Shortest Path Routing Extensions for BGP Protocol
draft-ietf-lsvr-bgp-spf-11
Network Working Group K. Patel
Internet-Draft Arrcus, Inc.
Intended status: Standards Track A. Lindem
Expires: February 4, 2021 Cisco Systems
S. Zandi
LinkedIn
W. Henderickx
Nokia
August 3, 2020
Shortest Path Routing Extensions for BGP Protocol
draft-ietf-lsvr-bgp-spf-11
Abstract
Many Massively Scaled Data Centers (MSDCs) have converged on
simplified layer 3 routing. Furthermore, requirements for
operational simplicity have led 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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This Internet-Draft will expire on February 4, 2021.
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document authors. All rights reserved.
Patel, et al. Expires February 4, 2021 [Page 1]
Internet-Draft BGP Protocol SPF Extensions August 2020
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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 . . 5
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 . . . . . . . . . . . . . . . . . . . . 6
4.1. Node NLRI Usage . . . . . . . . . . . . . . . . . . . . . 7
4.1.1. Node NLRI Attribute SPF Capability TLV . . . . . . . 7
4.1.2. BGP-LS Node NLRI Attribute SPF Status TLV . . . . . . 8
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 SPF Status TLV . . . . . . 9
4.3. Prefix NLRI Usage . . . . . . . . . . . . . . . . . . . . 10
4.3.1. BGP-LS Prefix NLRI Attribute SPF Status TLV . . . . . 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
5.4. NEXT_HOP Manipulation . . . . . . . . . . . . . . . . . . 16
5.5. IPv4/IPv6 Unicast Address Family Interaction . . . . . . 16
5.6. NLRI Advertisement and Convergence . . . . . . . . . . . 17
5.6.1. Link/Prefix Failure Convergence . . . . . . . . . . . 17
5.6.2. Node Failure Convergence . . . . . . . . . . . . . . 17
5.7. Error Handling . . . . . . . . . . . . . . . . . . . . . 18
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
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