consistent policy != consistent announcements

Randy Bush randy at
Thu Mar 13 14:19:00 UTC 1997

>> A normal condition of peering between consenting adults is that the peers
>> have consistent policy across all points where they peer.
> [example of a quasi-consistent scenario skipped]
> 1) it's ok with consent of parties involved (i.e. you may want to coordinate
> fancy policies with peers)

In this particular case, a peer is complaining about a simple policy.  Is
there an other policy that would make them happy.  Can I hope that it is not
complex, hardier to maintain, or have undesirable side effects?  Is the peer
justified in asking me to implement different policy and what other

> 2) generally speaking, BGP path length is too blunt an instrument.  More
> fine-grained control is needed to allow peers to fine-tune balance of
> their interests.  I'm sorry to be too naive, but i'm repeating that for
> years and nobody seems to agree that BGP needs real metrics.  How come?

I thought that there was some plan to experiment with this, but have seen
nothing recently.  Perhaps the BGP artists have become otherwise occupied.
[ what will changing the length of the ASN do to the community format? ]

> 3) on a philosophical level, all involved parties should have a way to
> control destiny of routes, to a some extent.  Right now, it's either
> control local to the destination (local preferences), or control by
> adjacent neighbour (MEDs).  There's no way to extend it further (save for
> as-replication kludgery) or to combine local and remote metrics in any
> meaningful way.

I agree that this is worth exploring.  But it is a philosophical problem and
protocol design issue, thus perhaps better suited to other fora.  I am just
an unsmooth operator trying to understand how to be a good citizen and how
far I may have to bend to be one.

The reason I posted to NANOG is that I have a real today problem with an
actual unhappy peer.  And I am trying to understand if there is something
reasonable I can do to make them happy.  The inconsistencies described may
also cause problems for real world routing analysis tools.

So all good points.  And I agree with you philosophically.  But please bail
me out today.


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