Synonymous Flow Label Framework
RFC 8957

Document Type RFC - Proposed Standard (January 2021; No errata)
Authors Stewart Bryant  , Mach Chen  , George Swallow  , Siva Sivabalan  , Greg Mirsky 
Last updated 2021-01-22
Replaces draft-bryant-mpls-sfl-framework
Stream Internent Engineering Task Force (IETF)
Formats plain text html xml pdf htmlized (tools) htmlized bibtex
Reviews
Stream WG state Submitted to IESG for Publication
Document shepherd Tarek Saad
Shepherd write-up Show (last changed 2020-09-16)
IESG IESG state RFC 8957 (Proposed Standard)
Action Holders
(None)
Consensus Boilerplate Yes
Telechat date
Responsible AD Deborah Brungard
Send notices to Tarek Saad <tsaad.net@gmail.com>
IANA IANA review state IANA OK - No Actions Needed
IANA action state No IANA Actions


Internet Engineering Task Force (IETF)                         S. Bryant
Request for Comments: 8957                   Futurewei Technologies Inc.
Category: Standards Track                                        M. Chen
ISSN: 2070-1721                                                   Huawei
                                                              G. Swallow
                                               Southend Technical Center
                                                            S. Sivabalan
                                                       Ciena Corporation
                                                               G. Mirsky
                                                               ZTE Corp.
                                                            January 2021

                    Synonymous Flow Label Framework

Abstract

   RFC 8372 ("MPLS Flow Identification Considerations") describes the
   requirement for introducing flow identities within the MPLS
   architecture.  This document describes a method of accomplishing this
   by using a technique called "Synonymous Flow Labels" in which labels
   that mimic the behavior of other labels provide the identification
   service.  These identifiers can be used to trigger per-flow
   operations on the packet at the receiving label switching router.

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/rfc8957.

Copyright Notice

   Copyright (c) 2021 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
   2.  Requirements Language
   3.  Synonymous Flow Labels
   4.  User Service Traffic in the Data Plane
     4.1.  Application Label Present
       4.1.1.  Setting TTL and the Traffic Class Bits
     4.2.  Single-Label Stack
       4.2.1.  Setting TTL and the Traffic Class Bits
     4.3.  Aggregation of SFL Actions
   5.  Equal-Cost Multipath Considerations
   6.  Privacy Considerations
   7.  Security Considerations
   8.  IANA Considerations
   9.  References
     9.1.  Normative References
     9.2.  Informative References
   Contributors
   Authors' Addresses

1.  Introduction

   [RFC8372] ("MPLS Flow Identification Considerations") describes the
   requirement for introducing flow identities within the MPLS
   architecture.  This document describes a method of providing the
   required identification by using a technique called "Synonymous Flow
   Labels (SFLs)" in which labels that mimic the behavior of other MPLS
   labels provide the identification service.  These identifiers can be
   used to trigger per-flow operations on the packet at the receiving
   label switching router.

2.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  Synonymous Flow Labels

   An SFL is defined to be a label that causes exactly the same behavior
   at the egress Label Edge Router (LER) as the label it replaces,
   except that it also causes one or more additional actions that have
   been previously agreed between the peer LERs to be executed on the
   packet.  There are many possible additional actions, such as
   measuring the number of received packets in a flow, triggering an IP
   Flow Information Export (IPFIX) [RFC7011] capture, triggering other
   types of deep packet inspection, or identifying the packet source.
   For example, in a Performance Monitoring (PM) application, the agreed
   action could be recording the receipt of the packet by incrementing a
   packet counter.  This is a natural action in many MPLS
   implementations, and where supported, this permits the implementation
   of high-quality packet loss measurement without any change to the
Show full document text