3Com 10014299 manual Networking diagram of configuring AS confederation

472CHAPTER 30: CONFIGURING BGP

Figure 154 Networking diagram of configuring AS confederation

		AS100
Router A		Router B
AS1001		AS1002
172.68.10.1		172.68.10.2
	Ethernet
172.68.10.3
		172.68.1.1
156.10.1.1	Router C	172.68.1.2	Router D
		AS1003

156.10.1.2

Router E

AS200

1Configure Router A:

[RouterA] bgp 1001 [RouterA-bgp] undo synchronization

[RouterA-bgp]confederation id 100

[RouterA-bgp]confederation peer-as 1002 1003

[RouterA-bgp]peer 172.68.10.2 as-number 1002

[RouterA-bgp]peer 172.68.10.3 as-number 1003

2Configure Router B:

[RouterB] bgp 1002 [RouterA-bgp] undo synchronization

[RouterB-bgp]confederation id 100

[RouterB-bgp]confederation peer-as 1001 1003

[RouterB-bgp]peer 172.68.10.1 as-number 1001

[RouterB-bgp]peer 172.68.10.3 as-number 1003

3Configure Router C:

[RouterC] bgp 1003 [RouterA-bgp] undo synchronization

[RouterC-bgp]confederation id 100

[RouterC-bgp]confederation peer-as 1001 1002

[RouterC-bgp]peer 172.68.10.1 as-number 1001

[RouterC-bgp]peer 172.68.10.2 as-number 1002

[RouterC-bgp]peer 156.10.1.2 as-number 200

[RouterC-bgp]peer 172.68.1.2 as-number 1003

Configuring BGP Route Router B receives a BGP update message and forwards the update to Router C, Reflector which is configured as a route reflector and has two clients: Router B and Router

D. When Router C receives routing update from Router B, it reflects the information to Router D. Therefore, an IBGP connection is not necessary between Router B and Router D, because Router C will reflect the information to Router D.