Campus Routing question

[jjjwinkler]

There are three campus buildings connected via routed laser links (100Mbit Ethernet). There are several days within a year, where fog disrupts the communication. We have installed a routed WLAN-Bridge solution for backup. EIGRP is used as the routing protocol with load-balancing over unequal cost-paths.

The problem is, that clouds of fog enable or disable the laser links short-term and in this times there is an continous route flapping. Is there a possibility to adjust timers or intervals of EIGRP to avoid using the "laser-route" until the link is stable for a while?

[DALE FRANCIS]

There is not a lot one can do with EIGRP timers except hold-downs and hellos for interfaces, the only thing i can think of is make the SIA timer low with timers active 1, so that if no reply gets through then route will go SIA, this however is not a proper solution.

Sorry i cant be of more assistance but EIGRP is proprietary and closely kept by Cisco.

[vkasacavage]

Instead of using unequal cost load balancing, you could setup the WLAN as a backup interface. Doing this would allow you to set a delay interval between the time the laser goes down and when to make the backup active

[jjjwinkler]

The solution - in my case - has been to use the "dampening" command of the IOS (actual only available on 7xxx and above platforms), which allows to restrict flapping interfaces from being inserted into routing table until the link is stable again (configurable values). It works.