Protocol Independent Multicast Equal-Cost Multipath (ECMP) Redirect
RFC 6754
| Document | Type |
RFC - Proposed Standard
(October 2012; No errata)
Updated by RFC 8736
Was draft-ietf-pim-ecmp (pim WG)
|
|
|---|---|---|---|
| Last updated | 2015-10-14 | ||
| Replaces | draft-hou-pim-ecmp | ||
| Stream | IETF | ||
| Formats | plain text html pdf htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | WG Document | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 6754 (Proposed Standard) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Adrian Farrel | ||
| IESG note | Mike McBride (mmcbride7@gmail.com) is the document shepherd. | ||
| Send notices to | (None) | ||
Internet Engineering Task Force (IETF) Y. Cai
Request for Comments: 6754 Microsoft
Category: Standards Track L. Wei
ISSN: 2070-1721 H. Ou
Cisco Systems, Inc.
V. Arya
S. Jethwani
DIRECTV Inc.
October 2012
Protocol Independent Multicast Equal-Cost Multipath (ECMP) Redirect
Abstract
A Protocol Independent Multicast (PIM) router uses the Reverse Path
Forwarding (RPF) procedure to select an upstream interface and router
in order to build forwarding state. When there are equal-cost
multipaths (ECMPs), existing implementations often use hash
algorithms to select a path. Such algorithms do not allow the spread
of traffic among the ECMPs according to administrative metrics. This
usually leads to inefficient or ineffective use of network resources.
This document introduces the ECMP Redirect, a mechanism to improve
the RPF procedure over ECMPs. It allows ECMP selection to be based
on administratively selected metrics, such as data transmission
delays, path preferences, and routing metrics.
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 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6754.
Cai, et al. Standards Track [Page 1]
RFC 6754 PIMv2 ECMP Redirect October 2012
Copyright Notice
Copyright (c) 2012 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
(http://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. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Protocol Specification . . . . . . . . . . . . . . . . . . . . 6
5.1. Sending ECMP Redirect . . . . . . . . . . . . . . . . . . 6
5.2. Receiving ECMP Redirect . . . . . . . . . . . . . . . . . 7
5.3. Transient State . . . . . . . . . . . . . . . . . . . . . 7
5.4. Interoperability . . . . . . . . . . . . . . . . . . . . . 8
5.5. Packet Format . . . . . . . . . . . . . . . . . . . . . . 8
5.5.1. PIM ECMP Redirect Hello Option . . . . . . . . . . . . 8
5.5.2. PIM ECMP Redirect Format . . . . . . . . . . . . . . . 9
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
7. Security Considerations . . . . . . . . . . . . . . . . . . . 10
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
9.1. Normative References . . . . . . . . . . . . . . . . . . . 11
9.2. Informative References . . . . . . . . . . . . . . . . . . 11
Cai, et al. Standards Track [Page 2]
RFC 6754 PIMv2 ECMP Redirect October 2012
1. Introduction
A PIM router uses the RPF procedure to select an upstream interface
and a PIM neighbor on that interface to build forwarding state. When
there are equal-cost multipaths (ECMPs) upstream, existing
implementations often use hash algorithms to select a path. Such
algorithms do not allow the spread of traffic among the ECMP
according to administrative metrics. This usually leads to
inefficient or ineffective use of network resources. This document
introduces the ECMP Redirect, a mechanism to improve the RPF
procedure over ECMP. It allows ECMP selection to be based on
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