MPLS Working Group D. Frost, Ed.
Internet-Draft Cisco Systems
Intended status: Informational M. Bocci, Ed.
Expires: January 09, 2012 Alcatel-Lucent
L. Berger, Ed.
LabN Consulting
July 08, 2011

A Framework for Point-to-Multipoint MPLS in Transport Networks
draft-fbb-mpls-tp-p2mp-framework-03

Abstract

The Multiprotocol Label Switching (MPLS) Transport Profile (MPLS-TP) is the common set of MPLS protocol functions defined to enable the construction and operation of packet transport networks. The MPLS-TP supports both point-to-point and point-to-multipoint transport paths. This document defines the elements and functions of the MPLS-TP architecture applicable specifically to supporting point-to-multipoint transport paths.

This document is a product of a joint Internet Engineering Task Force (IETF) / International Telecommunication Union Telecommunication Standardization Sector (ITU-T) effort to include an MPLS Transport Profile within the IETF MPLS and PWE3 architectures to support the capabilities and functionalities of a packet transport network.

Status of this Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/.

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This Internet-Draft will expire on January 09, 2012.

Copyright Notice

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Table of Contents

1. Introduction

The Multiprotocol Label Switching (MPLS) Transport Profile (MPLS-TP) is the common set of MPLS protocol functions defined to meet the requirements specified in [RFC5654]. The MPLS-TP Framework [I-D.ietf-mpls-tp-framework] provides an overall introduction to the MPLS-TP and defines the general architecture of the Transport Profile, as well as those aspects specific to point-to-point transport paths. The purpose of this document is to define the elements and functions of the MPLS-TP architecture applicable specifically to supporting point-to-multipoint transport paths.

This document is a product of a joint Internet Engineering Task Force (IETF) / International Telecommunication Union Telecommunication Standardization Sector (ITU-T) effort to include an MPLS Transport Profile within the IETF MPLS and PWE3 architectures to support the capabilities and functionalities of a packet transport network.

1.1. Scope

This document defines the elements and functions of the MPLS-TP architecture related to supporting point-to-multipoint transport paths. The reader is referred to [I-D.ietf-mpls-tp-framework] for those aspects of the MPLS-TP architecture that are generic, or concerned specifically with point-to-point transport paths.

1.2. Terminology

Term Definition
LSP Label Switched Path
MPLS-TP MPLS Transport Profile
SDH Synchronous Digital Hierarchy
ATM Asynchronous Transfer Mode
OTN Optical Transport Network
OAM Operations, Administration and Maintenance
G-ACh Generic Associated Channel
GAL G-ACh Label
MEP Maintenance End Point
MIP Maintenance Intermediate Point
APS Automatic Protection Switching
SCC Signaling Communication Channel
MCC Management Communication Channel
EMF Equipment Management Function
FM Fault Management
CM Configuration Management
PM Performance Management
LSR Label Switching Router
MPLS-TE MPLS Traffic Engineering
P2MP Point-to-multipoint
PW Pseudowire

1.2.1. Additional Definitions and Terminology

Detailed definitions and additional terminology may be found in [I-D.ietf-mpls-tp-framework] and [RFC5654].

1.3. Applicability

The point-to-multipoint connectivity provided by an MPLS-TP network is based on the point-to-multipoint connectivity provided by MPLS networks. MPLS TE-LSP support is discussed in [RFC4875] and [RFC5332], and PW support is being developed based on [I-D.ietf-pwe3-p2mp-pw-requirements] and [I-D.ietf-l2vpn-vpms-frmwk-requirements]. MPLS-TP point-to-multipoint connectivity is analogous to that provided by traditional transport technologies such as Optical Transport Network (OTN) point-to-multipoint [ref?] and optical drop-and-continue [ref?], and thus supports the same class of traditional applications.

2. MPLS Transport Profile Point-to-Multipoint Requirements

The requirements for MPLS-TP are specified in [RFC5654], [I-D.ietf-mpls-tp-oam-requirements], and [I-D.ietf-mpls-tp-nm-req]. This section provides a brief summary of point-to-multipoint transport requirements as set out in those documents; the reader is referred to the documents themselves for the definitive and complete list of requirements.

