Preventing the Unnecessary Propagation of BGP Withdraws

vvandens — Tue, 10 Mar 2009 14:23:49 +0000

Due to the way BGP paths are distributed over iBGP sessions inside an
Autonomous System (AS), a BGP withdraw that follows a failure may be propa-
gated outside the AS although other routers of the AS know a valid alternate path.
This causes transient losses of connectivity and contributes to the propagation of
a large number of unnecessary BGP messages. In this paper, we show, based on
RouteViews data, that a signiﬁcant number of BGP withdraws are propagated
even though alternate paths exists in another border router of the same AS.

INL: IP Networking Lab - Churn

Preventing the Unnecessary Propagation of BGP Withdraws