MPLS Transport Profile User-to-Network and Network-to-Network Interfaces
draft-bfl-mpls-tp-uni-nni-00

Abstract

The framework for MPLS in transport networks [RFC5921] (Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. Berger, “A Framework for MPLS in Transport Networks,” July 2010.) provides reference models for an MPLS-TP User-to-Network Interface (UNI), and an MPLS-TP 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.

This Informational Internet-Draft is aimed at achieving IETF Consensus before publication as an RFC and will be subjet 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 onsensus.]

Status of this Memo

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Table of Contents

1.  Introduction
    1.1.  Updates to the MPLS-TP UNI and NNI
    1.2.  Terminology and Abbreviations
2.  MPLS-TP User-to-Network Interface
3.  MPLS-TP Network-to-Network Interface
4.  IANA Considerations
5.  Security Considerations
6.  Acknowledgements
7.  Normative References
§  Authors' Addresses

1.  Introduction

The framework for MPLS in transport networks [RFC5921] (Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. Berger, “A Framework for MPLS in Transport Networks,” July 2010.) provides reference models for an MPLS-TP User-to-Network Interface (UNI), and an MPLS-TP 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 in Section 3.4.3 of [RFC5921] (Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. Berger, “A Framework for MPLS in Transport Networks,” July 2010.). These definitions are illustrated by showing MPLS-TP PEs containing a UNI and an NNI. The figures illustrate the UNI and the NNI as a span. However, it is more conventional 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 CE side and the PE side of the UNI (the UNI-C and UNI-N).

This document provides updated illustrations of the MPLS-TP UNI and MPLS-TP NNI to show these additional details. These illustrations are intended to obsolete the corresponding ones in [RFC5921] (Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. Berger, “A Framework for MPLS in Transport Networks,” July 2010.). This document also defines additional terminology referenced in the illustrations. No other updates are proposed by this document.

1.2.  Terminology and Abbreviations

The terminology and abbreviations of [RFC5921] (Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. Berger, “A Framework for MPLS in Transport Networks,” July 2010.) apply.

The following additional terminology is used in this document.

2.  MPLS-TP User-to-Network Interface

The MPLS-TP User-Network interface (UNI) is illustrated in Figure 1 (UNI Between CE Node and MPLS-TP PE Node). This figure obsoletes Figure 3 of [RFC5921] (Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. Berger, “A Framework for MPLS in Transport Networks,” July 2010.). Note that the term MPLS UNI is to be interpreted as a UNI to an MPLS-TP network and does not refer to the protocol transiting the UNI.

                       UNI
                        :                             MPLS-TP
    :<-- UNI-C -->:     :     :<-- UNI-N ->:          Network <----->
    :  function   :     :     :  function  :
     -------------      :      ------------:--------------------
    :             |     :     |            :   Transport        |
    :             |     V     |    Native  :     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 Node

Note: Native service control = Control plane belonging to the native
                               service and/or GMPLS UNI

3.  MPLS-TP Network-to-Network Interface

The MPLS-TP NNI is illustrated in Figure 1 (UNI Between CE Node and MPLS-TP PE Node). This figure obsoletes Figure 5 of [RFC5921] (Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. Berger, “A Framework for MPLS in Transport Networks,” July 2010.).

                                 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


Note: The Transport Service signaling controller is only required
      where the Transport Path terminates.

4.  IANA Considerations

This document makes no request of IANA.

Note to RFC Editor: this section may be removed on publication as an RFC.

5.  Security Considerations

The security considerations of RFC5921 apply. The updated reference models provided by this document introduce no new security considerations.

6.  Acknowledgements

The editors wish to thank the following for their contribution to this document:

• Eve Varma.
• Dieter Beller.
• Lou Berger.
• Stewart Bryant.
• Italo Busi.
• The participants of ITU-T Study Group 15.

7. Normative References

Authors' Addresses