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Redundant link config

I have 2 MPLS circuits. Second I want to use as backup.

Is there any way of making second wan link as backup even if the first link is up but has high latency, on first link I get 200ms response time, but sometimes in case of service provider problem it goes more than 250ms. Now the first interface is up, still I want to switch to second link.

In normal backup config it wont switch over unless line protocol is down. Any way to switch over depending on response time of the link, any MPLS feature, any routing protocol feature (I have EIGRP, BGP) ?

3 REPLIES

Re: Redundant link config

Hi,

I dont think there is any provision to track the response of the link to fall back to a preferable path.

Even though EIGRP uses composite metric like delay , it is not dynamic in the sense that the delay will not change unless configured

Narayan

Re: Redundant link config

Hi,

I think Cisco Optimized Edge Routing (OER) could be useful for you. Have a look at:

CISCO OER PREFIX POLICY EXAMPLES

In order to provide a better understanding of how Cisco OER utilizes prefix policies, here are two examples of the policy algorithms in action:

Example 1

The customer has configured a policy that requires a maximum of 50-millisecond delay round-trip time for voice traffic. The current measured delay is 40-milliseconds, so the prefix is said to be "in-policy."

Useful links:

Cisco Optimized Edge Routing Deployment Guide

http://www.cisco.com/en/US/netsol/ns471/networking_solutions_white_paper09186a008022dbfa.shtml

Cisco Optimized Edge Routing Broadband Deployment and Configuration

http://www.cisco.com/en/US/netsol/ns471/networking_solutions_white_paper0900aecd80243f70.shtml

Primary and Backup WAN Links Using Cisco Optimized Edge Routing

http://www.cisco.com/en/US/netsol/ns471/networking_solutions_white_paper0900aecd802b8e68.shtml

Hope this helps! Please rate all posts.

Regards, Martin

Gold

Re: Redundant link config

You may also be able to get this accomplished using the new tracking options in the policy routing.

This is a link

http://www.cisco.com/en/US/products/sw/iosswrel/ps5207/products_feature_guide09186a00801d1e95.html

It does not appear to be as robust as the track option in the HSRP that can look at "over threshold" but you should be able to set the RTR ECHO timeout to a short value and it should appear unavailable.

These new SAA features are on my list of things to play with in my lab when I get some free time.

>>>> the more I think about it this will not acomplish what you want since it is outbound only and does not effect the routing.

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