Advertising L2 Bundle Member Link Attributes in OSPF
draft-ketant-lsr-ospf-l2bundles-02
Link State Routing K. Talaulikar
Internet-Draft P. Psenak
Intended status: Standards Track Cisco Systems
Expires: January 1, 2021 June 30, 2020
Advertising L2 Bundle Member Link Attributes in OSPF
draft-ketant-lsr-ospf-l2bundles-02
Abstract
There are deployments where the Layer 3 interface on which OSPF
operates is a Layer 2 interface bundle. Existing OSPF advertisements
only support advertising link attributes of the Layer 3 interface.
If entities external to OSPF wish to control traffic flows on the
individual physical links which comprise the Layer 2 interface bundle
link attribute information about the bundle members is required.
This document introduces the ability for OSPF to advertise the link
attributes of layer 2 (L2) Bundle members.
Status of This Memo
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This Internet-Draft will expire on January 1, 2021.
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Internet-Draft OSPF L2 Bundles June 2020
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. L2 Bundle Member Attributes . . . . . . . . . . . . . . . . . 3
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
6.1. Normative References . . . . . . . . . . . . . . . . . . 7
6.2. Informational References . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
There are deployments where the Layer 3 interface on which an OSPF
adjacency is established is a Layer 2 interface bundle, for instance
a Link Aggregation Group (LAG) [IEEE802.1AX] . This reduces the
number of adjacencies which need to be maintained by the routing
protocol in cases where there are parallel links between the
neighbors. Entities external to OSPF such as Path Computation
Elements (PCE) [RFC4655] may wish to control traffic flows on
individual members of the underlying Layer 2 bundle. In order to do
so link attribute information about individual bundle members is
required. The protocol extensions defined in this document provide
the means to advertise this information.
This document introduces new sub-TLVs to advertise link attribute
information for each of the L2 Bundle members which comprise the
Layer 3 interface on which OSPF operates. Similar capabilities were
introduced in IS-IS via [RFC8668].
[RFC8665] and [RFC8666] introduced the adjacency segment identifier
(Adj-SID) link attribute for OSPFv2 and OSPFv3 respectively which can
be used as an instruction to forwarding to send traffic over a
specific link [RFC8402]. This document enables the advertisement of
the Adj-SIDs using the same Adjacency SID sub-TLV at the granularity
level of each L2 Bundle member link so that traffic may be steered
over that specific member link.
Note that the new advertisements at the L2 Bundle member link level
in this document are intended to be provided to external (to OSPF)
entities and does not alter or change OSPF route computation process.
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