How to reroute traffic if PBR destination fails, and does exist in routing table

[Jeff Bankston]

Greetings. I have a client whom has the primary link to the internet on one gateway with static IP, and a second ISP connected via a second gateway whose connection is far, far faster than the primary link. This second faster link is cable modem on dynamic IP. A route map is created that, if the specific protocols and source IP matches on a core router one hop up from the ISP gateways, then route this matched traffic out the faster second ISP.

This config works fine, inside users are very happy to have the faster link, client is happy to have the cheaper faster ISP connection.

But, and there's always a but, if the cable connection to the faster ISP goes down, but the second ISP gateway remains operational, the PBR causes matched traffic to fail and NOT reroute to the slower ISP on gateway 1. I am using object tracking out the faster ISP on cable modem, so track shows down when this condition occurs.

So, how can I negate PBR when the cable modem error/failure condition occurs, and get all traffic (including matched) to go out the slower gateway 1?

Thanks, Jeff

[Jon Marshall · Accepted solution]

Jeff

Just to clarify.

You are using tracking but have you tied this into the PBR with the "verify-availability" option when you set the next hop in the PBR configuration ?

Whether that option is available depends on what device/IOS you have running.

What exactly is your tracking doing at the moment and what device are you running PBR on ?

Jon

[Jeff Bankston]

I am using object tracking to alter the default route out of that gateway 2 and inject it back to the gateway 1 ISP. That isn't having any effect, it appears that PBR is an absolute mechanism that has no means to reroute.

Unfortunately, the client is running Cisco 3825 12.4.24T7 and the verify command isn't available.

-Jeff

[Jeff Bankston]

Just figured it out, had to back up IP SLA into the core router where the verify command was available, and now PBR dymanically switches using the set ip next-hop command.

-Jeff

[Jon Marshall]

Jeff

Good to hear and obviously just ignore my last post :-)

Jon

[Jon Marshall]

Jeff

Apologies for asking what you have already answered but are you sure the option isn't there ?

I have just checked the 12.4T command references and it suggests it should be -

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_pi/command/iri-cr-book/iri-cr-s1.html#wp1167726580

Jon