Extreme Networks ExtremeWare XOS Guide Manual page 208

Exterior Gateway Routing Protocols
Route Confederation Example
Figure 39 shows an example of a confederation.
Figure 39: Routing confederation
AS 200
A
EBGP
192.1.1.17/30
EBGP
E
In this example, AS 200 has five BGP speakers. Without a confederation, BGP would require that the
routes in AS 200 be fully meshed. Using the confederation, AS 200 is split into two sub-ASs: AS65001
and AS65002. Each sub-AS is fully meshed, and IBGP is running among its members. EBGP is used
between sub-AS 65001 and sub-AS 65002. Router B and router D are EBGP peers. EBGP is also used
between the confederation and outside ASs.
To configure router A, use the following commands:
create vlan ab
configure vlan ab add port 1
configure vlan ab ipaddress 192.1.1.6/30
enable ipforwarding vlan ab
configure ospf add vlan ab area 0.0.0.0
create vlan ac
configure vlan ac add port 2
configure vlan ac ipaddress 192.1.1.17/30
enable ipforwarding vlan ac
configure ospf add vlan ac area 0.0.0.0
disable bgp
configure bgp as-number 65001
configure bgp routerid 192.1.1.17
configure bgp confederation-id 200
enable bgp
create bgp neighbor 192.1.1.5 remote-AS-number 65001
208
SubAS 65001
192.1.1.6/30
IBGP
192.1.1.18/30
C
192.1.1.13/30
IBGP
SubAS 65002
B
192.1.1.5/30
192.1.1.22/30
192.1.1.21/30
192.1.1.14/30
D
192.1.1.9/30
EBGP
192.1.1.10/30
EX_043
ExtremeWare XOS 10.1 Concepts Guide