Shortest Path Routing Extensions for BGP Protocol
draft-ietf-lsvr-bgp-spf-05
Network Working Group K. Patel
Internet-Draft Arrcus, Inc.
Intended status: Standards Track A. Lindem
Expires: January 23, 2020 Cisco Systems
S. Zandi
Linkedin
W. Henderickx
Nokia
July 22, 2019
Shortest Path Routing Extensions for BGP Protocol
draft-ietf-lsvr-bgp-spf-05
Abstract
Many Massively Scaled Data Centers (MSDCs) have converged on
simplified layer 3 routing. Furthermore, requirements for
operational simplicity have lead many of these MSDCs to converge on
BGP as their single routing protocol for both their fabric routing
and their Data Center Interconnect (DCI) routing. This document
describes a solution which leverages BGP Link-State distribution and
the Shortest Path First (SPF) algorithm similar to Internal Gateway
Protocols (IGPs) such as OSPF.
Status of This Memo
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document authors. All rights reserved.
Patel, et al. Expires January 23, 2020 [Page 1]
Internet-Draft BGP Protocol SPF Extensions July 2019
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. BGP Shortest Path First (SPF) Motivation . . . . . . . . 4
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 5
2. BGP Peering Models . . . . . . . . . . . . . . . . . . . . . 5
2.1. BGP Single-Hop Peering on Network Node Connections . . . 5
2.2. BGP Peering Between Directly Connected Network Nodes . . 6
2.3. BGP Peering in Route-Reflector or Controller Topology . . 6
3. BGP-LS Shortest Path Routing (SPF) SAFI . . . . . . . . . . . 6
4. Extensions to BGP-LS . . . . . . . . . . . . . . . . . . . . 7
4.1. Node NLRI Usage and Modifications . . . . . . . . . . . . 7
4.2. Link NLRI Usage . . . . . . . . . . . . . . . . . . . . . 8
4.2.1. BGP-LS Link NLRI Attribute Prefix-Length TLVs . . . . 9
4.2.2. BGP-LS Link NLRI Attribute BGP SPF Status TLV . . . . 9
4.2.3. BGP-LS Prefix NLRI Attribute SPF Status TLV . . . . . 10
4.3. Prefix NLRI Usage . . . . . . . . . . . . . . . . . . . . 10
4.4. BGP-LS Attribute Sequence-Number TLV . . . . . . . . . . 10
5. Decision Process with SPF Algorithm . . . . . . . . . . . . . 11
5.1. Phase-1 BGP NLRI Selection . . . . . . . . . . . . . . . 12
5.2. Dual Stack Support . . . . . . . . . . . . . . . . . . . 13
5.3. SPF Calculation based on BGP-LS NLRI . . . . . . . . . . 13
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