3Com 3036, Configuration Manual

Page: 464 / 762

460 C
HAPTER
30: C
ONFIGURING
BGP
By default, an aggregate is disabled.
Configure BGP Route
Reflector
To guarantee the connectivity between the IBGP peers, an all-closed network
should exist between IBGP peers. In some networks, the internal BGP network can
become very large (with more than one hundred sessions in each router), resulting
in huge overhead. The route reflector designates a central router as the core of the
internal sessions. Multiple BGP routers can become peers with this central router,
and then multiple route reflectors can be peers with each other.
Since the route reflector is the center of other routers, other routers are called
client routers from the viewpoint of the reflector. The client routers are peers of
the route reflector and exchange routing information. The route reflector forwards
(reflects) information among the client routers in turn.
As shown in the following diagram, Router A receives an update from an external
peer and transfers it to Router B. Router B is a route reflector, which has two
clients: Router A and Router C.
Router B can reflect the routing update from client Router A to client Router C. In
this instance, the session between Router A and Router C is unnecessary because
the route reflector forwards the BGP information to Router C.
Figure 152 Schematic diagram of route reflector
The route reflector divides the IBGP peers into two types: client and non-client.
Using the peer reflect-client command, you can configure the internal neighbors
that can communicate with the route reflector. The neighbors are called the client
group members of the route reflector, and other neighbors that are not configured
as the non-clients are the non-client group members of the route reflector.
Add a piece of routing aggregate
information to the BGP routing table
aggregate address mask [ as-set ] [
detail-suppressed ] [
suppress-policy policy-name ] [
origin-policy policy-name ] [
attribute-policy policy-name ]
Delete a piece of routing aggregate
information to the BGP routing table
undo aggregate address mask
EBGP
EBGP
Route Reflector
Reflected router
Update route
Router B
Router A
Router C