Heads up: Long AS-sets announced in the next few days

David Schwartz davids at webmaster.com
Thu Mar 3 22:28:43 UTC 2005

> On 2 Mar 2005, at 22:30, David Schwartz wrote:
> > 	Please just clarify the following point: do you intend to advertise
> > paths
> > containing AS numbers belonging to other entities on the public
> > Internet
> > without the permission of the owners of those AS numbers? You admit
> > that you
> > don't know what the consequences of this injection will be.

> Prepending announcements with remote AS numbers has been a well-known
> technique for preventing prefixes from propagating to particular ASes
> for a long time.

	And therefore such use would not be considered experimental. We are talking
about experimenting with routes that falsely claim to have passed through
another autonymous system.

> The AS_PATH attribute is a loop detection mechanism, and a determinant
> in path selection. What other magic is there in it that requires such
> careful consideration? Why should anybody need to get permission from
> remote operators before deciding what attributes to include in their
> own advertisements?

	Every piece of BGP documentation I have ever seen says that this attribute
documents the ASes that the route has actually passed through.

> Do I need to get permission from Sprint before I include 1239:100 as a
> community-string attribute on my own advertisement, too?

	You certainly need their permission before you can advertise routes that
falsely came to have passed through their network! And yes, I would argue
that you do need permission to attach someone else's community string to
your routes and that it would be considered at least terribly bad manners to
use undocumented community strings from other people's ASes. (Documentation,
of course, equates to permission.)

> > 	It seems to me that there are enough issues with this type of
> > experimentation *with* the permission of the AS numbers you plan to
> > use. But
> > the ethical issues with using them without such permission seems to me
> > to be
> > insurmountable.

> The ethical issues seem to be non-existent, to my way of thinking, and
> hence trivial to surmount :-)

	I'm curious where you would draw the line then. And I'm curious what you
think is the point of registering AS numbers at all, if it's okay to use
other people's without their permission.


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