Operating the Network Service Header (NSH) with Next Protocol "None"
RFC 8393

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Internet Engineering Task Force (IETF)                         A. Farrel
Request for Comments: 8393                                      J. Drake
Category: Standards Track                               Juniper Networks
ISSN: 2070-1721                                                 May 2018

  Operating the Network Service Header (NSH) with Next Protocol "None"

Abstract

   This document describes a network that supports Service Function
   Chaining (SFC) using the Network Service Header (NSH) with no payload
   data and carrying only metadata.  This is achieved by defining a new
   NSH "Next Protocol" type value of "None".

   This document illustrates some of the functions that may be achieved
   or enhanced by this mechanism, but it does not provide an exhaustive
   list of use cases, nor is it intended to be definitive about the
   functions it describes.  It is expected that other documents will
   describe specific use cases in more detail and will define the
   protocol mechanics for each use case.

Status of This Memo

   This is an Internet Standards Track document.

   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).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8393.

Farrel & Drake               Standards Track                    [Page 1]
RFC 8393                    NSH with No Data                    May 2018

Copyright Notice

   Copyright (c) 2018 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
   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   4
   3.  The Network Service Header  . . . . . . . . . . . . . . . . .   4
     3.1.  Next Protocol "None"  . . . . . . . . . . . . . . . . . .   4
   4.  Processing Rules  . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Backward Compatibility  . . . . . . . . . . . . . . . . . . .   5
   6.  Overview of Use Cases . . . . . . . . . . . . . . . . . . . .   6
     6.1.  Per-SFP Metadata  . . . . . . . . . . . . . . . . . . . .   6
     6.2.  Per-Flow Metadata . . . . . . . . . . . . . . . . . . . .   7
     6.3.  Coordination between SFC-Aware SFIs . . . . . . . . . . .   7
     6.4.  Operations, Administration, and Maintenance (OAM) . . . .   8
     6.5.  Control-Plane and Management-Plane Uses . . . . . . . . .   8
     6.6.  Non-applicable Use Cases  . . . . . . . . . . . . . . . .   9
   7.  Management and Congestion Control Considerations  . . . . . .   9
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  11
     10.2.  Informative References . . . . . . . . . . . . . . . . .  11
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  12
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

Farrel & Drake               Standards Track                    [Page 2]
RFC 8393                    NSH with No Data                    May 2018

1.  Introduction

   An architecture for Service Function Chaining (SFC) is presented in
   [RFC7665].  That architecture enables packets to be forwarded along
   Service Function Paths (SFPs) to pass through various Service
   Functions (SFs) that act on the packets.  Each packet is encapsulated
   with a Network Service Header (NSH) [RFC8300] that identifies the SFP
   that the packet travels along (by means of a Service Path Identifier
   -- SPI) and the hop (i.e., the next SF to be executed) along the SFP
   that the packet has reached (by means of a Service Index -- SI).  The
   SPI and SI are fields encoded in the NSH.

   Packets are classified at the SFC network ingress boundaries by
   classifiers (Section 4.4 of [RFC7665]) and have an NSH applied to