Policy Based Routing and Next Hop IPs

[Chris Pohlad-Thomas]

I notice when working on my PBRs that it will let you set multiple next-hop IPs. Are these for redundancy I assume? For example, if I have it setup like this:

set ip next-hop 4.2.2.1 4.2.2.2

will it try the 4.2.2.1 and if the interface that is connected to doesn't work it will try 4.2.2.2?      

[mfurnival · Accepted solution]

Hi Chris,

"If the interface associated with the first next hop specified with the set ip next-hop command is down, the optionally specified IP addresses are tried in turn"

From this document:

http://www.cisco.com/en/US/docs/ios/12_2/iproute/command/reference/1rfindp2.html#wp1020776

[Chris Pohlad-Thomas]

Thanks for the info! I might also think about using an SLA type configuration like in this document:

http://www.cisco.com/en/US/tech/tk364/technologies_configuration_example09186a0080211f5c.shtml

[paul driver]

Hello chris,

FYI - for resiliency with PBR, if the next hop  interfaces are unreachable the policy will still try to forward  traffic based on the match statements and start arping for the next hop  address.

Applying the set ip next-hp verify-availability command  into the polciy will make the router do a cdp lookup for the next-hop address  before policy routing and if its not found the router will route normal instead

.

res

Paul

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