Routing issues between Microwave and 827h DSL router

[dasberry]

The customer preference is to have the Microwave be the primary path. However when we activate the 827h, the system routes all traffic through the 827 thus causing routing issues going to specific points via the Microwave.

I have looked into the cost and perhaps utilizing delays as well as HSRP, and none worked to date. The network backbone is EIGRP and the network from this point to others is 10.x.x.x , 172.16.4.x/0.3.255, and 192.168.253.0. I would like to hear any ideas on how to make the MicroWave the primary and yet activate the DSL as the secondary?

[donewald · Accepted solution]

EIGRP can use local BW setttings on the interface to make a link be chosen over another. So, try setting the interface to the microwave link to a higher bandwidth (use the bandwidth <#> interface command). Or you can change the other interface to be lesser than the Microwave. Keep in mind you'd have to do like things for the return path traffic.

Hope this hels you,

Don

[dasberry]

Yes, I tried this and it appears to be working. Something that came to mind is the altering of the distances both internally/externally. That way should someone change the bandwith setting I'll this to fall back on and prevent the DSL from becoming the primary route.

[rbristow · Accepted solution]

dasberry,

Without looking at your particular topology, it sounds like you need to adjust some EIGRP routing metrics. This can be done in a number of ways. BW is the easiest, but if you have automated Performance tools that pull SNMP data from the routers, this can mess up utilization reports. And sometimes other people will come along and "correct" the BW statements for you. You can also adjust EIGRP metrics with the DELAY parameter on interfaces that you want to be less preferred, for example DELAY 10000 on each side the the DSL's circuit. Another way is to use an OFFSET LIST to adjuct EIGRP Metric calculations.

Regards,

Rob Bristow

AT&T Solutions

CCIE #3335

[dasberry]

Thanks for the response, I tried your suggestion with the Delay statementand for reasons not clearly understood it attempted to re-route all traffic through the DSL. Something that came to mind is the altering of the distances both internally/externally. That way should someone change the bandwith setting I'll

have this to fall back on and prevent the DSL from becoming the primary route.