ANS-CIX Interconnection

Jordan Becker becker at
Fri Oct 2 00:04:21 UTC 1992

> From: bjp at
> Subject: Re: ANS to CIX Interconnection
> Cc: regional-techs at
> Date: Wed, 30 Sep 1992 20:52:58 GMT
> To: mak at
> Can you tell me why you aren't keeping complete information in the
> CNSSs instead of the ENSSs?

Both ENSSs and CNSSs normally have complete routing information.  The
ENSSs will selectively announce commercial destination networks only
to the participating service providers.

It is possible for an ENSS to have partial routing information.
However, one problem with this is that multiple regionals peer with
the same ENSS at several locations.  If an ENSS had partial
information to administer some restriction policy, this would affect
all regionals that peer with that ENSS.  That might adversely affect
those regionals that wish to receive the additional routes, and would
certainly result in more work to maintain the policy routing database,
and routing software, not to mention the management of consensus
between each regional that shares an ENSS.

There are ways for a regional to block this traffic, even if they
continue to use default routes (e.g. create a static route for the
commercial destinations to "black hole" the traffic).  However it does
require some effort by the regional as several people have correctly
pointed out.

> I can't see the problem you are solving by
> engaging in this activity.

The basic problem is to give remote CIX members (e.g. some regionals)
access to the CIX using the ANSNET as transit.


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