et al. Informational [Page 11] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

 map the incoming RSVP path request from H1 to the P-TE LSP with the
 appropriate class-type.  Please note that the end-to-end (e2e) RSVP
 path request may also be initiated by the CE devices themselves.
                              C-RSVP path
      <----------------------------------------------------->
                              P-TE LSP
                   <--------------------------->
  .............                                     .............
  . ---   --- .   ---      ---       ---      ---   . ---   --- .
  .|H1 | |CE1|---|PE1|----|P1 |-----|P2 |----|PE2|---|CE2| |H2 |.
  . ---   --- .   ---      ---       ---      ---   . ---   --- .
  .............                                     .............
                 ^                               ^
                 |                               |
             VRF instance                    VRF instance
   <-customer->   <--------BGP/MPLS IP-VPN------->   <-customer->
     network                                           network
                        Figure 4.  Scenario IV

5.5. Scenario V: RSVP over Non-TE LSPs

 In this scenario, as shown in Figure 5, a customer has two hosts
 connecting to CE1 and CE2, respectively.  CE1 and CE2 are connected
 to PE1 and PE2, respectively, within a VRF instance belonging to the
 same VPN.  The requesting host (H1) may request from H2 an RSVP path
 with the bandwidth reservation of X.  In this case, a non-TE LSP
 (i.e., LDP, etc.) is provided between PEs and has LDP, which supports
 MPLS Diffserv [RFC3270].
 Note that this only provides Diffserv, and not the bandwidth
 reservation as is done with RSVP-TE.
 Local policies can be implemented to map the customer's reserved flow
 to the LSP with the appropriate Traffic Class [RFC5462] at PE1.

Kumaki, et al. Informational [Page 12] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

                             C-RSVP path
            <------------------------------------------>
                             Non-TE LSP
                   <--------------------------->
  .............                                     .............
  . ---   --- .   ---      ---       ---      ---   . ---   --- .
  .|H1 | |CE1|---|PE1|----|P1 |-----|P2 |----|PE2|---|CE2| |H2 |.
  . ---   --- .   ---      ---       ---      ---   . ---   --- .
  .............                                     .............
                 ^                               ^
                 |                               |
             VRF instance                    VRF instance
   <-customer->   <-------BGP/MPLS IP-VPN------->   <-customer->
     network                                          network
                         Figure 5.  Scenario V

5.6. Scenario VI: RSVP-TE over Non-TE LSPs

 In this scenario, as shown in Figure 6, a customer uses a VoIP
 application between its sites (i.e., between CE1 and CE2).  H0 and H1
 represent voice equipment.  In this case, a non-TE LSP means LDP, and
 the customer establishes C-TE LSP1 as a primary path and C-TE LSP2 as
 a backup path.  If the link between PE1 and CE1 or the node of PE1
 fails, C-TE LSP1 needs C-TE LSP2 as a path protection.

Kumaki, et al. Informational [Page 13] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

                             C-TE LSP1
             <----------------------------------------->
                             Non-TE LSP
                    <-------------------------->
   .............                                     .............
   . ---   --- .   ---      ---       ---      ---   . ---   --- .
   .|H0 | |CE1|---|PE1|----|P1 |-----|P2 |----|PE2|---|CE2| |H1 |.
   . ---   --- .   ---      ---       ---      ---   . ---   --- .
   .........|...   ---      ---       ---      ---   ...|.........
            +-----|PE3|----|P3 |-----|P4 |----|PE4|-----+
                   ---      ---       ---      ---
                    <-------------------------->
                             Non-TE LSP
             <----------------------------------------->
                             C-TE LSP2
   <-customer->     <------BGP/MPLS IP-VPN------>    <-customer->
      network                                           network
                        Figure 6.  Scenario VI

6. Detailed Requirements for the C-TE LSP Model

 This section describes detailed requirements for C-TE LSPs in
 BGP/MPLS IP-VPN environments.

