The AS_PATHLIMIT Path Attribute

Document Type Expired Internet-Draft (idr WG)
Last updated 2007-01-05
Stream IETF
Intended RFC status (None)
Expired & archived
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This document describes the 'AS path limit' (AS_PATHLIMIT) path attribute for BGP. This is an optional, transitive path attribute that is designed to help limit the distribution of routing information in the Internet. By default, prefixes advertised into the BGP graph are distributed freely, and if not blocked by policy will propagate globally. This is harmful to the scalability of the routing subsystem since information that only has a local effect on routing will cause state creation throughout the default-free zone. This attribute can be attached to a particular path to limit its scope to a subset of the Internet.


Tony Li (

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