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Re: Deaggregation Disease

  • From: Joe Abley
  • Date: Fri Jul 21 11:39:42 2006


On 21-Jul-2006, at 11:20, Saku Ytti wrote:

On (2006-07-21 10:48 -0400), Joe Abley wrote:

As it happens, Tony Li, Rex Fernando and I wrote up a proposal for a
new attribute which might help in some of these situations. (It's a
crude mechanism, but not as crude as NO_EXPORT).

   http://www.ietf.org/internet-drafts/draft-ietf-idr-as-
pathlimit-02.txt


 I'm sure I'm not first one to to think about 'TTL' to AS hops
(http://www.merit.edu/mailinglist/mailarchives/old_archive/2002-10/msg00394.html),
of course different reason at that time :). Other thing I was thinking
about was ability to have include/exclude AS#'s community/attribute.

That seems to me like another perfectly valid approach, and one that already exists to some extent (e.g. by pre-poisoning AS_PATH attributes with AS numbers of remote networks that you don't want to accept particular routes). I'm told that IDRP has inclusion and exclusion lists which provide more exhaustive implementation of this kind of idea, too.

However, for some applications those mechanisms rely on knowing the topology one or more AS hops away from your network; AS_PATHLIMIT doesn't. To my eye the two approaches seem complementary.

[To be clear, incidentally, Tomy, Rex and I made no claim to be the original authors of the idea we were documenting in this draft:

8. Acknowledgements

The editors would like to acknowledge that they are not the original
initiators of this concept. Over the years, many similar proposals
have come our way, and we had hoped that self-discipline would cause
this type of mechanism to be unnecessary. We were overly optimistic.

   The names of those who originally proposed this are now lost to the
   mists of time.  This should rightfully be their document.  We would
   like to thank them for the opportunity to steward their concept to
   fruition.]


Joe