6.1. Selective P-TE LSPs

 The solution MUST provide the ability to decide which P-TE LSPs a PE
 uses for a C-RSVP path and a C-TE LSP.  When a PE receives a native
 RSVP and/or a path message from a CE, it MUST be able to decide which
 P-TE LSPs it uses.  In this case, various kinds of P-TE LSPs exist in
 the service-provider network.  For example, the PE MUST choose an
 appropriate P-TE LSP based on local policies such as:
 1. preemption priority
 2. affinity
 3. class-type
 4. on the data plane: (Differentiated Services Code Point (DSCP) or
    Traffic Class bits)

6.2. Graceful Restart Support for C-TE LSPs

 The solution SHOULD support the graceful restart capability, where
 the C-TE LSP traffic continues to be forwarded during a PE graceful
 restart.  Graceful restart mechanisms related to this architecture
 are described in [RFC3473], [RFC3623], and [RFC4781].

Kumaki, et al. Informational [Page 14] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

6.3. Rerouting Support for C-TE LSPs

 The solution MUST provide the rerouting of a C-TE LSP in case of
 link, node, and SRLG failures, or in case of preemption.  Such
 rerouting may be controlled by a CE or by a PE, depending on the
 failure.  In a dual-homed environment, the ability to perform
 rerouting MUST be provided against a CE-PE link failure or a PE
 failure, if another CE-PE link or PE is available between the head-
 end and the tail-end of the C-TE LSP.

6.4. FRR Support for C-TE LSPs

 The solution MUST support FRR [RFC4090] features for a C-TE LSP over
 a VRF instance.
 In BGP/MPLS IP-VPN environments, a C-TE LSP from a CE traverses
 multiple PEs and Ps, albeit tunneled over a P-TE LSP.  In order to
 avoid PE-CE link/PE node/SRLG failures, a CE (a customer's head-end
 router) needs to support link protection or node protection.
 The following protection MUST be supported:
 1. CE link protection
 2. PE node protection
 3. CE node protection

6.5. Admission Control Support on P-TE LSP Head-Ends

 The solution MUST support admission control on a P-TE LSP tunnel
 head-end for C-TE LSPs.  C-TE LSPs may potentially try to reserve the
 bandwidth that exceeds the bandwidth of the P-TE LSP.  The P-TE LSP
 tunnel head-end SHOULD control the number of C-TE LSPs and/or the
 bandwidth of C-TE LSPs.  For example, the transport TE LSP head-end
 SHOULD have a configurable limit on the maximum number of C-TE LSPs
 that it can admit from a CE.  As for the amount of bandwidth that can
 be reserved by C-TE LSPs, there could be two situations:
 1. Let the P-TE LSP do its natural bandwidth admission
 2. Set a cap on the amount of bandwidth, and have the configuration
    option to:
    a. Reserve the minimum cap bandwidth or the C-TE LSP bandwidth on
       the P-TE LSP if the required bandwidth is available
    b. Reject the C-TE LSP if the required bandwidth by the C-TE LSP
       is not available

Kumaki, et al. Informational [Page 15] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

6.6. Admission Control Support for C-TE LSPs in LDP-Based Core

    Networks
 The solution MUST support admission control for a C-TE LSP at a PE in
 the LDP-based core network.  Specifically, PEs MUST have a
 configurable limit on the maximum amount of bandwidth that can be
 reserved by C-TE LSPs for a given VRF instance (i.e., for a given
 customer).  Also, a PE SHOULD have a configurable limit on the total
 amount of bandwidth that can be reserved by C-TE LSPs between PEs.

