SIP Trunk between CME and 3COM VCX

Unanswered Question
Oct 22nd, 2008

Does anyone know if SIP trunking is possible between a 3COM VCX gateway and either a CME or CUCM system? I know the 3COM VCX supports SIP trunking, but as most of us know, supporting SIP and actually getting such things to work are 2 different things.

If anyone has any input, it would be appreciated.



I have this problem too.
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marknigh1 Mon, 10/11/2010 - 09:09


Did you get this to work? If so, can you share what version of CUCM you are using and what non-default configuration you used on the SIP trunk? I have a project where my customer would like to integrate their VCX to CallManager for 4-digit dialing between systems. I haven't been able to find anything on this possibility?

Thanks for you reply.

dksingh Mon, 10/11/2010 - 09:21

Don't think we have formally tested SIP trunking between 3COM VCX and CME/CUCM.

But that does not mean that the two does not interoperate.

I have worked on atleast two customer issues involving SIP trunk between 3COM and CME.

You may need a few tweaks here and there but since both are standards based, there shd

not be any major surprises. My suggestion would be to watch out for IOS defect CSCsr37306

and make sure you are running IOS ver 12.4(20)T3 or 12.4(22)T1 or later.

For interoperability with CUCM, we recommed using a CUBE between the two.



marknigh1 Mon, 10/11/2010 - 09:25

Thanks for the information.

Would you suggest doing h.323 to CUBE and then SIP so that the voice gateway is setup as a h.323 gateway in CUCM? Or have CUCM do a SIP trunk to CUBE and of course, SIP to 3com?

Thanks again.

dksingh Mon, 10/11/2010 - 09:33

My choice will be to do  h323 between CUBE and CUCM as its a

more mature standard and has been around for a while.

With SIP, different vendors implement the standard differently as

it is open to interpretation so there are always knobs and tweaks


Having said that, since both IOS and CUCM use common SIP

stack, you can keep both legs the same..aka SIP end to end.

Good Luck.



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