Internet Engineering Task Force R. Martinotti, Ed. Internet-Draft D. Caviglia Intended status: Informational Ericsson Expires: May 13, 2010 N. Sprecher Nokia Siemens Networks A. D'Alessandro Telecom Italia November 9, 2009 Network Partitioning deployment scenario between MPLS-TP and IP/MPLS draft-martinotti-mpls-tp-iw-partition-00 Abstract Purpose of this ID is to illustrate deployment scenarios between network supporting MPLS-TP and network supporting IP/MPLS, where there is a network partitioning relationship between them. Main interworking aspects, issues and open points are highlighted. This document is a product of a joint Internet Engineering Task Force (IETF) / International Telecommunications Union Telecommunications 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 to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on May 13, 2010. Martinotti, et al. Expires May 13, 2010 [Page 1] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 Copyright Notice 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 (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 BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Background . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2. Scope of this document . . . . . . . . . . . . . . . . . . 3 2. Conventions used in this document . . . . . . . . . . . . . . 3 3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 4 4. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 5. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 5.1. Network Partitioning . . . . . . . . . . . . . . . . . . . 5 6. Elements used in the figures . . . . . . . . . . . . . . . . . 6 7. Network Partitioning . . . . . . . . . . . . . . . . . . . . . 6 7.1. Border Node . . . . . . . . . . . . . . . . . . . . . . . 7 7.1.1. Multisegment Pseudowire . . . . . . . . . . . . . . . 7 7.1.2. LSP stitching . . . . . . . . . . . . . . . . . . . . 10 7.2. Border Link . . . . . . . . . . . . . . . . . . . . . . . 12 7.2.1. Multisegment Pseudowire . . . . . . . . . . . . . . . 12 7.2.2. LSP stitching . . . . . . . . . . . . . . . . . . . . 15 8. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 17 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 17 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 12. Security Considerations . . . . . . . . . . . . . . . . . . . 17 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17 13.1. Normative References . . . . . . . . . . . . . . . . . . . 17 13.2. Informative References . . . . . . . . . . . . . . . . . . 18 Appendix A. Additional Stuff . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18 Martinotti, et al. Expires May 13, 2010 [Page 2] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 This Informational Internet-Draft is aimed at achieving IETF Consensus before publication as an RFC and will be subject to an IETF Last Call. [RFC Editor, please remove this note before publication as an RFC and insert the correct Streams Boilerplate to indicate that the published RFC has IETF Consensus.] 1. Introduction 1.1. Background 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. In the MPLS-TP requirements [RFC 5654] it is highlighted that an MPLS-TP architecture must allow interworking with new and already deployed IP/MPLS networks. 1.2. Scope of this document This document illustrates the most likely deployment scenarios between MPLS-TP and IP/MPLS, in case of network partitioning relationship between them. For each of the examined scenarios interworking aspects, limitations, issues and open points, with particular focus on OAM capabilities, are provided. The main architectural construct considered in this document foresees PWE3 Protocol Stack Reference Model, however also MPLS Protocol Stack Reference Model is used. See [draft mpls-tp framework] for details. Note: due to the early level of definition of CP of MPLS-TP, any possible interaction between CP of IP/MPLS and CP of MPLS-TP is left for further study. 