6.7. Policy Control Support for C-TE LSPs

 The solution MUST support the policy control for a C-TE LSP at a PE.
 The PE MUST be able to perform the following:
 1. Limit the rate of RSVP messages per CE link.
 2. Accept and map, or reject, requests for a given affinity.
 3. Accept and map, or reject, requests with a specified setup and/or
    preemption priorities.
 4. Accept or reject requests for fast reroutes.
 5. Ignore the requested setup and/or preemption priorities, and
    select a P-TE LSP based on a local policy that applies to the
    CE-PE link or the VRF.
 6. Ignore the requested affinity, and select a P-TE LSP based on a
    local policy that applies to the CE-PE link or the VRF.
 7. Perform mapping in the data plane between customer Traffic Class
    bits and transport P-TE LSP Traffic Class bits, as signaled per
    [RFC3270].

6.8. PCE Features Support for C-TE LSPs

 The solution SHOULD support the PCE architecture for a C-TE LSP
 establishment in the context of a VRF instance.  When a C-TE LSP is
 provided, CEs, PEs, and Ps may support PCE features ([RFC4655],
 [RFC5440]).
 In this case, CE routers or PE routers may be Path Computation
 Clients (PCCs), and PE routers and/or P routers may be PCEs.
 Furthermore, the solution SHOULD support a mechanism for dynamic PCE
 discovery.  Specifically, all PCEs are not necessarily discovered
 automatically, and only specific PCEs that know VPN routes should be
 discovered automatically.

6.9. Diversely Routed C-TE LSP Support

 The solution MUST provide for setting up diversely routed C-TE LSPs
 over the VRF instance.  These diverse C-TE LSPs MAY be traversing

Kumaki, et al. Informational [Page 16] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

 over two different P-TE LSPs that are fully disjoint within a
 service-provider network.  When a single CE has multiple uplinks that
 connect to different PEs, it is desirable that multiple C-TE LSPs
 over the VRF instance be established between a pair of LSRs.  When
 two CEs have multiple uplinks that connect to different PEs, it is
 desirable that multiple C-TE LSPs over the VRF instance be
 established between two different pairs of LSRs.  In these cases, for
 example, the following points will be beneficial to customers.
 1. load balance of the CE-to-CE traffic across diverse C-TE LSPs so
    as to minimize the traffic disruption in case of a single network
    element failure
 2. path protection (e.g., 1:1, 1:N)

6.10. Optimal Path Support for C-TE LSPs

 The solution MUST support the optimal path for a C-TE LSP over the
 VRF instance.  Depending on an application (e.g., voice and video),
 an optimal path is needed for a C-TE LSP over the VRF instance.  In
 the case of a TE LSP, an optimal route may be the shortest path based
 on the TE metric applied.  For a non-TE LSP using LDP, the IGP metric
 may be used to compute optimal paths.

6.11. Reoptimization Support for C-TE LSPs

 The solution MUST support the reoptimization of a C-TE LSP over the
 VRF instance.  These LSPs MUST be reoptimized using "make-before-
 break" [RFC3209].
 In this case, it is desirable for a CE to be configured with regard
 to the timer-based or event-driven reoptimization.  Furthermore,
 customers SHOULD be able to reoptimize a C-TE LSP manually.  To
 provide for delay-sensitive or jitter-sensitive traffic (i.e., voice
 traffic), C-TE LSP path computation and route selection are expected
 to be optimal for the specific application.

6.12. DS-TE Support for C-TE LSPs

 The solution MUST support DS-TE [RFC4124] for a C-TE LSP over the VRF
 instance.  In the event that the service provider and the customer
 have differing bandwidth constraint models, then only the service-
 provider bandwidth model should be supported.
 Applications, which have different traffic characteristics, are used
 in BGP/MPLS IP-VPN environments.  Service providers try to achieve
 the fine-grained optimization of transmission resources, efficiency,
 and further-enhanced network performance.  It may be desirable to
 perform TE at a per-class level.

Kumaki, et al. Informational [Page 17] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

 By mapping the traffic from a given Diffserv class of service on a
 separate C-TE LSP, DS-TE allows this traffic to utilize resources
 available to the given class on both shortest paths and non-shortest
 paths, and also to follow paths that meet TE constraints that are
 specific to the given class.

