Constrain Attribute announcement within BGP

The information below is for an old version of the document
Document Type Expired Internet-Draft (idr WG)
Authors Keyur Patel  , Jim Uttaro  , Bruno Decraene  , Wim Henderickx  , Jeffrey Haas 
Last updated 2017-11-20 (latest revision 2017-05-19)
Stream Internet Engineering Task Force (IETF)
Expired & archived
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


[RFC4271] defines four different categories of BGP Path attributes. The different Path attribute categories can be identified by the attribute flag values. These flags help identify if an attribute is optional or well-known, Transitive or non-Transitive, Partial, or of an Extended length type. BGP attribute announcement depends on whether an attribute is a well-known or optional, and whether an attribute is a transitive or non-transitive. BGP implementations MUST recognize all well-known attributes. The well-known attributes are always Transitive. It is not required for BGP implementations to recognise all the Optional attributes. The Optional attributes could be Transitive or Non-Transitive. BGP implementations MUST store and forward any Unknown Optional Transitive attributes and ignore and drop any Unknown Optional Non-Transitive attributes. Currently, there is no way to confine the scope of Path attributes within a given Autonomous System (AS) or a given BGP member-AS in Confederation. This draft defines attribute extensions that help confine the scope of Optional attributes within a given AS or a given BGP member-AS in Confederation


Keyur Patel (
Jim Uttaro (
Bruno Decraene (
Wim Henderickx (
Jeffrey Haas (

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