2. Conventions used in this document 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]. Martinotti, et al. Expires May 13, 2010 [Page 3] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 3. Problem Statement This document addresses the case of network decomposition related to partitioning relationship. Interworking aspects, limitations, issues and open points are described. Note: The presented scenarios are not intended to be comprehensive. 4. Acronyms CLI Client ETH Ethernet MAC Layer LER Label Edge Router LSP Label Switched Path LSR Label Switch Router MAC Media Access Control MS-PW Multi Segment PW PE Provider Edge PHY Physical Layer PW Pseudowire SRV Server SS-PW Single Segment PW S-PE Switching Provider Edge T-PE Terminating Provider Edge 5. Terminology The following terminology is used within this document: o IP/MPLS NE (Network Element): a NE that supports IP/MPLS functions o IP/MPLS Network: a network in which IP/MPLS NEs are deployed Martinotti, et al. Expires May 13, 2010 [Page 4] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 o MPLS-TP NE: a NE that supports MPLS-TP functions o MPLS-TP Network: a network in which MPLS-TP NEs are deployed o Node: either MPLS-TP NE, IP/MPLS NE or CE (Customer Edge) o Ingress direction: from client to network o Egress direction: from network to client For each of the scenarios described in this document, two paragraphs may appear, one related to possible issues already envisaged by the authors (Open Issues), the other related to aspects still left for further study and/or definition (Open Points). This Section provides some terminology about network partitioning. Primarily source of those definitions is [ITU-T G.805]. Readers already familiar with these concepts can skip this Section. 5.1. Network Partitioning The following figure illustrates the Network Partitioning concept: ___ ___ ____ ____ ___ ___ _/ \___/ \ _/ \__ _/ \___/ \ _/ \__ / \__/ \ / \__/ \_ / \ | / \ | Sub-Network Domain 1 |+++++| Sub-Network Domain 2 | \ / | \ / \ __ ___ __ _/ \ ___ ___ __ _/ \_/ \____/ \___/ \____/ \_/ \____/ \___/ \___/ Network Partitioning Figure 1 The boundary between the two subnetworks can be a link (as defined by [ITU-T G.805]), but also a Node, which in this case SHALL be able to handle the technologies of both subnetworks. The two subnetworks are at the same level. Some readers will also call this concept "Peer model". Martinotti, et al. Expires May 13, 2010 [Page 5] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 6. Elements used in the figures A legenda of the symbols, which are most used in the following Sections, is provided, in order to facilitate comprehension of the scenarios. Node: ----- Direct connection - - - Virtual connection ..... one or more direct connections Layers: | Termination + Connection <-> Stitching OAM: > or < MEP (Maintenance Association End Point) O MIP (Maintenance Association Intermediate Point) Figure 2 7. Network Partitioning This Section provides some deployment scenarios, using the partitioning concept described in Section 5. In the rest of this Section the following assumptions apply: o Customer network is carried partly over IP/MPLS subnetwork (e.g. via PW encapsulation) and partly over MPLS-TP subnetwork. o IP/MPLS network is deployed over Ethernet (at least on interfaces interconnecting to the MPLS-TP subnetwork) o MPLS-TP subnetwork is deployed over Ethernet, however other server layers are possible (not shown in this document) For the purposes of this Section, MPLS-TP subnetwork is deployed between a CE and an IP/MPLS subnetwork. Other kinds of deployment are possible (not shown in this document), for instance: o More than two subnetworks are deployed between the CEs Martinotti, et al. Expires May 13, 2010 [Page 6] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 o MPLS-TP can be deployed between two subnetworks 7.1. Border Node Main features to be taken into account: o MultiSegment Pseudowire o LSP Stitching o Network Interworking o End-to-End OAM support o Interaction between DP (Data Plane) of IP/MPLS and DP of MPLS-TP o Interaction between CP (Control Plane) of IP/MPLS and CP of MPLS-TP o Interaction between MP (Management Plane) of IP/MPLS and MP of MPLS-TP o No need of PHP handling by