7. Detailed Requirements for the C-RSVP Path Model

 This section describes detailed requirements for C-RSVP paths in
 BGP/MPLS IP-VPN environments.

7.1. Admission Control between PE and CE for C-RSVP Paths

 The solution MUST support admission control at the ingress PE.  PEs
 MUST control RSVP messages per a VRF instance.

7.2. Aggregation of C-RSVP Paths by P-TE LSPs

 The solution SHOULD support C-RSVP paths aggregated by P-TE LSPs.
 P-TE LSPs SHOULD be pre-established manually or dynamically by
 operators and MAY be established if triggered by C-RSVP messages.
 Also, the P-TE LSP SHOULD support DS-TE.

7.3. Non-TE LSP Support for C-RSVP Paths

 The solution SHOULD support non-TE LSPs (i.e., LDP-based LSP, etc.).
 Non-TE LSPs are established by LDP [RFC5036] between PEs and support
 MPLS Diffserv [RFC3270].  The solution MAY support local policies to
 map the customer's reserved flow to the LSP with the appropriate
 Traffic Class at the PE.

7.4. Transparency of C-RSVP Paths

 The solution SHOULD NOT change RSVP messages from the local CE to the
 remote CE (Path, Resv, Path Error, Resv Error, etc.).  The solution
 SHOULD allow customers to receive RSVP messages transparently between
 CE sites.

8. Commonly Detailed Requirements for Two Models

 This section describes commonly detailed requirements for C-TE LSPs
 and C-RSVP paths in BGP/MPLS IP-VPN environments.

8.1. CE-PE Routing

 The solution SHOULD support the following routing configuration on
 the CE-PE links with either RSVP or RSVP-TE on the CE-PE link:

Kumaki, et al. Informational [Page 18] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

 1. static routing
 2. BGP routing
 3. OSPF
 4. OSPF-TE (RSVP-TE case only)

8.2. Complexity and Risks

 The solution SHOULD avoid introducing unnecessary complexity to the
 current operating network to such a degree that it would affect the
 stability and diminish the benefits of deploying such a solution over
 SP networks.

8.3. Backward Compatibility

 The deployment of C-RSVP paths and C-TE LSPs SHOULD avoid impacting
 existing RSVP and MPLS-TE mechanisms, respectively, but should allow
 for a smooth migration or co-existence.

8.4. Scalability Considerations

 The solution SHOULD minimize the impact on network scalability from a
 C-RSVP path and a C-TE LSP over the VRF instance.  As identified in
 earlier sections, PCE provides a method for offloading computation of
 C-TE LSPs and helps with the solution scalability.
 The solution MUST address the scalability of C-RSVP paths and
 C-TE LSPs for the following protocols.
 1. RSVP (e.g., number of RSVP messages, retained state, etc.).
 2. RSVP-TE (e.g., number of RSVP control messages, retained state,
    message size, etc.).
 3. BGP (e.g., number of routes, flaps, overload events, etc.).

8.5. Performance Considerations

 The solution SHOULD be evaluated with regard to the following
 criteria.
 1. Degree of path optimality of the C-TE LSP.
 2. TE LSP setup time.
 3. Failure and restoration time.
 4. Impact and scalability of the control plane due to added overhead.
 5. Impact and scalability of the data/forwarding plane due to added
    overhead.

Kumaki, et al. Informational [Page 19] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

8.6. Management Considerations

 The solution MUST address the manageability of C-RSVP paths and
 C-TE LSPs for the following considerations.
 1. Need for a MIB module for the control plane (including mapping of
    P-TE LSPs and C-TE LSPs) and bandwidth monitoring.
 2. Need for diagnostic tools (this includes traceroute and Ping).
 The solution MUST allow routers to support the MIB module for C-RSVP
 paths and C-TE LSPs per a VRF instance.  If a CE is managed by
 service providers, the solution MUST allow service providers to
 collect MIB information for C-RSVP paths and C-TE LSPs from the CE
 per a customer.
 Diagnostic tools can detect failures of the control plane and data
 plane for general MPLS-TE LSPs [RFC4379].  The solution MUST allow
 routers to be able to detect failures of the control plane and the
 data plane for C-TE LSPs over a VRF instance.
 MPLS Operations, Administration, and Maintenance (OAM) for C-TE LSPs
 MUST be supported within the context of VRF, except for the above.

