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New Member

Best way to connect SIP Trunking provider to CUCM

Hello all,

I have a SIP trunk from  I have dedicated an IP to it but now the questions is how best to connect it into CUCM 7.  I have a PIX 525 and a 3745 router.  I connect via ethernet to my ISP to their router (a c851) which I have NO ACCESS to. suggests that I purchase an Edgewater Edgemark ALG, but to my knowledge, my PIX 525 already supports those functions.  Is it possible for me to bring the SIP trunk into the PIX on an outside interface and then use CUCM with MGCP to control it?  How would I route calls to the PSTN through's trunk?  I have practically no experience with SIP so am very much in the dark here.  Currently I only have the 1 trunk for testing purposes but if it works out well, I plan to add several more.  I'm not sure what the best scenario is.  I know that does NOT use SIP registration.  Any suggestions on how to configure this are very much appreciated.  I've read documents that talk about configuring SIP on the ASA/PIX, but none of these mention anything in regards to dial-peers etc.  Do I need dial-peers?  I've configured those on routers for h.323 gateways, but again, I know nothing really when I coms to SIP, am still very new to this technology.  Any advice welcome.  Thanks again.  For what it is worth, I have multiple interfaces available on both the PIX and the router.


Re: Best way to connect SIP Trunking provider to CUCM

I would highly recommend reading up on Cisco's CUBE or even Acme Packet as you may find that, depending on the carrier, you may need to do some normalization of the SIP protocol.  Although SIP is a standard protocol - it is not a STANDARDIZED protocol - so different vendors can have minor variants in what they do with SIP.  The Cisco solution is CUBE.  Acme Packet is more service-provider oriented and, given your experience with SIP trunking, may be more than intimidating to deal with.  However, it's very powerful and is an alternative.

You can find info on the Unified Border Element (aka, CUBE) here:

You can typically run this functionality (with licensing, of course) on ISR routers (2800/3800/etc) and should be more than adequate for testing.  All in all, it ends up looking a lot like H323 IMO.


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New Member

Re: Best way to connect SIP Trunking provider to CUCM

Thank you for the reply.  I have done some reading up on CUBE, sounds like it is what I am looking for.  Will CUBE run on 3700 series routers?  From the documentation I read, I don't think it is supported.  I have 3745.  I have Advanced IP Services, 12.4-15-T8.  So on my original qustion, I would bring the SIP trunk into the 3745, and then how would I perform call-management?  Would I create several dial-peers as in h.323 but all voip?  Or pots/voip combination?  I guess what I want to know is once the call comes into the router via the SIP trunk, how can I direct it where to go at the gateway level, say to specific DNs, etc.  As far as I am aware, CUCM does not allow routing based on CallerID.  I apologize for sounding a bit ignorant, but as I said, this is quite new to me.  Thanks again.  Also, I have an SRV record for  With the inability to run CUBE, possibly an opensource solution such as asterisk?  I'm definitely unsure here.  Thanks again.

Cisco Employee

Re: Best way to connect SIP Trunking provider to CUCM

You can have CUBE on that router

I always recommend using this tool to look for an IOS with something you need, you can look for IOS based on features needed.

Software Advisor

This will give you an idea of how things look like when using CUBE

Unified Border Element (CUBE) with Cisco Unified  Communications Manager (CUCM) Configuration Example

You're correct, CUCM performs routing based on called number.



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if this helps, please rate
New Member

Best way to connect SIP Trunking provider to CUCM


I have seen you mention Acme Packet. Any recommendation I should read before choosing vendor?

I already know I am in a Cisco Web, but need to compare Acme Packet SBC to Cisco CUBE with all the view points.