MPLS-TP node 7.1.1. Multisegment Pseudowire The following figure illustrates the functional interworking among the networks: Martinotti, et al. Expires May 13, 2010 [Page 7] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 Networks: Customer Network +---+ - - - - - - - - - - - - - - - - - +---+ | _______________ _______________ | |/ IP/MPLS Net. \ / MPLS-TP Net. \| +-----------------+-----------------+ ^ \_______________/ \_______________/ PW emulation PWs: |-------------MS-PW-------------| |---------------|---------------| ^ ^ PW segments Nodes: +++++ +++++ + 1 +----+- - - - - - - - - - - - - - - -+----+ 7 + +++++ | | +++++ CE +++++ +++++ +++++ +++++ +++++ CE + 2 +...+ 3 +---+ 4 +...+ 5 +...+ 6 + +++++ +++++ +++++ +++++ +++++ LER LSR LER LSR LER T-PE S-PE T-PE Border Node - Multisegment Pseudowire - Networks and PWs view Figure 3 The following figure illustrates the stacking relationship among the technology layers and OAM relationship among the networks: Martinotti, et al. Expires May 13, 2010 [Page 8] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 Layers: |--------+--------------CLI--------------+--------| |--SRV--| |---------PW---+--------------| |--SRV--| |-----LSP-----| |-----LSP-----| |-ETH-| |-ETH-| |-ETH-| |-ETH-| |-PHY-| |-PHY-| |-PHY-| |-PHY-| OAM: (3) >-------------O-------------< MS-PW (2) >-----------< >-----------< LSP (1) >--< >...< >---< >...< >...< >--< PHY Nodes: +++++ +++++ +++++ +++++ +++++ +++++ +++++ + 1 +--+ 2 +...+ 3 +---+ 4 +...+ 5 +...+ 6 +--+ 7 + +++++ +++++ +++++ +++++ +++++ +++++ +++++ CE LER LSR LER LSR LER CE Border Node - Multisegment Pseudowire - Layers and OAM view Figure 4 Several levels of OAM are possible, a subset of them is shown in the previous figure, however these are not comprehensive, any subset of them MAY be configured in a network. A brief description of the different levels is provided: (3) Edge-to-Edge MPLS/MPLS-TP OAM on partitioned network (at PW level) (2) Edge-to-Edge MPLS/MPLS-TP OAM on partitioned network (at LSP level) (1) Physical level OAM (MAY be of several kind) Open Points: o Interworking between LSP OAM (2) and MS-PW OAM (3) is still to be cleared/defined o Edge-to-Edge MS-PW OAM (3) must be configured on different subnetworks Martinotti, et al. Expires May 13, 2010 [Page 9] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 7.1.2. LSP stitching The following figure illustrates the functional interworking among the networks: Networks: Customer Network +---+ - - - - - - - - - - - - - - - - - +---+ | _______________ _______________ | |/ IP/MPLS Net. \ / MPLS-TP Net. \| +-----------------+-----------------+ ^ \_______________/ \_______________/ PW emulation PWs: |-------------SS-PW-------------| Nodes: +++++ +++++ + 1 +----+- - - - - - - - - - - - - - - -+----+ 9 + +++++ | | +++++ CE +++++ +++++ +++++ +++++ +++++ CE + 2 +...+ 3 +---+ 4 +...+ 5 +...+ 6 + +++++ +++++ +++++ +++++ +++++ LER LSR LER LSR LER PE PE Border Node - LSP stitching - Networks and PWs view Figure 5 The following figure illustrates the stacking relationship among the technology layers and OAM relationship among the networks: Martinotti, et al. Expires May 13, 2010 [Page 10] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 Layers: |--------+--------------CLI--------------+--------| |--SRV--| |--------------PW-------------| |--SRV--| |-------------<->-LSP---------| |-ETH-| |-ETH-| |-ETH-| |-ETH-| |-PHY-| |-PHY-| |-PHY-| |-PHY-| OAM: (4) >---------------------------< PW (3) >-------------O-------------< LSP (2) >-----------< >-----------< TCM (1) >--< >...< >---< >...< >...< >--< PHY Nodes: +++++ +++++ +++++ +++++ +++++ +++++ +++++ + 1 +--+ 2 +...+ 3 +---+ 4 +...+ 5 +...