iBGP OSPF interaction
Posted on 2007-12-03
Hi there! I've got a question regarding iBGP and OSPF. A bit confused really...Hope someone can clear it up.
Here's what we got:
ISP1 ISP2 ISP1 ISP2
| | | |
| | | |
Router1 ------------- Router2
Now router1 amd 2 are running iBGP and OSPF. I've got the following links between us and ips1 and 2:
Router1 --- isp1 - 195.xx.xx.xx/29
Router1 --- isp2 - 87.xx.xx.164/30
Similar for router 2:
Router2 --- isp1 - 195.xx.xx.xx/29
Router2 --- isp2 - 87.xx.xx.200/30
OSPF is running between the 2 routers (For iBGP TCP connection), only one interface is included in ospf (only the one that connects the 2 routers) which makes sense. I didn't set this up, but just trying to understand why under ospf, the subnets connected to isp1 and 2 are included in the network statement on both routers?
I am not sure what the purpose is but wouldn't we be ok just by including our network subnet in the network statement and not the whole lot especially since we are using 'no synchronisation' under BGP? We are advertising only 2 subnets (see below) in BGP.
router ospf 10
net 195.xx.xx.xx/29 (does this need to be here??)
net 87.xx.xx.164/30 (does this need to be here??)
net 91.x.x.x/23 (our network)
net net 195.x.x.x/24 (our network)
Similar setup on both routers for OSPF. Just trying to understand the interaction of iBGP and OSPF. I hope I have explained this well enough?