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New Member

Policy based touting

I have enable PBR on one of my interfaces of 7513.which decide on basis of source IP block and chosse next hop. My question is what will happen if next hop is unavialable (down).will it go to alternate hop as decided by BGP.( I am running BGP, OSPF in my network) and next hops are EBGP peers?

REgards

Raza Bhutta

6 REPLIES
Cisco Employee

Re: Policy based touting

If the next-hop IP address is not reachable, then BAD luck, it won't go to next policy. You can though set 2 next-hops, if one fails, it will then it will use the next one.

eg;

route-map yusuf permit 10

match ip address 1

set ip next-hop 1.1.1.1 2.2.2.2

HTH

R/Yusuf

New Member

Re: Policy based touting

Thanks for reply

Its mean when we apply PBR on interface ,normal routing will not work for that particular interface i.e OSPF and BGP will not be effective for this interface

Raza

New Member

Re: Policy based touting

The question is how would the router know the host is down without some sort

of heartbeat.

My next question, and this shows my shallow knowledge of PBR, but can the

next-hop be a non-local address? For instance, can router 1 which is

connected to subnets A and B use a host on subnet C as a next-hop, despite

the fact that router 1 has to go through router 2 to get to subnet C? If it

can, would this create a tunnel, so that traffic would get to the next-hop

address, or would Router 2 receive the packets and try to route them itself?

Silver

Re: Policy based touting

PBR using "verify-availability" can verify next hop reachability in route-maps.

You can also, as mentioned, specify a non connected next hop. This would result in a recursive lookup in the routing table. Also you can specify multiple next hops that the router can try.

Here is a URL and the command needed to do this verification process mentioned above.

set ip next-hop verify-availability

http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/ip_c/ipcprt2/1cdindep.htm

Hope this helps,

Don

New Member

Re: Policy based touting

Hi

I still not understand that why cisco docs says

The next hop router specified in the set clauses must be adjacent to the policy router, sharing a subnetwork with the policy router.

Also it is mentioned that CEF should be disabled on interface running PBR

Regards

Raza

New Member

Re: Policy based touting

Hi

Can any one tell how can I use BGP QOS in this enviroment especially when my next hops are on diffrent router but witin same As

Regards

Raza

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