+ 6 +--+ 7 + +++++ +++++ +++++ +++++ +++++ +++++ +++++ CE LER LSR LER LSR LER CE Border Node - LSP stitching - Layers and OAM view Figure 6 Note: in this case a SS-PW extends over the subnetworks as the stitched LSP does. TCM can be used to monitor the LSP segments. Several levels of OAM are possible, a subset of them is shown in the previous figure, however these are not comprehensive, any subset of them MAY be configured in a network. A brief description of the different levels is provided: (4) Edge-to-Edge MPLS/MPLS-TP OAM on partitioned network (at PW level) (3) Edge-to-Edge MPLS/MPLS-TP OAM on partitioned network (at LSP level) (2) Edge-to-Edge MPLS/MPLS-TP OAM on partitioned network (at TCM level) (1) Physical level OAM (MAY be of several kind) Open Points: o Edge-to-Edge LSP OAM (3) must be configured on different subnetworks Martinotti, et al. Expires May 13, 2010 [Page 11] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 o Edge-to-Edge PW OAM (4) must be configured on different subnetworks o Interworking between TCM OAM (2) and LSP OAM (3) is still to be cleared/defined o Interaction between IP/MPLS and MPLS-TP CPs is still to be cleared/defined 7.2. Border Link Main features to be taken into account: o MultiSegment Pseudowire o LSP Stitching o Interaction between DP of IP/MPLS and DP of MPLS-TP o Interaction between CP of IP/MPLS and CP of MPLS-TP o No interaction between MP of IP/MPLS and MP of MPLS-TP o Possible PHP handling of client MPLS Layer 7.2.1. Multisegment Pseudowire The following figure illustrates the functional interworking among the networks: Martinotti, et al. Expires May 13, 2010 [Page 12] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 Networks: Customer Network +---+ - - - - - - - - - - - - - - - - - -+---+ | ___________ ______________ | |/IP/MPLS N. \ / MPLS-TP N. \| +-------------+-----+----------------+ ^ \___________/ \______________/ PW emulation PWs: |------------MS-PW--------------| |-----------|-----|-------------| ^ ^ ^ PW segments Nodes: +++++ +++++ + 1 +----+- - - - - - - - - - - - - - - -+----+ 6 + +++++ | | +++++ CE +++++ +++++ +++++ +++++ CE + 2 +.....+ 3 +-----+ 4 +.......+ 5 + +++++ +++++ +++++ +++++ LER LER LER LER T-PE S-PE S-PE T-PE Border Link - Multisegment Pseudowire - Networks view Figure 7 The following figure illustrates the stacking relationship among the technology layers and OAM relationship among the networks: Martinotti, et al. Expires May 13, 2010 [Page 13] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 Layers: |--------+-------------CLI---------------+--------| |--SRV--| |--------+----PW---+----------| |--SRV--| |--LSP--| |--LSP--| |---LSP---| |- ETH -| |--ETH--| |- -ETH- -| |- PHY -| |--PHY--| |- -PHY- -| OAM: (3) >-------O---------O---------< MS-PW (2) >-----< >-----< >-------< LSP (1) >--< >.....< >-----< >.......< >--< PHY Nodes: +++++ +++++ +++++ +++++ +++++ +++++ + 1 +--+ 2 +.....+ 3 +-----+ 4 +.......+ 5 +--+ 6 + +++++ +++++ +++++ +++++ +++++ +++++ CE LER LER LER LER CE Border Link - Multisegment Pseudowire - Layers and OAM view Figure 8 Several levels of OAM are possible, a subset of them is shown in the previous figure, however these are not comprehensive, any subset of them MAY be configured in a network. A brief description of the different levels is provided: (3) Edge-to-Edge MPLS/MPLS-TP OAM on partitioned network (at PW level) (2) Edge-to-Edge MPLS/MPLS-TP OAM on partitioned network (at LSP level) (1) Physical level OAM (MAY be of several kinds) Open Points: o Interworking between LSP OAM (2) and MS-PW OAM (3) is still to be cleared/defined o LSP between Node 3 and 4 could be avoided, however in this case PW over Ethernet should be specified. o Edge-to-Edge MS-PW OAM (3) must be configured on different subnetworks Martinotti, et al. Expires May 13, 2010 [Page 14] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 7.2.2. LSP stitching The following figure illustrates the functional interworking among the networks: Networks: Customer Network +---+ - - - - - - - - - - - - - - - - - -+---+ | ___________ ______________ | |/IP/MPLS N. \ / MPLS-TP N. \| +-------------+-----+----------------+ ^ \___________/ \______________/ PW emulation PWs: |------------SS-PW--------------| Nodes: +++++ +++++ + 1 +----+- - - - - - - - - - - - - - - -+----+ 6 + +++++ | | +++++ CE +++++ +++++ +++++ +++++ CE + 2 +.....+ 3 +-----+ 4 +.......