9. Security Considerations

 Any solution should consider the following general security
 requirements:
 1. The solution SHOULD NOT divulge the service-provider topology
    information to the customer network.
 2. The solution SHOULD minimize the service-provider network's
    vulnerability to Denial of Service (DoS) attacks.
 3. The solution SHOULD minimize the misconfiguration of DSCP marking,
    preemption, and holding priorities of the customer traffic.
 The following additional security issues for C-TE LSPs relate to both
 the control plane and the data plane.
 In terms of the control plane, in both the C-RSVP path and C-TE LSP
 models, a PE receives IPv4 or IPv6 RSVP control packets from a CE.
 If the CE is a router that is not trusted by service providers, the
 PE MUST be able to limit the rate and number of IPv4 or IPv6 RSVP
 control packets.
 In terms of the data plane, in the C-TE LSP model, a PE receives
 labeled IPv4 or IPv6 data packets from a CE.  If the CE is a router
 that is not trusted by service providers, the PE MUST be able to
 limit the rate of labeled IPv4 or IPv6 data packets.  If the CE is a

Kumaki, et al. Informational [Page 20] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

 trusted router for service providers, the PE MAY be able to limit the
 rate of labeled IPv4 or IPv6 data packets.  Specifically, the PE must
 drop MPLS-labeled packets if the MPLS label was not assigned over the
 PE-CE link on which the packet was received.  The PE must also be
 able to police traffic to the traffic profile associated with the LSP
 on which traffic is received on the PE-CE link.
 Moreover, flooding RSVP/RSVP-TE control packets from malicious
 customers must be avoided.  Therefore, a PE MUST isolate the impact
 of such customers' RSVP/RSVP-TE packets from other customers.
 In the event that C-TE LSPs are diversely routed over VRF instances,
 the VRF should indicate to the CE how such diversity was provided.

10. References

10.1. Normative References

 [RFC1633]      Braden, R., Clark, D., and S. Shenker, "Integrated
                Services in the Internet Architecture: an Overview",
                RFC 1633, June 1994.
 [RFC2119]      Bradner, S., "Key words for use in RFCs to Indicate
                Requirement Levels", BCP 14, RFC 2119, March 1997.
 [RFC2210]      Wroclawski, J., "The Use of RSVP with IETF Integrated
                Services", RFC 2210, September 1997.
 [RFC3209]      Awduche, D., Berger, L., Gan, D., Li, T.,
                Srinivasan, V., and G. Swallow, "RSVP-TE: Extensions
                to RSVP for LSP Tunnels", RFC 3209, December 2001.
 [RFC3270]      Le Faucheur, F., Wu, L., Davie, B., Davari, S.,
                Vaananen, P., Krishnan, R., Cheval, P., and
                J. Heinanen, "Multi-Protocol Label Switching (MPLS)
                Support of Differentiated Services", RFC 3270,
                May 2002.
 [RFC3473]      Berger, L., Ed., "Generalized Multi-Protocol Label
                Switching (GMPLS) Signaling Resource ReserVation
                Protocol-Traffic Engineering (RSVP-TE) Extensions",
                RFC 3473, January 2003.
 [RFC3623]      Moy, J., Pillay-Esnault, P., and A. Lindem, "Graceful
                OSPF Restart", RFC 3623, November 2003.

