Internet Engineering Task Force (IETF) J. Snijders Request for Comments: 8093 NTT Category: Standards Track February 2017 ISSN: 2070-1721
Deprecation of BGP Path Attribute Values 30, 31, 129, 241, 242, and 243
This document requests IANA to mark BGP path attribute values 30, 31, 129, 241, 242, and 243 as "Deprecated".
Status of This Memo
This is an Internet Standards Track document.
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Snijders Standards Track [Page 1]
RFC 8093 Deprecation of Squatted BGP Path Attributes February 2017
It has been discovered that certain BGP Path Attribute values have been used in BGP implementations that have been deployed in the wild while not being assigned by IANA for such usage. Unregistered usage of BGP Path Attribute values can lead to deployment problems for new technologies.
The use of these unregistered values was noticed when the BGP Large Communities attribute [RFC8092] was initially assigned value 30 by IANA. It was subsequently discovered that a widely deployed BGP-4 [RFC4271] implementation had released code that used path attribute 30 and that applied a "Treat-as-withdraw" [RFC7606] strategy to routes containing a valid Large Community attribute, since it was expecting a different data structure. Because these routes were dropped, early adopters of Large Communities were unreachable from parts of the Internet. As a workaround, a new Early IANA Allocation was requested.
The squatting of values 30, 31, 129, 241, 242, and 243 has been confirmed by the involved vendors or through source code review.
IANA has marked values 30, 31, 129, 241, 242, and 243 as "Deprecated" in the "BGP Path Attributes" subregistry under the "Border Gateway Protocol (BGP) Parameters" registry. The marking "Deprecated" means "use is not recommended" ([IANA-GUIDELINES]).