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New Member

Cisco's 3661 Capable of handling 12 E1 Voice channels?

I would like to propose to an ISP client to use Cisco3661's with a total of 6x NM-HDV-2E1-60 2-port E1 Voice cards into each chassis. This mean that the Cisco3661 will be fully populated with 12x E1 VoIP gateway ports each.

Is this a workable solution?

Should I rather propose the more expensive AS5350's or AS5400's?

New Member

Re: Cisco's 3661 Capable of handling 12 E1 Voice channels?


On a similar question to yours with T1s, it was suggested to me that a 3660 chassis would likely not handle being fully loaded with all voice channels active. There seems to be no "quotable" answer to this question, as many configuration options can make a difference such as weather certain features are being used such as compressed voice (G.729 vs G.711), LLQ, RTP priority, etc.

I would say the best advice is to test your setup in a lab environment if possible to see where your config crosses the line. I believe that CPU utilization will be what would make the config impractical, not a hardware capability issue, other than not knowing off the top of my head how much bandwidth you will need on your fast Ethernet port to accommodate 360 simultaneous calls through the E1s. Quick calculation says approx 29 Mbps running G.711.

I would ask your Cisco SE how comfortable they would be with your config if you split the number of E1s over 2 3660 routers. You could also sell that config as having fault tolerance in the face of a chassis failure.


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