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Load sharing

I have 2 2610XM routers ! Each with a WIC2T card and extra Ethernet port! My aim is to connect the routers in two ways.

1.. 2mb Serial connection through the Serial cards ! set as the primary link.

2.. The extra ethernet card will be connected to a Xylan ethernet network speed approx 2 Mb ( Xylan link justlike connecting routers back to back ! ) this will be set as the secondary link!

I would like to configure the connections in either of 3 ways if possible?

1.. Serial is main link and Xylan Ethernet takes over if serial fails!

2.. Serial is main link and if usage exceeds 75% then ethernet link kicks in and takes some of the load.

3.. Bothe lines are share the load giving effectivly 4MB

Now I amsure this could be done with 2 serial likes but can it be done with a serial and an ethernet connection ?

Hall of Fame Super Silver

Re: Load sharing


If you run a dynamic routing protocol on both routers (and run it over these two links) then either alternative 1 or alternative 3 should be pretty easy. There may be some way to achieve alternative 2 (at 75% shift some load) using some of the traffic engineering features, but I am not aware of a simple way to achieve this.

Alternative 1 (use serial as main link and use Xylan as backup) is easy with a dynamic routing protocol (EIGRP, OSPF, even RIP). Make sure that the metric over the serial is more attractive than the metric over the Xylan. The details of how to do that will vary depending on which routing protocol you use.

Alternative 3 ( use both links at the same time) can be achieved with a dynamic routing protocol. You will need to configure it so that the routing protocol sees both intefaces with the same metric. Then sharing load will occur. Again the details of how to do this will depend on which routing protocol you are running.

As a side note: it would be beneficial in several respects if the bandwidth of the Ethernet interface was a reasonable approximation of its real capacity (not the 10 Mb or 100 Mb that the interface would default to.) So for EIGRP or OSPF I would probably suggest manipulating the bandwidth of the Ethernet interface as the way to influence the routing protocol.