3. Architecture

The overall architecture of the MPLS Transport Profile is defined in [I-D.ietf-mpls-tp-framework]. The architecture for point-to-multipoint MPLS-TP comprises the following additional elements and functions:

The following subsections summarise the encapsulation and forwarding of point-to-multipoint traffic within an MPLS-TP network, and the encapsulation options for delivery of traffic to and from MPLS-TP Customer Edge devices when the network is providing a packet transport service.

3.1. MPLS-TP Encapsulation and Forwarding

Packet encapsulation and forwarding for MPLS-TP point-to-multipoint LSPs is identical to that for MPLS-TE point-to-multipoint LSPs. MPLS-TE point-to-multipoint LSPs were introduced in [RFC4875] and the related data-plane behaviour was further clarified in [RFC5332]. MPLS-TP allows for both upstream-assigned and downstream-assigned labels for use with point-to-multipoint LSPs.

Packet encapsulation and forwarding for point-to-multipoint PWs is currently being defined by the PWE3 Working Group [I-D.raggarwa-pwe3-p2mp-pw-encaps].

4. Operations, Administration and Maintenance (OAM)

The overall OAM architecture for MPLS-TP is defined in [I-D.ietf-mpls-tp-oam-framework].

[Editor's note: This section will contain a summary of point-to-multipoint OAM as described in the OAM Framework.]

5. Control Plane

The overall control plane architecture for MPLS-TP is defined in [I-D.abfb-mpls-tp-control-plane-framework].

[Editor's note: This section will contain a summary of the point-to-multipoint control plane as described in the Control Plane Framework.]

5.1. Point-to-Multipoint LSP Control Plane

The MPLS-TP control plane for point-to-multipoint LSPs uses Generalized MPLS (GMPLS) and is based on Resource Reservation Protocol - Traffic Engineering (RSVP-TE) for point-to-multipoint LSPs as defined in [RFC4875].

5.2. Point-to-Multipoint PW Control Plane

The MPLS-TP control plane for point-to-multipoint pseudowires is based on the LDP P2MP signaling extensions for PWs defined in [I-D.martini-pwe3-p2mp-pw].

6. Survivability

The overall survivability architecture for MPLS-TP is defined in [I-D.ietf-mpls-tp-survive-fwk].

[Editor's note: This section will contain a summary of point-to-multipoint survivability as described in the Survivability Framework.]

7. Network Management

The network management architecture and requirements for MPLS-TP are specified in [I-D.ietf-mpls-tp-nm-req]. They derive from the generic specifications described in ITU-T G.7710/Y.1701 [G.7710] for transport technologies. They also incorporate the OAM requirements for MPLS Networks [RFC4377] and MPLS-TP Networks [I-D.ietf-mpls-tp-oam-requirements] and expand on those requirements to cover the modifications necessary for fault, configuration, performance, and security in a transport network.

[Editor's note: Decide what if anything needs to be said about P2MP-specific network management considerations.]

8. Security Considerations

General security considerations for MPLS-TP are noted in [I-D.ietf-mpls-tp-framework], and security considerations for point-to-multipoint PWs and LSPs in the documents that define them. This document introduces no new security considerations in itself.

9. IANA Considerations

IANA considerations resulting from specific elements of MPLS-TP functionality are detailed in the documents specifying that functionality. This document introduces no additional IANA considerations in itself.

10. References

10.1. Normative References

[RFC5654] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N. and S. Ueno, "Requirements of an MPLS Transport Profile", RFC 5654, September 2009.
[I-D.ietf-mpls-tp-framework] Bocci, M, Bryant, S, Frost, D, Levrau, L and L Berger, "A Framework for MPLS in Transport Networks", Internet-Draft draft-ietf-mpls-tp-framework-12, May 2010.
[RFC4875] Aggarwal, R., Papadimitriou, D. and S. Yasukawa, "Extensions to Resource Reservation Protocol - Traffic Engineering (RSVP-TE) for Point-to-Multipoint TE Label Switched Paths (LSPs)", RFC 4875, May 2007.
[RFC5332] Eckert, T., Rosen, E., Aggarwal, R. and Y. Rekhter, "MPLS Multicast Encapsulations", RFC 5332, August 2008.

