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Re: Order of ASes in the BGP Path


From: Tom Sanders <toms.sanders () gmail com>
Date: Tue, 30 Aug 2005 06:30:23 +0530



You can *not* merge AS_SET's, as the current BGP specs imply an
AS_SET has a fixed path-length, hence you should NOT merge the sets
in:

       {1 2} [3 4] [5 6]

into:

       {1 2} [3 4 5 6]

as the former path has a length of 3, the latter a length of just 2 -
merging sets could change their meaning. Note though that you're not
at all likely to see such paths with BGP speakers implementing the
RFC / draft-ietf-idr-bgp-26.txt draft.

This is one thing that i have always been aware of but dont see it
mentioned in the BGP draft which can be quite confusing to the
newbies. Is it possible to explicitly mention this in
draft-ietf-idr-bgp-26.txt?

Toms.


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