Kumaki, et al. Informational [Page 21] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

 [RFC4090]      Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed.,
                "Fast Reroute Extensions to RSVP-TE for LSP Tunnels",
                RFC 4090, May 2005.
 [RFC4124]      Le Faucheur, F., Ed., "Protocol Extensions for Support
                of Diffserv-aware MPLS Traffic Engineering", RFC 4124,
                June 2005.
 [RFC4364]      Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
                Networks (VPNs)", RFC 4364, February 2006.
 [RFC4379]      Kompella, K. and G. Swallow, "Detecting Multi-Protocol
                Label Switched (MPLS) Data Plane Failures", RFC 4379,
                February 2006.
 [RFC4655]      Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
                Computation Element (PCE)-Based Architecture",
                RFC 4655, August 2006.
 [RFC4781]      Rekhter, Y. and R. Aggarwal, "Graceful Restart
                Mechanism for BGP with MPLS", RFC 4781, January 2007.
 [RFC5036]      Andersson, L., Ed., Minei, I., Ed., and B. Thomas,
                Ed., "LDP Specification", RFC 5036, October 2007.
 [RFC5462]      Andersson, L. and R. Asati, "Multiprotocol Label
                Switching (MPLS) Label Stack Entry: "EXP" Field
                Renamed to "Traffic Class" Field", RFC 5462,
                February 2009.

10.2. Informative References

 [RSVP-L3VPN]   Davie, B., Le Faucheur, F., and A. Narayanan, "Support
                for RSVP in Layer 3 VPNs", Work in Progress,
                November 2009.
 [RFC4804]      Le Faucheur, F., Ed., "Aggregation of Resource
                ReSerVation Protocol (RSVP) Reservations over MPLS
                TE/DS-TE Tunnels", RFC 4804, February 2007.
 [RFC5330]      Vasseur, JP., Ed., Meyer, M., Kumaki, K., and
                A. Bonda, "A Link-Type sub-TLV to Convey the Number of
                Traffic Engineering Label Switched Paths Signalled
                with Zero Reserved Bandwidth across a Link", RFC 5330,
                October 2008.

Kumaki, et al. Informational [Page 22] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

 [RFC5440]      Vasseur, JP., Ed., and JL. Le Roux, Ed., "Path
                Computation Element (PCE) Communication Protocol
                (PCEP)", RFC 5440, March 2009.

11. Acknowledgments

 The authors would like to express thanks to Nabil Bitar,
 David McDysan, and Daniel King for their helpful and useful comments
 and feedback.

Kumaki, et al. Informational [Page 23] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

Appendix A. Reference Model

 In this appendix, a C-RSVP path, a C-TE LSP, and a P-TE LSP are
 explained.
 All scenarios in this appendix assume the following:
  1. A P-TE LSP is established between PE1 and PE2. This LSP is used by

the VRF instance to forward customer packets within a BGP/MPLS

   IP-VPN.
  1. The service provider has ensured that enough bandwidth is available

to meet the service requirements.

A.1. End-to-End C-RSVP Path Model

 A C-RSVP path and a P-TE LSP are shown in Figure 7, in the context of
 a BGP/MPLS IP-VPN.  A P-TE LSP may be a non-TE LSP (i.e., LDP) in
 some cases.  In the case of a non-TE mechanism, however, it may be
 difficult to guarantee an end-to-end bandwidth, as resources are
 shared.
 CE0/CE1 requests an e2e C-RSVP path to CE3/CE2 with the bandwidth
 reservation of X.  At PE1, this reservation request received in the
 context of a VRF will get aggregated onto a pre-established P-TE LSP,
 or trigger the establishment of a new P-TE LSP.  It should be noted
 that C-RSVP sessions across different BGP/MPLS IP-VPNs can be
 aggregated onto the same P-TE LSP between the same PE pair, achieving
 further scalability.  [RFC4804] defines this scenario in more detail.
 The RSVP control messages (e.g., an RSVP PATH message and an RSVP
 RESV message) exchanged among CEs are forwarded by IP packets through
 the BGP/MPLS IP-VPN.  After CE0 and/or CE1 receive a reservation
 message from CE2 and/or CE3, CE0/CE1 establishes a C-RSVP path
 through the BGP/MPLS IP-VPN.

