TDM forwarding capacity of a 3900 series router

Unanswered Question
Oct 3rd, 2010


  Does anyone have any figures on how many E1/T1 we can safely terminate on a 3900 series router?

With 3800 series routers we have seen any more than 6 pushes the processor above 90%.

Many thanks

Adam Clark

I have this problem too.
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clark.adam.p Sun, 10/03/2010 - 19:22

Thanks for that,

  Reading off the data sheet for the 3800 is what got us into trouble the first time.

To terminate and move a call to the IP environment, the ISR needs take the PSTN call, turn it into a packet and send it, which is a software task and is not hardware assisted.

The raw throughput of a device is not representative of TDM termination.

I am looking for anybody that has tested this in the real world.

Many thanks


Paolo Bevilacqua Sun, 10/03/2010 - 23:01

For high density T1/E1 voice termination you do not use the ISR router but the AS5xxx

VGs, that are designed and certified for 20, 30 circuits and more without problems.


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