Title:
Interdomain Ingress Traffic Engineering through Optimized AS-Path Prepending
Interdomain Ingress Traffic Engineering through Optimized AS-Path Prepending
Author(s)
Dovrolis, Constantine
Zegura, Ellen W.
Gao, Ruomei
Zegura, Ellen W.
Gao, Ruomei
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Abstract
In Interdomain Ingress Traffic Engineering
(INITE), a "target" Autonomous System (AS) aims to control
the ingress link through which the traffic of one or more
upstream source networks flows to the target network or to
its customers. Currently, there are few methodologies for
systematic INITE. In practice, ISPs often attempt to manipulate,
mostly in a trial-and-error manner, the AS-Path
length attribute of upstream routes through a simple technique
known as prepending (or padding). In this paper,
we focus on prepending and propose a polynomial-time algorithm
(referred to as OPV) that determines the optimal
padding for an upstream route at each ingress link of the
target network. Specifically given a set of "elephant" source
networks for a particular customer of the target network,
and a set of maximum load constraints on the ingress links
of the latter, OPV determines the minimum padding at each
ingress link so that the load constraints are met, when it is
feasible to do so. OPV requires as input an AS-Path length
estimate from each source to each ingress link. We describe
how to estimate this matrix, leveraging the BGP Looking
Glass Servers that are abundant today for monitoring interdomain
routing. To deal with unavoidable inaccuracies
in the AS-Path length estimates, and also to compensate
for the generally unknown BGP tie-breaking process in upstream
networks, we develop a robust variation (RPV) of
the OPV algorithm. We show that RPV manages to identify
a padding vector that meets the given maximum load constraints,
when it is feasible to do so, even in the presence of
inaccurate AS-Path lengths and unknown BGP tie-breaking
behavior.
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Date Issued
2005
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448627 bytes
Resource Type
Text
Resource Subtype
Technical Report