text about experimental attributes

Daniel,
Here is the proposed text about experimental attributes.  We
would hope that this would be embedded in RIPE 81 ++
         --Elise

--------------------proposed text---------------------
We envision that over time the requirements for describing routing policy 
will evolve. The routing protocols will evolve to support the requirements 
and the routing policy description syntax will need to evolve as well.  
For that purpose, a separate document will describe experimental syntax 
definitions for policy description.  This document will be updated when 
new objects or attributes are proposed or modified.

Two new attributes of the AS object which are proposed and supported
by the Merit Routing Registry are as-transit and db-selector.

as-transit describes the transit preferences of an AS.  It allows an AS
to describe its path preference in order to reach certain destinations.
The AS(s) specified in the path preference may or may not be an
immediate neighbor of the AS defined in the AS object. as-transit accommodates
policy decisions involving AS path whereas as-in and as-out do not.
It is not unusual for ASs to have routing policies which involve path 
selection based on AS. Emerging protocols like SDRP will allow an AS to 
choose a path independent of a neighboring ASs path choice. as-transit 
permits descriptions based on AS path selection.

The DataBase Selector (db-selector) function allows one to take advantage 
of information registed in other Registries.  It permits the selection of 
networks in a database based on their attributes.  It is proposed to be 
used within the as-in/as-out attribute family to make the description 
of policy concise.  For example, if an AS has the policy of not accepting 
any routes from country XYZ, the AS can use the db-selector to check a 
database which has a network and country attribute and relate that 
information to the information in the routing registry. The advantage 
of referencing another database is that the routing registry will 
avoid duplicating the information maintained in other imformation registries.
   
Detailed examples and syntax are described in document xxxx. 




-------- Logged at  Thu Jun 30 23:01:05 MET DST 1994  ---------