Hi,
This is a draft that I presented at IDR earlier.
The idea is to add a new metric to BGP that allows for better traffic
engineering for incoming traffic, reducing the need to deaggregate.
In the new version, the new IAC attribute is compared very late in the
path selection algorithm: after the IGP cost, before the router ID
comparison. This way, it doesn't influence what happens in large ASes
where the IGP cost is a relevant metric and it also doesn't overrule
the MED. But if all these are the same, which will be especially
common in smaller ASes, this will first of all randomize the selection
of the path based on the AS numbers involved, and secondly, allow both
the source of the announcement and the local AS to apply push away or
pull in additional traffic.
Feedback from the grow community would be much appreciated.
Begin forwarded message:
Title : A BGP Inter-AS Cost Attribute
Author(s) : I. van Beijnum, R. Winter
Filename : draft-van-beijnum-idr-iac-02.txt
Pages : 7
Date : 2009-03-09
Although BGP implementations have extensive path selection
algorithms, in practice operators have trouble performing
satisfactory traffic engineering of incoming traffic based on BGP
attributes that are taken into account in the path selection
algorithm alone. For this reason, many ASes deaggregate their
address range(s) into smaller blocks and announce these blocks
differently to different neighboring ASes in order to arrive at the
desired traffic flow. This practice contributes to the growth of the
global routing table, which drives up capital expenditures for
networks engaging in inter-domain routing. This memo introduces a
new inter-domain metric that supports finer-grained traffic
engineering than current BGP attributes.
A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-van-beijnum-idr-iac-02.txt
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