Explicit Congestion Notification (ECN) and Congestion Feedback Using the Network Service Header (NSH)
draft-ietf-sfc-nsh-ecn-support-04
INTERNET-DRAFT Donald Eastlake
Intended status: Proposed Standard Futurewei Technologies
Bob Briscoe
Independent
Andrew Malis
Independent
Expires: June 5, 2021 December 6, 2020
Explicit Congestion Notification (ECN) and Congestion Feedback
Using the Network Service Header (NSH)
<draft-ietf-sfc-nsh-ecn-support-04.txt>
Abstract
Explicit congestion notification (ECN) allows a forwarding element to
notify downstream devices of the onset of congestion without having
to drop packets. Coupled with a means to feed information about
congestion back to upstream nodes, this can improve network
efficiency through better congestion control, frequently without
packet drops. This document specifies ECN and congestion feedback
support within a Service Function Chaining (SFC) architecture domain
through use of the Network Service Header (NSH, RFC 8300) and IP Flow
Information Export (IPFIX,
draft-ietf-tsvwg-tunnel-congestion-feedback).
Status of This Memo
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D. Eastlake, B. Briscoe, & A. Malis [Page 1]
INTERNET-DRAFT NSH ECN & Congestion Feedback
Table of Contents
1. Introduction............................................3
1.1 NSH Background.........................................3
1.2 ECN Background.........................................5
1.3 Tunnel Congestion Feedback Background..................5
1.4 Conventions Used in This Document......................7
2. The NSH ECN Field.......................................8
3. ECN Support in the NSH.................................10
3.1 At The Ingress........................................11
3.2 At Transit Nodes......................................12
3.2.1 At NSH Transit Nodes................................12
3.2.2 At an SF/Proxy......................................13
3.2.3 At Other Forwarding Nodes...........................13
3.3 At Exit/Egress........................................13
3.4 Conservation of Packets...............................14
4. Tunnel Congestion Feedback Support.....................15
5. IANA Considerations....................................16
5.1 SFC NSH Header ECN Bits...............................16
5.2 IPFIX Information Element ID..........................16
6. Security Considerations................................17
7. Acknowledgements.......................................17
Normative References......................................18
Informative References....................................18
Authors' Addresses........................................20
D. Eastlake, B. Briscoe, & A. Malis [Page 2]
INTERNET-DRAFT NSH ECN & Congestion Feedback
1. Introduction
Explicit congestion notification (ECN [RFC3168]) allows a forwarding
element to notify downstream devices of the onset of congestion
without having to drop packets. Coupled with a means to feed
information about congestion back to upstream nodes, this can improve
network efficiency through better congestion control, frequently
without packet drops. This document specifies ECN and congestion
feedback support within a Service Function Chaining (SFC [RFC7665])
architecture domain through use of the Network Service Header (NSH
[RFC8300]) and IP Flow Information Export (IPFIX
[TunnelCongFeedback]).
It requires that all ingress and egress nodes of the SFC domain
implement ECN. While congestion management will be the most effective
if all interior nodes of the SFC domain implement ECN, some benefit
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