Routing Registries and Route Servers

Daniel Karrenberg Daniel.Karrenberg at
Thu Sep 15 10:24:21 UTC 1994

  > asp at (Andrew Partan) writes:
  > Please be careful about mixing route registries and route servers.  I
  > think each serves different purposes & different arguments can be made
  > for the usefulness of each.
  > I personally am not yet sure of the usefulness of route servers.
  > However I do think that route registries are very useful.

Indeed there appears to be (too) much confusion about those two.  
Definitely the Routing Registry is the more important and much more
general concept. Without the RR it would be difficult to
impossible to configure an operational Route Server.

Maybe a few informal (my personal view) definitions help:

Routing Registry

Definition: A neutral repository where ISPs can register their external
routing policies for retrieval by everyone needing this information. 

Problem addressed: The cross product of all external routing policies
represents the global Internet routing policy.  Without knowing a big
part of this, configuration and operation of an Internet with arbitrary
topology is currently impossible. 

Implementation: A database with a suitable schema and an Internet
retrieval method.  The minimal schema must represent autonomous systems,
the routes being originated by those ASes and the routing information
exchanged between ASes. 

Uses: Very many and general: Helps ISPs to configure their external
routing and to diagnose unexpected routing behavior.  Actually it is the
*only* way to tell what the *expected* routing behavior is in very many

Route Server

Definition: An external routing peer located at an Internet exchange
point that combines dynamic routing announcements with routing policy
and provides the result to its users.  It does not forward any packets. 
There can be multiple route servers using different policies.  Single
route servers using multiple policies have been proposed.  Use of route
servers is optional.  They can be used in addition to direct peerings. 

Problem addressed: n**2 peering problem at exchange points.  ISPs can
peer with just the route server and do not have to peer with any of the
ISPs that the route server combines information for.  This solves router
capacity problems as the route server keeps many more paths, peers and
isolates non significant routing changes from its users.  It also reduces
routing configuration maintenance. 

Implementation: A workstation with routing software.  Most commonly
(euphemism!) a Unix box with gated.  Configuration is derived (partly)
from Routing Registry. 

Uses: specialised, see above.

Routing Arbiter

Definition: Awardee of a NSF cooperative agreement operating a Routing 
Registry and Route servers at the NAPs.

Problem Addressed: see above

Implementation: see above

Uses: server those connected at the NAPs

More information about the NANOG mailing list