draft-ietf-pce-vpn-req-01.txt   draft-ietf-pce-vpn-req-02.txt 
Network Working Group S. Yasukawa Network Working Group S. Yasukawa
Internet Draft NTT Internet Draft NTT
Category: Informational A. Farrel (Ed.) Category: Informational A. Farrel
Created: October 19, 2009 Old Dog Consulting Old Dog Consulting
Expires: April 19, 2010 Expires: March 17, 2011
September 17, 2010
PCC-PCE Communication Requirements for VPNs PCC-PCE Communication Requirements for VPNs
draft-ietf-pce-vpn-req-01.txt draft-ietf-pce-vpn-req-02.txt
Abstract
The Path Computation Element (PCE) provides path computation
functions in support of traffic engineering in Multiprotocol Label
Switching (MPLS) and Generalized MPLS (GMPLS) networks.
An important application of MPLS and GMPLS networks is Virtual
Private Networks (VPNs) that may be constructed using Label Switched
Paths (LSPs) in the MPLS and GMPLS networks as VPN tunnels. PCE may
be applied as a tool to compute the paths of such tunnels in order to
achieve better use of the network resources and to provide better
levels of service to the VPN customers.
Generic requirements for a communication protocol between Path
Computation Clients (PCCs) and PCEs are presented in "Path
Computation Element (PCE) Communication Protocol Generic
Requirements". This document complements the generic requirements and
presents a detailed set of PCC-PCE communication protocol
requirements that are specific to the application of PCE to VPNs.
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
skipping to change at page 1, line 33 skipping to change at page 2, line 5
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
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
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
Abstract Copyright Notice
The Path Computation Element (PCE) provides path computation
functions in support of traffic engineering in Multiprotocol Label
Switching (MPLS) and Generalized MPLS (GMPLS) networks.
An important application of MPLS and GMPLS networks is Virtual Copyright (c) 2010 IETF Trust and the persons identified as the
Private Networks (VPNs) that may be constructed using Label Switched document authors. All rights reserved.
Paths (LSPs) in the MPLS and GMPLS networks as VPN tunnels. PCE may
be applied as a tool to compute the paths of such tunnels in order to
achieve better use of the network resources and to provide better
levels of service to the VPN customers.
Generic requirements for a communication protocol between Path This document is subject to BCP 78 and the IETF Trust's Legal
Computation Clients (PCCs) and PCEs are presented in "Path Provisions Relating to IETF Documents
Computation Element (PCE) Communication Protocol Generic (http://trustee.ietf.org/license-info) in effect on the date of
Requirements". This document complements the generic requirements and publication of this document. Please review these documents
presents a detailed set of PCC-PCE communication protocol carefully, as they describe your rights and restrictions with respect
requirements that are specific to the application of PCE to VPNs. 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.
Contents Contents
1. Introduction ................................................... 3 1. Introduction ................................................... 3
2. Terminology .................................................... 4 2. Terminology .................................................... 4
2.1. Conventions used in this document ............................ 4 2.1. Conventions used in this document ............................ 4
2.2. Specific Terminology ......................................... 4 2.2. Specific Terminology ......................................... 4
3. Core Network Requirements in Support of VPNs ................... 4 3. Core Network Requirements in Support of VPNs ................... 4
3.1. VPN-Specific Behavior ........................................ 5 3.1. VPN-Specific Behavior ........................................ 5
3.1.1. Per-VPN Policy ............................................. 5 3.1.1. Per-VPN Policy ............................................. 5
skipping to change at page 4, line 17 skipping to change at page 4, line 30
responses between Path Computation Clients (PCCs) and PCEs, and also responses between Path Computation Clients (PCCs) and PCEs, and also
between PCEs. Generic requirements for PCECP are presented in between PCEs. Generic requirements for PCECP are presented in
[RFC4657]. PCECP is described in [RFC5440]. [RFC4657]. PCECP is described in [RFC5440].
This document presents a set of requirements for the Path Computation This document presents a set of requirements for the Path Computation
Element Communication Protocol (PCECP) when PCE is used in support of Element Communication Protocol (PCECP) when PCE is used in support of
VPNs. VPNs.
Specific requirements for PCECP in support of point-to-multipoint Specific requirements for PCECP in support of point-to-multipoint
path computation such as might be used in support of multicast VPNs path computation such as might be used in support of multicast VPNs
are described in [PCE-P2MP-REQ]. are described in [RFC5862].
2. Terminology 2. Terminology
2.1. Conventions used in this document 2.1. Conventions used in this document
For clarity of specification of requirements, the key words "MUST", For clarity of specification of requirements, the key words "MUST",
"MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT",
"RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be
interpreted as described in RFC 2119 [RFC2119]. interpreted as described in RFC 2119 [RFC2119].
skipping to change at page 9, line 28 skipping to change at page 9, line 35
The computation of the routes for P2MP trees is non-trivial as The computation of the routes for P2MP trees is non-trivial as
suitable branch nodes must be located within the core network. The suitable branch nodes must be located within the core network. The
computation is made more complex by various factors including computation is made more complex by various factors including
different replication capabilities of the core network nodes and different replication capabilities of the core network nodes and
different objective optimization criteria (such as least sum cost different objective optimization criteria (such as least sum cost
paths known as Steiner trees, and shortest paths to each paths known as Steiner trees, and shortest paths to each
destination). destination).
