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Community Member

Can I use a IMA T1 card over regular T1's?

I need to connect two sites with 4 T1's. I have two 3825 routers with IMA cards and I was wondering if I could used them for this application. The T1's are regular leased line circuits between the two sites, no ATM switches in the middle.

Has anyone done this before? I want to avoid using some other cards with CSU/DSU's.

Hall of Fame Super Silver

Re: Can I use a IMA T1 card over regular T1's?

Hello Juan,

it should be possible.

It is like a back to back connection in a lab with the leases lines in the middle.

You need to configure the same ATM PVC on each side for example


because no ATM switch is in the middle nothing can change the ATM VPI and VCI.

other possible tricks may be related to ILMI.

Only possible issues arise from delay differences on the different links if they are high.

Also be aware that other collegues have reported issues related to the IOS image they were using.

To be noted also that IMA has its own overhead to be added to ATM cells overheads in carrying IP packets.

So I would go with this solution only if you already have the IMA network modules in your routers.

if you have to buy them it is not the best solution for your scenario.

Hope to help


Community Member

Re: Can I use a IMA T1 card over regular T1's?

Thanks Giuseppe for your prompt response.

Yes, that is the reason I'm using these modules, it's what I have. Originally I was getting another type of circuit, but because I needed some type of connectivity to the remote site fast T1's were the only option. I'll run on these circuits for a few months until I can get the permanent circuits.

Thanks again for the tips.

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