Kumaki, et al. Informational [Page 24] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

                            C-RSVP path
              <------------------------------------------>
                             P-TE LSP
                   <--------------------------->
  .............                                     .............
  . ---   --- .   ---      ---       ---      ---   . ---   --- .
  .|CE0| |CE1|---|PE1|----|P1 |-----|P2 |----|PE2|---|CE2| |CE3|.
  . ---   --- .   ---      ---       ---      ---   . ---   --- .
  .............                                     .............
                 ^                               ^
                 |                               |
            VRF instance                    VRF instance
   <-customer->    <------BGP/MPLS IP-VPN------>     <-customer->
     network                                           network
       or                                                or
     another                                           another
 service-provider                                  service-provider
     network                                           network
                   Figure 7.  e2e C-RSVP Path Model

A.2. End-to-End C-TE LSP Model

 A C-TE LSP and a P-TE LSP are shown in Figure 8, in the context of a
 BGP/MPLS IP-VPN.  A P-TE LSP may be a non-TE LSP (i.e., LDP) in some
 cases.  As described in the previous sub-section, it may be difficult
 to guarantee an end-to-end QoS in some cases.
 CE0/CE1 requests an e2e TE LSP path to CE3/CE2 with the bandwidth
 reservation of X.  At PE1, this reservation request received in the
 context of a VRF will get aggregated onto a pre-established P-TE LSP,
 or trigger the establishment of a new P-TE LSP.  It should be noted
 that C-TE LSPs across different BGP/MPLS IP-VPNs can be aggregated
 onto the same P-TE LSP between the same PE pair, achieving further
 scalability.
 The RSVP-TE control messages (e.g., an RSVP PATH message and an RSVP
 RESV message) exchanged among CEs are forwarded by a labeled packet
 through the BGP/MPLS IP-VPN.  After CE0 and/or CE1 receive a
 reservation message from CE2 and/or CE3, CE0/CE1 establishes a
 C-TE LSP through the BGP/MPLS IP-VPN.
 A P-TE LSP is established between PE1 and PE2.  This LSP is used by
 the VRF instance to forward customer packets within the BGP/MPLS
 IP-VPN.

Kumaki, et al. Informational [Page 25] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

                               C-TE LSP
      <------------------------------------------------------->
                                  or
                               C-TE LSP
             <----------------------------------------->
                               P-TE LSP
                    <--------------------------->
   .............                                     .............
   . ---   --- .   ---      ---       ---      ---   . ---   --- .
   .|CE0| |CE1|---|PE1|----|P1 |-----|P2 |----|PE2|---|CE2| |CE3|.
   . ---   --- .   ---      ---       ---      ---   . ---   --- .
   .............                                     .............
                  ^                               ^
                  |                               |
             VRF instance                    VRF instance
    <-customer->   <-------BGP/MPLS IP-VPN------->    <-customer->
      network                                           network
         or                                                or
      another                                           another
  service-provider                                  service-provider
      network                                           network
                     Figure 8.  e2e C-TE LSP Model

Kumaki, et al. Informational [Page 26] RFC 5824 Supporting RSVP/RSVP-TE over BGP/MPLS IP-VPN April 2010

Authors' Addresses

 Kenji Kumaki (Editor)
 KDDI Corporation
 Garden Air Tower
 Iidabashi, Chiyoda-ku
 Tokyo 102-8460, JAPAN
 EMail: ke-kumaki@kddi.com
 Raymond Zhang
 BT
 Farady Building, PP1.21
 1 Knightrider Street
 London EC4V 5BT
 UK
 EMail: raymond.zhang@bt.com
 Yuji Kamite
 NTT Communications Corporation
 Granpark Tower
 3-4-1 Shibaura, Minato-ku
 Tokyo  108-8118
 Japan
 EMail: y.kamite@ntt.com

Kumaki, et al. Informational [Page 27]

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