Movatterモバイル変換

Internet Engineering Task Force (IETF)                          M. BocciRequest for Comments: 6215                                     L. LevrauUpdates:5921                                             Alcatel-LucentCategory: Informational                                         D. FrostISSN: 2070-1721                                                    Cisco                                                              April 2011MPLS Transport Profile User-to-Networkand Network-to-Network InterfacesAbstract   The framework for MPLS in transport networks (RFC 5921) provides   reference models for the MPLS Transport Profile (MPLS-TP) Transport   Service Interfaces, which are a User-to-Network Interface (UNI), and   a Network-to-Network Interface (NNI).  This document updates those   reference models to show detailed reference points for these   interfaces, along with further clarification of the functional   architecture of MPLS-TP at a UNI and NNI.   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 Pseudowire Emulation Edge-to-Edge   (PWE3) architectures to support the capabilities and functionalities   of a packet transport network as defined by the ITU-T.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; seeSection 2 of RFC 5741.   Information about the current status of this document, any errata,   and how to provide feedback on it may be obtained athttp://www.rfc-editor.org/info/rfc6215.Bocci, et al.                 Informational                     [Page 1]

RFC 6215                   MPLS-TP UNI and NNI                April 2011Copyright Notice   Copyright (c) 2011 IETF Trust and the persons identified as the   document authors.  All rights reserved.   This document is subject toBCP 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.1.  Introduction   The framework for MPLS in transport networks [RFC5921] provides   reference models for the MPLS Transport Profile (MPLS-TP) Transport   Service Interfaces, which are a User-to-Network Interface (UNI) and a   Network-to-Network Interface (NNI).  This document updates those   reference models to show detailed reference points for these   interfaces, along with further clarification of the functional   architecture of MPLS-TP at a UNI and NNI.   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 as   defined by the ITU-T.1.1.  Updates to the MPLS-TP UNI and NNI   The Transport Service Interfaces for MPLS-TP are defined inSection3.4.3 of [RFC5921].  These definitions are illustrated by showing   MPLS-TP Provider Edges (PEs) containing a UNI and an NNI.  The   figures illustrate the UNI and the NNI as a span.  However, it is   convention to illustrate these interfaces as reference points.   Furthermore, in the case of a UNI, it is useful to illustrate the   distribution of UNI functions between the Customer Edge (CE) side and   the PE side of the UNI, i.e., the UNI-C (User-to-User Interface,   Client side) and UNI-N (User-to-Network Interface, Network side), in   order to show their relationship to one another.Bocci, et al.                 Informational                     [Page 2]

RFC 6215                   MPLS-TP UNI and NNI                April 2011   This document provides updated illustrations of the MPLS-TP UNI and   MPLS-TP NNI to show these additional details.  These illustrations   obsolete the corresponding ones in [RFC5921].  This document also   defines additional terminology referenced in the illustrations.  No   other updates are made by this document.   Awareness of the Transport Service layer need exist only at PE nodes,   and so only these nodes are illustrated in the figures.  MPLS-TP   Provider (P) nodes need have no awareness of this layer.  Both PE and   P nodes participate in the Transport Path layer.  A PE terminates   (i.e., is a Label Edge Router (LER) with respect to) the transport   paths it supports, and is responsible for multiplexing and   demultiplexing of Transport Service Instance traffic over such   transport paths.1.2.  Terminology and Abbreviations   The terminology and abbreviations of [RFC5921] apply.   The following additional terminology is used in this document.   Term  Definition   ----- ---------------------------------------   CP    Control Plane   NNI   Network-to-Network Interface   TSI   Transport Service Instance   UNI   User-to-Network Interface   UNI-C User-to-Network Interface, Client side   UNI-N User-to-Network Interface, Network side   Transport Service Instance:  A single logical point-to-point      connection at the Transport Service layer between the ingress PE      providing a packet transport service to a CE, and the      corresponding egress PE to which the peer CE is attached.2.  MPLS-TP User-to-Network Interface   The MPLS-TP User-to-Network Interface (UNI) is illustrated in   Figure 1.  This figure obsoletes Figure 3 of [RFC5921].  Note that   the term "MPLS-TP UNI" is to be interpreted as a UNI to an MPLS-TP   network and does not refer to the protocol transiting the UNI.  The   UNI for a particular client flow may involve signaling between the CE   and PE.  If signaling is used, it may traverse the same attachment   circuit that supports the client flow.Bocci, et al.                 Informational                     [Page 3]

