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Walkthrough Wednesdays
Kim Nielsen

Cucm 8.5 and Skype SIP trunk


I'm trying to get Skypes buiness SIP trunk to work with an CUCM 8.5. I get the idear on how is should work if I set it up on a voice gateway, but is it possible to get it to work directly on the the CUCM 8.5?

Anyone gotten it to work there, and if you have, could you give some pointers on what I should remember to setup?

Saurabh Agnihotri
Cisco Employee

As far as I know, you can't have it working with CUCM directly as CUCM does not support "SIP Register" or sending outbound options for keepalive.

What you would need here to have it working would be a CUBE. You need to have a SIP trunk from the CUCM to the CUBE and another SIP Trunk from CUBE to Skype.


Saurabh Agnihotri
Cisco Employee


Cisco Employee

Hi Kim,

It depends upon provider to provider. Some Service provider does not require registeration of the device .For those provider you can directly create a sip trunk from the call manager pointing it towards the service provider under the destination ip address of the sip trunk.

but I had deal with skype directly with couple of customers , they requires registeration which call manager does not support hence you need to use the CUBE (IP-IP Gateway) and use registeration commands under sip-ua

This question has also been discussed at the skype forums if you want to take the look


Please rate if you find this info useful.



Thanks for the help both. It seems that I will have to setup an CUBE to get it to work. Were hoping that I didn't need to do that.


Hi again,

I have now a working SIP trunk running up against Skype. So you don't need to have the CUBE to get it to run on CUCM 8.5.

I had some of the other guys to talk with Skype over a chat, so I don't know if skype changed anything in their end, but I don't think so.

But you need to setup Skype for IP authentication.

On the CUCM 8.5 you need to setup the "SIP Trunk security profile", "SIP profile" and the SIP Trunk. Normal setup there, with default most of the way.

To simplyfi what you need to do, then under the SIP Trunk configuration, there you have the "Outbound Calls" where you need Caller ID DN to be your Skype user ID.

Under "SIP Information" you will need to setup the destination Address.

From Skype you will get the info that the destiantions is somefhing like: and

That will not do, because this will be sent to skype with the invite, where skype only accepts "".

So if you use then it will go well. and etc etc is only proxier or something like that. So it will work with only using as the destination address.

You could probaply also make a SRV, and get it to work that way.

Under the SIP Trunk security profile, there you need to choose "non Secure" device security mode, TCP+UDP as incoming transport, and UPC as outgoing.

I set the X.509 Subject Name as the Sip user ID, but I'm not sure that you need to do that.

Anyhow it is possible to get it to work directly on the CUCM 8.5 without the CUBE.


Does it work for inbound too?

Hello, I am interested in this configuration. Does it work for inbound and outbound calls? Is it stable?


Kim Nielsen


It works for both inbound and outbound calls. At the moment we are still testing. The customer has only added 1 public number to the account. Our plans is to forward the their public numberplan to this number as a start.

But is should be possible to transfer your public numberplan to skype in the end.

We haven't tested the trunk so much just yet, but it seems stable.



Anyone make and testing this trunk on other CUCM versions? On the 7.1.5 for example..

Hello Kim:

It almost work for us with CUCM 8.6, but there must be some signaling or detail I am mising.

Can you screenshot your SIP trunck, Sip Security and Route Pattern configuration hiden confidentilan information?

Thanks in advance,

Marvin Mejia

Hello Kim

Hope you are well?

I'm trying to setup my CUCM 9.0.1 with Skype Connect and I'm really struggling to get this working.

I don'tsuppose you have a document/screenshots that show  the configuration that you used to get this working?

I know this discussion was a couple of years ago, but I cannot find any documentation which talks you through the configuration required.

Kind regards


Euan McGregor

Hi there, this is also of great interest. Has anyone managed to get this fully configured and can post a sample config for CUCM 8.5?

many thanks,



Hi everyone.

This summer i'm planning integrate our CCM 8.6 with sisky.

Maybe it helps.



I have a customer who has just asked about this.

Can you please post up your config as requested by Marvin & Euan, as would be much appreciated.



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