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Community Member

Finding the alternate path in routers

I work in network capacity planning. I need to know if backup links exist for a particular primary link if its utilization begins to increase. Often times, this information is not readily available.

I want to know if there is a way to find the alternate path to a particular network without bringing the primary path down. For example, I log into a router and do a 'sh ip route' to a particular network or device. This command will show me the next hop of the best path. Is there a way to force this command to look at the 2nd-best next hop, and show me that one instead.




Re: Finding the alternate path in routers


you have got any dynamic routing protocol being run in your network ?

and whts the kinda of connectivity between your locations ?

is it something like hub n spoke or fully meshed or partially meshed ?

is it possible to post out a symmetric figure of your current setup ?


Community Member

Re: Finding the alternate path in routers

The network is running a dynamic routing protocol.

There are all kinds of connectivity ranging from below T1 speeds and up.

The network is a good size, with various configurations in different locations.

Certain areas of the network are designed with primary and backup links. For financial organizations, the primary and backup links must be geographically dispersed for disaster recovery purposes. For network capacity planning, I need to know whether a particular link has a backup and what that backup link is.

That information is not readily available to me. I want to know if there's a way in Cisco routers that can tell me what the alternate path would be if the primary link went down using dynamic routing. I can either have the link brought down and see where the traffic re-routes, or I can simulate the network in OPNET or some other tool and do a failure analysis.

In my area, neither is easily accomplished. I am hoping that Cisco has a way of looking at the alternate path to a particular network.

For example, EIGRP has a database (feasible successor) of the best path in case the primary path fails. Is there a way for me to do a 'show ip route' against this database instead of the successor database if I am running EIGRP?

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