Controlled Return Path for Service Function Chain (SFC) OAM
draft-ao-sfc-oam-return-path-specified-05

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SFC WG                                                             T. Ao
Internet-Draft                                    Individual contributor
Intended status: Standards Track                               G. Mirsky
Expires: June 3, 2020                                          ZTE Corp.
                                                                 Z. Chen
                                                           China Telecom
                                                        December 1, 2019

      Controlled Return Path for Service Function Chain (SFC) OAM
               draft-ao-sfc-oam-return-path-specified-05

Abstract

   This document defines an extension to the Service Function Chain
   (SFC) Operation, Administration and Maintenance (OAM) that enables
   control of the Echo Reply return path directing it over a Reverse
   Service Function Path.  Enforcing the specific return path can be
   used to verify the bidirectional connectivity of SFC and increase the
   robustness of SFC OAM.

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
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   Internet-Drafts are draft documents valid for a maximum of six months
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on June 3, 2020.

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
   carefully, as they describe your rights and restrictions with respect

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   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.  Conventions used in this document . . . . . . . . . . . . . .   3
     2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   3.  Extension . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  SFC Reply Path TLV  . . . . . . . . . . . . . . . . . . . . .   4
   5.  Theory of Operation . . . . . . . . . . . . . . . . . . . . .   5
     5.1.  Bi-directional SFC Case . . . . . . . . . . . . . . . . .   5
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
     7.1.  SFC Return Path Type  . . . . . . . . . . . . . . . . . .   6
     7.2.  New Return Codes  . . . . . . . . . . . . . . . . . . . .   6
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   While Service Function Chain (SFC) Echo Request, defined in
   [I-D.ietf-sfc-multi-layer-oam], always traverses the SFC it directed
   to, the corresponding Echo Reply is sent over IP network
   [I-D.ietf-sfc-multi-layer-oam].  There are scenarios when it is
   beneficial to direct the responder to use a path other than the IP
   network.  This document extends Service Function Chain (SFC)
   Operation, Administration and Maintenance (OAM) by enabling control
   of the Echo Reply return path to be directed over a Reply Service
   Function Path (SFP).  This document defines a new Type-Length-Value
   (TLV), Reply Service Function Path TLV, for Reply via Specified Path
   mode of SFC Echo Reply (Section 4).

   The Reply Service Function Path TLV can provide an efficient
   mechanism to test SFCs, such as bidirectional and hybrid SFC, as
   defined in Section 2.2 [RFC7665].  For example, it allows an operator
   to test both directions of the bidirectional or hybrid SFP with a
   single SFC Echo Request/Echo Reply operation.

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2.  Conventions used in this document