PIM Designated Router Load Balancing
RFC 8775
| Document | Type |
RFC - Proposed Standard
(April 2020; No errata)
Was draft-ietf-pim-drlb (pim WG)
|
|
|---|---|---|---|
| Last updated | 2020-04-22 | ||
| Replaces | draft-hou-pim-drlb | ||
| Stream | IETF | ||
| Formats | plain text html xml pdf htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Mike McBride | ||
| Shepherd write-up | Show (last changed 2019-01-14) | ||
| IESG | IESG state | RFC 8775 (Proposed Standard) | |
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Alvaro Retana | ||
| Send notices to | aretana.ietf@gmail.com | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA action state | RFC-Ed-Ack | ||
Internet Engineering Task Force (IETF) Y. Cai
Request for Comments: 8775 H. Ou
Category: Standards Track Alibaba Group
ISSN: 2070-1721 S. Vallepalli
M. Mishra
S. Venaas
Cisco Systems, Inc.
A. Green
British Telecom
April 2020
PIM Designated Router Load Balancing
Abstract
On a multi-access network, one of the PIM-SM (PIM Sparse Mode)
routers is elected as a Designated Router. One of the
responsibilities of the Designated Router is to track local multicast
listeners and forward data to these listeners if the group is
operating in PIM-SM. This document specifies a modification to the
PIM-SM protocol that allows more than one of the PIM-SM routers to
take on this responsibility so that the forwarding load can be
distributed among multiple routers.
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/rfc8775.
Copyright Notice
Copyright (c) 2020 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. Terminology
3. Applicability
4. Functional Overview
4.1. GDR Candidates
5. Protocol Specification
5.1. Hash Mask and Hash Algorithm
5.2. Modulo Hash Algorithm
5.2.1. Modulo Hash Algorithm Examples
5.2.2. Limitations
5.3. PIM Hello Options
5.3.1. PIM DR Load-Balancing Capability (DRLB-Cap) Hello
Option
5.3.2. PIM DR Load-Balancing List (DRLB-List) Hello Option
5.4. PIM DR Operation
5.5. PIM GDR Candidate Operation
5.6. DRLB-List Hello Option Processing
5.7. PIM Assert Modification
5.8. Backward Compatibility
6. Operational Considerations
7. IANA Considerations
7.1. Initial Registry
7.2. Assignment of New Hash Algorithms
8. Security Considerations
9. References
9.1. Normative References
9.2. Informative References
Acknowledgements
Authors' Addresses
1. Introduction
On a multi-access LAN (such as an Ethernet) with one or more PIM-SM
(PIM Sparse Mode) [RFC7761] routers, one of the PIM-SM routers is
elected as a Designated Router (DR). The PIM DR has two
responsibilities in the PIM-SM protocol. For any active sources on a
LAN, the PIM DR is responsible for registering with the Rendezvous
Point (RP) if the group is operating in PIM-SM. Also, the PIM DR is
responsible for tracking local multicast listeners and forwarding
data to these listeners if the group is operating in PIM-SM.
Consider the following LAN in Figure 1:
(core networks)
| | |
| | |
R1 R2 R3
| | |
----(LAN)----
|
|
(many receivers)
Figure 1: LAN with Receivers
Assume R1 is elected as the DR. According to the PIM-SM protocol, R1
will be responsible for forwarding traffic to that LAN on behalf of
all local members. In addition to keeping track of membership
reports, R1 is also responsible for initiating the creation of source
and/or shared trees towards the senders or the RPs. The membership
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