BGP Configuration

[prashantb]

Hi Guys,

I have network with BGP.On both routers two different ISPs are terminated.I want incomming traffic of block 75.64.0.0 to 75.95.255.255 has to come through KMC router,if that router fails then it should come thru another Router name C_7200.

Pls guide me to configure BGP.

pls find the attached config.

Thanks

Prashant

[Giuseppe Larosa]

Hello Prashant,

let me make two notes:

a)

BGP has a rich set of tools but it is still a destination based routing protocol if this IP address block describes source ip addresses in the internet BGP cannot deal with this.

b)

for destinations specific routes are needed

even if the specified block would describe a destination it looks like your providers are sending you only a default route and this again doesn't allow to make one path preferred.

You should at least receive and accept prefixes describing the block as specific routes on primary router KMC to achieve the desired result if you mean destination addresses.

Hope to help

Giuseppe

[Harold Ritter]

Prashant,

If I understand you correctly, you want incoming traffic destined to 75.64.0.0/11 to come through KMC under normal conditions and through C_7200 as a backup.

You could use conditional advertisement to achieve this. Please refer to the following URL for more information on BGP conditional advertisement:

http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a0080094309.shtml

Regards

[prashantb]

No,

Currently 75.64.0.0/11 traffic is comming through C_7200 in my network.I want that traffic has to come thru KMC router.

[kerek]

Hi,

Let's prepend the AS path outgoing to the ISP through which you don't want the traffic to get. It will make the AS path longer in that direction therefore shorter through the desired ISP.

Hope it helps rate if does

Krisztian