Nokia IPSO 4.0 manual Confederations, Nokia Network Voyager for Ipso 4.0 Reference Guide 409

No special configuration is required on the route reflection clients. From a client perspective, a route reflector is a normal IBGP peer. Any BGP version 4 speaker should be able to be a reflector client.

for further details, refer to the route reflection specification document (RFC 2796 as of this writing).

Non-client

Non-client

AS1

Nokia

IBGP

Nokia

Platform A

Platform D

AS676

IBGP

IBGP

Cluster

Nokia

Nokia

EBGP

Platform F

Platform B

route reflector

IBGP

Nokia

Nokia

Platform C

Platform E

Nokia

Client

Client

Platform G

00328

AS1 has five BGP-speaking routers. With Router B working as a route reflector, there is no need to have all the routers connected in a full mesh.

Confederations

An alternative to route reflection is BGP confederations. As with route reflectors, you can partition BGP speakers into clusters where each cluster is typically a topologically close set of routers. With confederations, this is accomplished by subdividing the autonomous system into multiple, smaller ASes that communicate among themselves. The internal topology is hidden from the outside world, which perceives the confederation to be one large AS.

Each distinct sub-AS within a confederation is referred to as a routing domain (RD). Routing domains are identified by using a routing domain identifier (RDI). The RDI has the same syntax as an AS number, but as it is not visible outside of the confederation, it does not need to be globally unique, although it does need to be unique within the confederation. Many confederations find it convenient to select their RDIs from the reserved AS space (ASes 64512 through 65535 (see RFC 1930)). RDIs are used as the ASes in BGP sessions between peers within the confederation.

The confederation as a whole, is referred to by a confederation identifier. This identifier is used as the AS in external BGP sessions. As far as the outside world is concerned, the confederation ID is the AS number of the single, large AS. For this reason, the confederation ID must be a globally unique, normally assigned AS number.

Note

Do not nest confederations.

Nokia Network Voyager for IPSO 4.0 Reference Guide 409