North American Network Operators Group

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Re: Routescience?

  • From: Peter Francis
  • Date: Thu Aug 23 13:55:38 2001

>  no, the PathControl device does *not* adjust outgoing
>advertisements in any way; all prefixes that we repeat
>carry the NO_EXPORT attribute.

And if the ISP using your box has downstream BGP customers in different ASes?

The NO_EXPORT tag really serves no purpose here because any ISP that would be avertising your bozxes routes to its upstreams already has a much bigger problem.

The NO_EXPORT tag just makes it more complicated to get the "better paths" to the ISPs BGP customers.

Adding unnecessary locks just to make something sound "safe" is usually a surefire way cause a disaster when a slightly-clued person clears the tag to get the routes to downstreams and suddenly discovers they are announcing your boxes routes to the world.

Do you guys have a white paper on all this?


>cheers -- Sean
>"Christopher A. Woodfield" wrote:
>> Can/will the box adjust inbound route selection via the use of prepending
>> and/or provider communities?
>> -C
>> > Once more, we do not cause the stub AS's own advertisement of themselves
>> > to change.  We specifically avoid touching locally originated prefixes.
>> > If the ISP is currently accepting any of the routes PathControl is
>> > designed to change, then the AS is not stub, it's transit.  Hopefully
>> > this clarifies an important issue.
>> >
>> > (Referring back to Paul Vixie's point, we have found that careful
>> > optimization of a single outbound step has very substantial payoffs in
>> > terms of the end to end, bidirectional performance.  The figures quoted
>> > on our web page and in the press release refer to this: end to end
>> > application speedup caused solely by outbound route selection!)
>> >
>> > Mike
>> --
>> ---------------------------
>> Christopher A. Woodfield                [email protected]
>> PGP Public Key: