Route Target Constrain Extension
draft-zzhang-idr-bgp-rt-constrains-extension-00
idr Z. Zhang
Internet-Draft J. Haas
Updates: 4684 (if approved) Juniper Networks
Intended status: Standards Track July 12, 2020
Expires: January 13, 2021
Route Target Constrain Extension
draft-zzhang-idr-bgp-rt-constrains-extension-00
Abstract
This document specifies the extensions to Route Target Constrain
mechanism so that it works with various types of Route Targets of
arbitrary lengths.
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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This Internet-Draft will expire on January 13, 2021.
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
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Internet-Draft rtc-extension July 2020
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Specification . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Security Considerations . . . . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
6.1. Normative References . . . . . . . . . . . . . . . . . . 4
6.2. Informative References . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
The importation and propagation of BGP routes can be controled using
Route Targets [RFC4364] and Route Target Constrains [RFC4684].
A Route Target (RT) could be an 8-octet BGP Extended Community (EC)
or a 20-octet IPv6 Address Sepcfic EC, though the RT Constrain
mechanism specified in [RFC4684] was designed for the 8-octet RTs
only.
[I-D.ietf-idr-bgp-ipv6-rt-constrain] extends the mechanism to handle
IPv6 Address Specific RTs by allowing the NLRI prefix to be of 0 to
24 octets (vs. 0 to 12 octets as in [RFC4684]):
+-------------------------------+
| origin as (4 octets) |
+-------------------------------+
| route target (8 or 20 octets)|
~ ~
| |
+-------------------------------+
There is a limitation with the approach in [I-D.ietf-idr-bgp-ipv6-rt-
constrain] - when the prefix is not more than 12 octets, there is no
way to determine if the route target part is a partial IPv6 Address
Sepcific RT or a full/partial AS or IPv4 Address Specific RT.
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Additional types of RTs of arbitrary lengths could also be defined,
e.g. [I-D.zzhang-idr-bitmask-route-target]. To extend the RT
Constrain mechanisms in a generic way so that any forseeable types of
RTs can be used, this document proposes the extensions specified in
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