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policy routing in FR

I have two PVC connecting to two branch.

I use policy routing to make Telnet protocol to pass

PVC1 et FTP protocol to pass PVC 2.

When PVC 1 is down, I would like Telnet protocol to pass through PVC 2.

How can I do this.


Community Member

Re: policy routing in FR

This should happen automatically, since in the absence of policy routing, the standard routing tables will be consulted. Make sure you have two routes to the remote subnet and it'll work.

However, please allow me to suggest an alternative to what you're doing. I believe your goal is to have a GOLD and a STANDARD path for providing better service to certain protocols or applications. Creating multiple FR paths may not actually work as well as you think, especially if your/your customer want to add more classes in the future. Chances are you may have routing protocols enabled. If you want the failover you mentioned to work, that means running the routing protocol on all paths. That's wasted bandwidth.

Second, what happens when the FR path gets congested and has to start discarding? You have no guarantee that it'll discard data over routing protocol information, and that could lead to flapping.

Also, I've tested this type of setup in a lab environment to prove a point. The FR infrastructure vendor used a common input buffer at the remote end. That means that all your PVCs come into one buffer, so your ftp could still have negative impact over your higher grade traffic.

Have a look at Cisco's CBWFQ (Class Based Weighted Fair Queueing). With this you can match traffic to access lists (which can match source IP/port), IP precedence and other sources of info. You can then guarantee minimum bandwidths for each class of traffic, on a per-interface basis.

This is cleaner, faster and much more versatile than using multiple FR paths.

Email me if you would like more information.

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