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Which solution for IP call from Telepresence endpoint?


We are struggling with choosing the best solution for dialing IP address from a telepresence endpoint registered on the CUCM.

As Unified CM cannot dial out to IP addresses, but the VCS can, we found 2 solutions:

  1. use a prefix to route calls using that prfix to the VCS-C through the SIP trunk on the CUCM.
  2. double register all endpoints as SIP endpoints on the CUCM and H323 endpoints on the VCS-C

Option 1

It is the one described in the [Cisco TelePresence Cisco Unified Communications Manager with Cisco VCS (SIP Trunk)] deployment guide.

See page 47

Option 2

It is to register both Telepresence endpoint as SIP endpoints on the CUCM and H323 endpoints on the VCS

example: on the CUCM and on the VCS

  • On top of the CUCM being setup in Configuration > System Configuration > Provisionning,
  • H323 Mode is set to on in Configuration > System Configuration > NetworkServices
  • And the VCS is setup in Configuration > System Configuration > H323 (with

Dialing ip address 12.3.456.7:

option 1 dial sequence if 7 is the prefix for IP dialing: 7012003456007

option 2 dial sequence: h323:12.3.456.7

Pros & cons:

I find the option 2 way more user firendly. Most user will never understand the add of the "0" in front of the IP address. Option 2 is much more user firendly

However with option 2 IT has to manage double registration.

We are wondering:

  1. If Cisco has a preferred recommended method and if yes, why?
  2. with option 1 can we only place SIP calls to IP address?
  3. if the VCS-C interworking is setup so that it can work as an H323-SIP transcoder, will the VCS
    1. convert SIP to H323 in option 1 if the called endpoint is only a H323 endpoint?
    2. and convert H323 to SIP in option 2 if the called endpoint is a SIP endpoint?
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