Route Reflector

Unanswered Question
Feb 25th, 2007

i want to make sure some defination of route reflector as i got confuse:

Originator ID: this is set by route reflector and its router ID of the peer from which it received the route.

Cluster List: its is creatd on route reflector during the route reflection and it is stripped out whent it is advertise to external peeer.

i just want to know that my this understanding is correct or not.



I have this problem too.
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Jon Marshall Sun, 02/25/2007 - 10:58

Hi Devang

The Originator ID is the router ID of the roter that orginated a route within the local AS. A route refelctor should not advertise a route back to the router that orginated the route.

The Cluster List is created by a Router reflector. When a route reflector reflects a route to a non-client of the router reflector it appends it's cluster ID to the Cluster list. If the Cluster list doesn't exist it creates one.

In normal circumstances a BGP speaking router cannot forward a route learned from one internal peer to another internal peer. Because route reflectors relax this rule they must have some way to avoid routing loops. That's what the originator id and cluster id are used for.



devang_etcom Sun, 02/25/2007 - 12:50

ya thats what it is:

originator id and the cluster id both are used to prevent the loop in the same AS when they have one or more then one route reflector clustor...

and EBGP peer will not advertise this originator ID and the cluster list to the external EBGP peer in the other AS...right!!!



Jon Marshall Sun, 02/25/2007 - 23:29


Yes they will be stripped as they would be meaningless in another AS.



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