Generic Route Constraint Distribution Mechanism for BGP
draft-zzhang-idr-bgp-rt-constrains-extension-01
idr Z. Zhang
Internet-Draft J. Haas
Updates: 4684 (if approved) Juniper Networks
Intended status: Standards Track January 11, 2021
Expires: July 15, 2021
Generic Route Constraint Distribution Mechanism for BGP
draft-zzhang-idr-bgp-rt-constrains-extension-01
Abstract
This document defines a mechanism based upon Constrained Route
Distribution for BGP (RFC 4684) that works with various types of BGP
Community-like Path Attributes. Similar to RFC 4684, this mechanism
can be used to build a route distribution graph to limit the
propagation of BGP Routes. Unlike RFC 4684, this mechanism is not
restricted to BGP Extended Communities (RFC 4360).
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 15, 2021.
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Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Constrained Route Distribution . . . . . . . . . . . . . 3
1.2. Brief Summary of Constrained Route Distribution Procedure 3
1.3. Need for a Generic Route Constraint Distribution
Mechanism . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Community-like Attributes . . . . . . . . . . . . . . . . . . 5
2.1. Definition of Community-like Attributes . . . . . . . . . 5
2.2. Prefix Structure of BGP Community-like Attributes . . . . 5
3. Specification . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1. NLRI Definition . . . . . . . . . . . . . . . . . . . . . 7
3.2. NLRI Length Encoding . . . . . . . . . . . . . . . . . . 7
3.3. Operation . . . . . . . . . . . . . . . . . . . . . . . . 8
4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.1. IPv6 Specific Extended Communities . . . . . . . . . . . 8
4.2. Large BGP Communities . . . . . . . . . . . . . . . . . . 9
4.3. Bitmask Route Target . . . . . . . . . . . . . . . . . . 10
4.3.1. AS Number Bitmask Route Target . . . . . . . . . . . 11
4.3.2. IPv6 Address Bitmask Route Target . . . . . . . . . . 11
5. Security Considerations . . . . . . . . . . . . . . . . . . . 11
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
8.1. Normative References . . . . . . . . . . . . . . . . . . 12
8.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
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1.1. Constrained Route Distribution
In BGP/MPLS Layer 3 VPNs [RFC4364], Route Target Extended Communities
[RFC4360] are used to control VPN membership. Networks providing VPN
services may be large. In such networks, VPN routes for a given VPN
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