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 | IETF | ||
| Formats | plain text html xml pdf 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
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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
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