The complexity of the P2MP computation makes it particularly suitable The complexity of the P2MP computation makes it particularly suitable
to offload to a dedicated PCE [PCE-P2MP-REQ]. to offload to a dedicated PCE [RFC5862].
3.6.3. Aggregation onto P2MP LSPs 3.6.3. Aggregation onto P2MP LSPs
Aggregation of traffic from multicast VPNs onto core P2MP LSPs is Aggregation of traffic from multicast VPNs onto core P2MP LSPs is
more complicated than for unicast traffic. In the unicast case (see more complicated than for unicast traffic. In the unicast case (see
Section 3.5.1) it is possible for all traffic between a pair of PEs Section 3.5.1) it is possible for all traffic between a pair of PEs
to share the same tunnel, but in the multicast case, sharing a tunnel to share the same tunnel, but in the multicast case, sharing a tunnel
requires that there is a common set of egress PEs or that receiving requires that there is a common set of egress PEs or that receiving
PEs can discard unwanted traffic. Various solutions to this problem PEs can discard unwanted traffic. Various solutions to this problem
are possible: each requires that the paths of P2MP LSPs are computed are possible: each requires that the paths of P2MP LSPs are computed
skipping to change at page 11, line 46 skipping to change at page 12, line 8
requirements. This requirement is already covered in [RFC4657]. requirements. This requirement is already covered in [RFC4657].
CE-CE protection requires that a path computation request MUST be CE-CE protection requires that a path computation request MUST be
able to request specific diversity from another, previously computed able to request specific diversity from another, previously computed
path by specifying the links and nodes of that path. This requirement path by specifying the links and nodes of that path. This requirement
for exclusions is already covered in [RFC4657]. for exclusions is already covered in [RFC4657].
4.6. Point-to-Multipoint 4.6. Point-to-Multipoint
The requirements for PCECP to support path computation for P2MP LSPs The requirements for PCECP to support path computation for P2MP LSPs
are presented in [PCE-P2MP-REQ]. are presented in [RFC5862].
4.7. Incorporating Path Calculation During VPN Membership Discovery 4.7. Incorporating Path Calculation During VPN Membership Discovery
In order for a PE (PCC) to request a PCE to calculate PE-to-PE VPN In order for a PE (PCC) to request a PCE to calculate PE-to-PE VPN
paths, and in order for the PE to set up these LSPs during the VPN paths, and in order for the PE to set up these LSPs during the VPN
establishment/addition/deletion process, the PCE MUST monitor VPN establishment/addition/deletion process, the PCE MUST monitor VPN
membership discovery. In this context, "monitor" means that the PCE's membership discovery. In this context, "monitor" means that the PCE's
network map MUST be updated to include VPN membership information. network map MUST be updated to include VPN membership information.
For further discussion of how the PCE network map may be constructed For further discussion of how the PCE network map may be constructed
refer to [RFC4655]. refer to [RFC4655].
skipping to change at page 15, line 46 skipping to change at page 16, line 9
(PCECP)", RFC 5376, November 2008. (PCECP)", RFC 5376, November 2008.
[RFC5394] Bryskin, I., Papadimitriou, D., and Berger, L., [RFC5394] Bryskin, I., Papadimitriou, D., and Berger, L.,
"Policy-Enabled Path Computation Framework", RFC "Policy-Enabled Path Computation Framework", RFC
5394, December 2008. 5394, December 2008.
[RFC5440] Vasseur, JP., et al., "Path Computation Element [RFC5440] Vasseur, JP., et al., "Path Computation Element
(PCE) Communication Protocol (PCEP)", RFC 5440, (PCE) Communication Protocol (PCEP)", RFC 5440,
March 2009. March 2009.
[RFC5862] Yasukawa, S. and Farrel, A., "Path Computation
Clients (PCC) - Path Computation Element (PCE)
Requirements for Point-to-Multipoint MPLS-TE",
RFC 5862, June 2010.
[PCE-INTER-LAYER] Oki, E., "PCC-PCE Communication Requirements for [PCE-INTER-LAYER] Oki, E., "PCC-PCE Communication Requirements for
Inter-Layer Traffic Engineering", draft-ietf-pce- Inter-Layer Traffic Engineering", draft-ietf-pce-
inter-layer-req, work in progress. inter-layer-req, work in progress.
[PCE-P2MP-REQ] Yasukawa, S. and Farrel, A., "PCC-PCE Communication 10. Authors' Addresses
Requirements for Point-to-Multipoint Traffic
Engineering", draft-ietf-pce-p2mp-req, work in
progress.
10. Author's Address
Seisho Yasukawa (Ed.) Seisho Yasukawa
NTT Corporation NTT Corporation
9-11, Midori-Cho 3-Chome 9-11, Midori-Cho 3-Chome
Musashino-Shi, Tokyo 180-8585, Musashino-Shi, Tokyo 180-8585,
Japan Japan
Email: yasukawa.seisho@lab.ntt.co.jp Email: yasukawa.seisho@lab.ntt.co.jp
Adrian Farrel Adrian Farrel
Old Dog Consulting Old Dog Consulting
EMail: adrian@olddog.co.uk EMail: adrian@olddog.co.uk
Full Copyright Statement
Copyright (c) 2009 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 in effect on the date of
publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document.
 End of changes. 12 change blocks. 
31 lines changed or deleted 47 lines changed or added

This html diff was produced by rfcdiff 1.39. The latest version is available from http://tools.ietf.org/tools/rfcdiff/