RFC 6215                   MPLS-TP UNI and NNI                April 2011                       UNI                        :                             MPLS-TP    :<-- UNI-C -->:     :     :<-- UNI-N ->:          Network <----->    :  function   :     :     :  function  :   ---------------      :      ------------:--------------------    :             |     :     |            :   Transport        |    :             |     V     |    Client  :     Path           |    :             |           |   Service  :   Mux/Demux        |    :             |           |   Control  :      --            |    : ----------  |           |  ----------:     |  |  Transport|    :|          | |           | |          |     |  |    Path   |    :|Signaling |_|___________|_|Signaling |     |  |    --------->    :|Controller| |           | |Controller|     |  |   |    : ----------  |           |  ----------      |  |    --------->    :      :......|...........|......:     :     |  |           |    :             |  Control  |            :     |  |  Transport|    :             |  Channel  |            :     |  |    Path   |    :             |           |            :     |  |    --------->    :             |           |            :     |  |  -+----------->TSI    :             |           |  Transport :     |  | |  --------->    :             |  Client   |   Service  :     |  | |         |    :             |  Traffic  |  Data Plane:     |  | |         |    : ----------  |  Flows    |  --------------  |  | |Transport|    :| Client   |-|-----------|-|Client/Service|-|  |-   Path   |    :| Traffic  |=|===========|=|    Traffic   | |  |    --------->    :|Processing| |           | |  Processing  |=|  |===+===========>TSI    : ----------  |           |  --------------  |  |    --------->    :      |______|___________|______|     :     |  |           |    :             | Data Link |            :     |  |           |    :             |           |            :      --            |    :             |           |            :          Transport |    :             |           |            :             Path   |    :             |           |            :          Data Plane|   ---------------             ---------------------------------   Customer Edge Node              MPLS-TP Provider Edge NodeNote: The client service control plane may be a control protocol      belonging to the native service, or GMPLS.             Figure 1: UNI between CE Node and MPLS-TP PE NodeBocci, et al.                 Informational                     [Page 4]

RFC 6215                   MPLS-TP UNI and NNI                April 20113.  MPLS-TP Network-to-Network Interface   The MPLS-TP Network-to-Network Interface (NNI) is illustrated in   Figure 2.  This figure obsoletes Figure 5 of [RFC5921].  The NNI for   a particular Transport Service Instance may involve signaling between   the two PEs.  If signaling is used, it may traverse the same data-   link that supports the service instance.                                  NNI                :<--- NNI --->:    :     :<--- NNI ---->:                :  Function   :    :     :   Function   :    ---------------------------    :      --------------------------   |            :  Transport   |   :     |   Transport  :           |   |            :  Service CP  |   V     |   Service CP :           |   |            :  ----------  |Signaling|  ----------  :           |   |            : |Signaling |_| _______ |_|Signaling | :           |   |            : |Controller| |         | |Controller| :           |   |            :  ----------  |         |  ----------  :           |   |            :       :....... Control .......:       :           |   |            :              | Channel |              :           |   |   -        :   Transport  |         | Transport    :        -  |   |  | |       :     Path CP  |         |  Path CP     :       | | |   |  | |       :  ----------  |Signaling|  ----------  :       | | | -----| |       : |Signaling |_| _______ |_|Signaling | :       | |----- ---+-| |       : |Controller| |         | |Controller| :       | |-+--- -----| |       :  ----------  |         |  ----------  :       | |-----   |  | |       :       :....... Control .......:       :       | | |   |  | |       :              | Channel |              :       | | |   |  | |  Transport Path      |         |       Transport Path | | |   |  | | /  mux/demux   \     |         |      /  mux/demux   \| | |   |  | |/      :         \--  |         |  -- /        :       | | |   |  | |   ----------    |  | |Transport| |  |    ----------   | | |   |  | |--|Transport |---|  | |  Path   | |  |---|Transport |--| | | -----| |  | Service  |   |  |-------------|  |   | Service  |  | |----- TSI+=| |==|Processing|===|  |<+===TSI===+>|  |===|Processing|==| |=+TSI -----| |   ----------    |  |-------------|  |    ----------   | |-----   |  | |       :         |  | |         | |  |         :       | | |   |  | |       :         |  | |         | |  |         :       | | |   |   -        :          --  |         |  --          :        -  |   |            :              |         |              :           |   |     Transport Path        |         |      Transport Path      |   |       Data Plane                    |        Data Plane        |    ---------------------------           --------------------------         MPLS-TP Provider                        MPLS-TP Provider           Edge Node A                             Edge Node B                  Figure 2: NNI between MPLS-TP PE NodesBocci, et al.                 Informational                     [Page 5]

RFC 6215                   MPLS-TP UNI and NNI                April 20114.  Security Considerations   The security considerations of [RFC5921] apply.  The updated   reference models provided by this document introduce no new security   considerations.5.  Acknowledgements   The editors wish to thank the following for their contribution to   this document:   o  Eve Varma   o  Dieter Beller   o  Lou Berger   o  Stewart Bryant   o  Italo Busi   o  The experts of ITU-T Study Group 15 and the IETF MPLS and PWE3      working groups.6.  Normative References   [RFC5921]  Bocci, M., Bryant, S., Frost, D., Levrau, L., and L.              Berger, "A Framework for MPLS in Transport Networks",RFC 5921, July 2010.Authors' Addresses   Matthew Bocci   Alcatel-Lucent   EMail: matthew.bocci@alcatel-lucent.com   Lieven Levrau   Alcatel-Lucent   EMail: lieven.levrau@alcatel-lucent.com   Dan Frost   Cisco   EMail: danfrost@cisco.comBocci, et al.                 Informational                     [Page 6]