AS690 advisory update

Steve Heimlich heimlich at
Mon Nov 13 16:29:08 UTC 1995


As previously mentioned, ANS is moving to a new configuration system
which will eliminate the need for registering AS690 advisories with
RIPE-181 route objects.  Our initial deployment described below
has gone well, and as a result we will freeze our aut-num (currently
still machine generated based on advisories) on Friday, 11/17, at
midnight ET (Saturday, 11/18, 5am GMT).  Tuesday morning's AS690
config run will use the frozen aut-num.

After this time, AS690 advisories will be ignored.  Policy toward
routes registered in the IRR will be based solely on origin AS.
The origin AS will be expanded to the set of route objects registered
for that origin AS; the resulting list of prefixes will be used in
generating router configurations, as today.

Refinement of AS690 import policies will begin on a per AS basis
next week, starting with large origin ASes.  The human readable
version of the 18,000 line AS690 aut-num is currently available


To: nanog at
Subject: AS690 policy configuration changes
Date: Mon, 06 Nov 1995 18:43:22 -0500
From: Steve Heimlich <heimlich at>


Starting with Friday [11/10] morning's config run, AS690 will pick
up any route listed in various routing registries, including both
those routes with advisories and those routes without advisories.

ANS customers will not be affected by this change.

Routes without advisories will be examined for origin AS and will
inherit the most popular policy currently used for that AS.  For
example, if a route for 147.225/16 (origin AS1660) were listed
without an advisory, we would configure ourselves to listen for
147.225/16 in the same way that we listen to most other AS1660
routes (only from AS 1324 in this case).

If a route is registered in an AS for which we don't have existing
policy, it will not be routed.  In the example above, if 147.225/16
were registered without an aggregate, and it were the only route
registered with origin 1660, then we will not route it.  We have
a tool which flags such new ASes, and policy toward them will be
created regularly.  The rate of growth in number of ASes is not
high, particularly relative to the rate of growth in number of

For now, we will continue to build our policy dynamically from the
advisory attributes.  Assuming that this hybrid deployment goes
well, we intend to freeze our policy and convert to a system which
ignores advisories altogether.  With this system, the mechanics of
shifting policy will be quite easy (essentially involving only
ANS).  I expect to announce that freeze and shift in the next week
or so.  At that point, those folks who want to strip AS690 advisories
from any database may do so without a problem; as mentioned above,
any advisories registered after that time will be ignored.


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