+ 5 + +++++ +++++ +++++ +++++ LER LER LER LER PE PE Border Link - LSP stitching - Networks view Figure 9 The following figure illustrates the stacking relationship among the technology layers and OAM relationship among the networks: Martinotti, et al. Expires May 13, 2010 [Page 15] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 Layers: |--------+-------------CLI---------------+--------| |--SRV--| |-------------PW--------------| |--SRV--| |-------<->--LSP--<->---------| |- ETH -| |--ETH--| |- -ETH- -| |- PHY -| |--PHY--| |- -PHY- -| OAM: (4) >---------------------------< SS-PW (3) >-------O---------O---------< LSP (2) >-----< >-----< >-------< TCM (1) >--< >.....< >-----< >.......< >--< PHY Nodes: +++++ +++++ +++++ +++++ +++++ +++++ + 1 +--+ 2 +.....+ 3 +-----+ 4 +.......+ 5 +--+ 6 + +++++ +++++ +++++ +++++ +++++ +++++ CE LER LER LER LER CE Border Link - LSP stitching - Layers and OAM view Figure 10 Note: in this case a SS-PW extends over the subnetworks as the stitched LSP does. TCM can be used to monitor the LSP segments. Several levels of OAM are possible, a subset of them is shown in the previous figure, however these are not comprehensive, any subset of them MAY be configured in a network. A brief description of the different levels is provided: (4) Edge-to-Edge MPLS/MPLS-TP OAM on partitioned network (at PW level) (3) Edge-to-Edge MPLS/MPLS-TP OAM on partitioned network (at LSP level) (2) Edge-to-Edge MPLS/MPLS-TP OAM on partitioned network (at TCM level) (1) Physical level OAM (MAY be of several kinds) Open Points: o Edge-to-Edge LSP OAM (3) must be configured on different subnetworks o Edge-to-Edge PW OAM (4) must be configured on different subnetworks Martinotti, et al. Expires May 13, 2010 [Page 16] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 o Interworking between TCM OAM (2) and LSP OAM (3) is still to be cleared/defined o Interaction between IP/MPLS and MPLS-TP CPs is still to be cleared/defined 8. Conclusions This document has illustrated some deployment scenarios where a partitioning relationship is in place between MPLS-TP and IP/MPLS. Where open points and open issues still appear, the reader is invited to contribute to their resolution. The following scenarios is recommended: Network Partitioning Border Link, using Multisegment Pseudowire 9. Contributors Alessandro Capello (Telecom Italia). 10. Acknowledgements The authors gratefully acknowledge the input of Attila Takacs. 11. IANA Considerations This memo includes no request to IANA. 12. Security Considerations This document does not introduce any additional security aspects beyond those applicable to PWE3 and MPLS. 13. References 13.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Martinotti, et al. Expires May 13, 2010 [Page 17] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 13.2. Informative References [ITU-T G.805] "Generic functional architecture of transport networks", ID ITU-T G.805, March 2000. [RFC 3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol Label Switching Architecture", RFC 3031, January 2001. [RFC 5654] Niven-Jenkins, B., Brungard, D., and M. Betts, "Requirements of an MPLS Transport Profile", RFC 5654, September 2009. [draft mpls-tp framework] Bocci, M., Bryant, S., and L. Levrau, "A Framework for MPLS in Transport Networks", ID draft-ietf-mpls-tp-framework-06, October 2009. [draft mpls-tp oam requirements] Vigoureux, M., Ward, D., and M. Betts, "Requirements for OAM in MPLS Transport Networks", ID draft-ietf-mpls-tp-oam-requirements-03, August 2009. Appendix A. Additional Stuff This becomes an Appendix. Authors' Addresses Riccardo Martinotti (editor) Ericsson Via A. Negrone 1/A Genova - Sestri Ponente 16153 Italy Email: riccardo.martinotti@ericsson.com Martinotti, et al. Expires May 13, 2010 [Page 18] Internet-Draft draft-martinotti-mpls-tp-iw-partition-00 November 2009 Diego Caviglia Ericsson Via A. Negrone 1/A Genova - Sestri Ponente 16153 Italy Email: diego.caviglia@ericsson.com Nurit Sprecher Nokia Siemens Networks 3 Hanagar St. Neve Ne'eman B Hod Hasharon 45241 Israel Email: nurit.sprecher@nsn.com Alessandro D'Alessandro Telecom Italia Via Reiss Romoli, 274 Torino 10148 Italy Email: alessandro.dalessandro@telecomitalia.it Martinotti, et al. Expires May 13, 2010 [Page 19]