10.2. Informative References

, "
[I-D.ietf-mpls-tp-oam-requirements] Vigoureux, M and D Ward, "Requirements for OAM in MPLS Transport Networks", Internet-Draft draft-ietf-mpls-tp-oam-requirements-06, March 2010.
[I-D.ietf-mpls-tp-oam-framework] Allan, D, Busi, I, Niven-Jenkins, B, Fulignoli, A, Hernandez-Valencia, E, Levrau, L, Sestito, V, Sprecher, N, Helvoort, H, Vigoureux, M, Weingarten, Y and R Winter, "Operations, Administration and Maintenance Framework for MPLS-based Transport Networks", Internet-Draft draft-ietf-mpls-tp-oam-framework-11, February 2011.
[I-D.abfb-mpls-tp-control-plane-framework] Andersson, L, Berger, L, Fang, L, Bitar, N, Takacs, A, Vigoureux, M and E Bellagamba, "MPLS-TP Control Plane Framework", Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02, February 2010.
[I-D.ietf-mpls-tp-nm-req] Mansfield, S and K Lam, "MPLS TP Network Management Requirements", Internet-Draft draft-ietf-mpls-tp-nm-req-06, October 2009.
[I-D.ietf-mpls-tp-survive-fwk] Sprecher, N and A Farrel, "Multiprotocol Label Switching Transport Profile Survivability Framework", Internet-Draft draft-ietf-mpls-tp-survive-fwk-06, June 2010.
[I-D.ietf-l2vpn-vpms-frmwk-requirements] Kamite, Y, JOUNAY, F, Niven-Jenkins, B, Brungard, D and L Jin, "Framework and Requirements for Virtual Private Multicast Service (VPMS)", Internet-Draft draft-ietf-l2vpn-vpms-frmwk-requirements-04, July 2011.
[I-D.ietf-pwe3-p2mp-pw-requirements] Heron, G, Wang, L, Aggarwal, R, Vigoureux, M, Bocci, M, Jin, L, JOUNAY, F, Niger, P, Kamite, Y, DeLord, S and L Martini, "Requirements and Framework for Point-to-Multipoint Pseudowires over MPLS PSNs", Internet-Draft draft-ietf-pwe3-p2mp-pw-requirements-05, September 2011.
[I-D.martini-pwe3-p2mp-pw] Martini, L, Boutros, S, Sivabalan, S, Konstantynowicz, M, Vecchio, G, Nadeau, T, JOUNAY, F, Niger, P, Kamite, Y, Jin, L, Vigoureux, M, Ciavaglia, L and S Delord, "Signaling Root-Initiated Point-to-Multipoint Pseudowires using LDP", Internet-Draft draft-martini-pwe3-p2mp-pw-01, October 2009.
[I-D.raggarwa-pwe3-p2mp-pw-encaps] Aggarwal, R and F JOUNAY, "Point-to-Multipoint Pseudo-Wire Encapsulation", Internet-Draft draft-raggarwa-pwe3-p2mp-pw-encaps-01, March 2010.
[RFC4377] Nadeau, T., Morrow, M., Swallow, G., Allan, D. and S. Matsushima, "Operations and Management (OAM) Requirements for Multi-Protocol Label Switched (MPLS) Networks", RFC 4377, February 2006.
[G.7710] ITU-T Recommendation G.7710/Y.1701 (07/07), "Common equipment management function requirements"", 2005.

Authors' Addresses

Dan Frost editor Cisco Systems EMail: danfrost@cisco.com
Matthew Bocci editor Alcatel-Lucent Voyager Place, Shoppenhangers Road Maidenhead, Berks SL6 2PJ United Kingdom EMail: matthew.bocci@alcatel-lucent.com
Lou Berger editor LabN Consulting Phone: +1-301-468-9228 EMail: lberger@labn.net