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New Member

Traffic using Fast Ethernet, not T-1

I have two routers at location A. They are connected via a Fa interface. Router A1 has 4 T-1s in a Multilink interface to site B. Router A2 has 1 T-1 to router at site C, which has a T-1 to site B.

My problem is when sending to site B, it always choose the Fa interface rather than the multilink interface.

What is the best way to direct traffic for B over the multilink?

I'm running EIGRP on all the routers.

New Member

Re: Traffic using Fast Ethernet, not T-1

I've attached a drawing of the network.

When I trace from A1, it goes...

1 - A2 via Fa

2 - C via serial (T-1)

3 - B via serial (T-1)

I'd like it to go

1 - C via multilink2

Hall of Fame Super Silver

Re: Traffic using Fast Ethernet, not T-1


There are a couple of things that could produce the symptoms that you describe. First I would check to verify that the multilink is being advertised in EIGRP: does router A1 see router B as a neighbor and does router B see router A1 as a neighbor? Does either router have a passive interface statement that could affect routing? Does either router have a distribute list that could affect routing.

If the multilink is working and routes are being advertised over it then it implies that the router is choosing the path over the T1s based on metrics. Check all of the interfaces and see whether the multilink has a quite low bandwidth or a very high delay and check the T1s for their bandwidth and delay parameters.

If that has not given us the answer then perhaps some more detail from the routers might help us. Could you post the output of show ip interface from each router? And maybe the output of show ip protocol?



Re: Traffic using Fast Ethernet, not T-1


I did face a similar problem in my network.

The solution to this is to manipulate the metrics and i would suggest the use of delay for this.

Also i would like to add the bandwith command under the multilink interface.

let us knwo if it works fine