EIGRP Reliability Metric

[bhoward]

I am looking for info on the reliability metric in eigrp. I am looking for a way to take a link out of service if it is flapping or degraded service. The ip event damping feature would work, however the link doesnt always go down. How does the reliability metric change, I know it is based on keepalives, but over what time frame?

[paul.werner]

I think what you seek may be found here:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t13/ftipevdp.htm

A couple of notes/thoughts on the matter. From my perspective, this is not a cure for a specific problem, rather it will treat certain annoying symptoms. What is probably better OTOH, is to determine the underlying source of the link flapping. Is this interface frame relay, ISDN, Asynch, leased line, X.25, or something else? Has the underlying cause of the link flapping been troubleshot?

pw

[bhoward]

Paul, thanks for the reply. I am in a difficult situation because the customer owns control of the network. They have an Avaya IP call server that will not go into Local Surviability Mode (SRST) unless it loses registration for 5 minutes. The problem is the link becomes degraded (verified by ISP) but doesnt actually flap. This causes major problems with their voip. I wanted a way to take a bad link down for at least 5 minutes so it would switch to Local Survivable Mode. I was thinking of using the Reliability metric with a route-map to match on metric after it becomes less desirable with the reliabilty, then set next hop to a null interface so it would lose registration. They would have to manually switch it back, but once in LSP mode they manually switch back anyway.

I am not sure what increments the reliabilty metric? Or if there are any better ideas on the issue.

Thanks for your help...

[kleo]

a couple things first: shorten the timer on the avaya gateway to 1 minute ( the minimum), by changing the MGC timers in the avaya gateway.

Second,

You can disable ethernet via software in the gateway or manually pulling the ethernet connection from the avaya gateway. that would force going to LSP mode.

Also, if your running the newest avaya CM software there is a way to force all calls to go over PSTN and just leave signaling over IP network.(which doesn't care about jitter, packetloss, etc) It is called a forced IGAR. Also, with newest version of LSP you can set it to automaticlly switch back based on network performance stats and call states.(your choice)

here's some good documents on IGAR and Dynamic CAC.

http://support.avaya.com/elmodocs2/g350/GW_DCA_%20IGAR_MDB.pdf

http://support.avaya.com/elmodocs2/comm_mgr/r2_2/pdfs/233506_9.pdf

[paul.werner]

The posts above seem to be more in line with fixing the root problem than treating ancillary symptoms. I do not have any knowledge of avaya gateways however, what is written above seems to make logical sense and is backed up by supporting documentation from the vendor. It seems to be a worthwhile course of action. let us all know how it turns out.

pw