An MPLS-Based Forwarding Plane for Service Function Chaining
draft-ietf-mpls-sfc-07

Document Type Active Internet-Draft (mpls WG)
Last updated 2019-05-01 (latest revision 2019-03-07)
Replaces draft-farrel-mpls-sfc
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MPLS Working Group                                             A. Farrel
Internet-Draft                                        Old Dog Consulting
Intended status: Standards Track                               S. Bryant
Expires: September 8, 2019                                        Huawei
                                                                J. Drake
                                                        Juniper Networks
                                                           March 7, 2019

      An MPLS-Based Forwarding Plane for Service Function Chaining
                         draft-ietf-mpls-sfc-07

Abstract

   This document describes how Service Function Chaining (SFC) can be
   achieved in an MPLS network by means of a logical representation of
   the Network Service Header (NSH) in an MPLS label stack.  That is,
   the NSH is not used, but the fields of the NSH are mapped to fields
   in the MPLS label stack.  It does not deprecate or replace the NSH,
   but acknowledges that there may be a need for an interim deployment
   of SFC functionality in brownfield networks.

Status of This Memo

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   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on September 8, 2019.

Copyright Notice

   Copyright (c) 2019 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
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents

Farrel, et al.          Expires September 8, 2019               [Page 1]
Internet-Draft                  MPLS SFC                      March 2019

   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   4
   3.  Choice of Data Plane SPI/SI Representation  . . . . . . . . .   4
   4.  Use Case Scenarios  . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  Label Swapping for Logical NSH  . . . . . . . . . . . . .   5
     4.2.  Hierarchical Encapsulation  . . . . . . . . . . . . . . .   5
     4.3.  Fine Control of Service Function Instances  . . . . . . .   5
     4.4.  Micro Chains and Label Stacking . . . . . . . . . . . . .   5
     4.5.  SFC and Segment Routing . . . . . . . . . . . . . . . . .   6
   5.  Basic Unit of Representation  . . . . . . . . . . . . . . . .   6
   6.  MPLS Label Swapping . . . . . . . . . . . . . . . . . . . . .   7
   7.  MPLS Label Stacking . . . . . . . . . . . . . . . . . . . . .  10
   8.  Mixed Mode Forwarding . . . . . . . . . . . . . . . . . . . .  11
   9.  A Note on Service Function Capabilities and SFC Proxies . . .  13
   10. Control Plane Considerations  . . . . . . . . . . . . . . . .  13
   11. Use of the Entropy Label  . . . . . . . . . . . . . . . . . .  14
   12. Metadata  . . . . . . . . . . . . . . . . . . . . . . . . . .  14
     12.1.  Indicating Metadata in User Data Packets . . . . . . . .  15
     12.2.  Inband Programming of Metadata . . . . . . . . . . . . .  17
       12.2.1.  Loss of Inband Metadata  . . . . . . . . . . . . . .  20
   13. Worked Examples . . . . . . . . . . . . . . . . . . . . . . .  21
   14. Implementation Notes  . . . . . . . . . . . . . . . . . . . .  24
   15. Security Considerations . . . . . . . . . . . . . . . . . . .  25
   16. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  27
   17. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  27
   18. Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  28
   19. References  . . . . . . . . . . . . . . . . . . . . . . . . .  28
     19.1.  Normative References . . . . . . . . . . . . . . . . . .  28
     19.2.  Informative References . . . . . . . . . . . . . . . . .  29
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  30

1.  Introduction
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