CUCM 9.1 calls from sites

[Ali Bahnam]

Dears,

I have a CUCM 9.1 installed on HQ abd I have sites the connected via site to site VPN with HQ only (The site are not connected together only with HQ).

I configured phones and registered the to the HQ CUCM and I call do calls between the HQ and the sites. The issue that when I tried to call between the sites itselves the phone is ringing but when answering we cannot hear the voice from the both ends.

I configured a site to site VPN between two sites everything works normally I can do a calls between the connected site (VPN).But if I have 10 sites in this case I have to do a site to site VPN between all the sites.

Appreciate your supports,

[Dragan Ilic]

DMVPN or full mesh for this to work...DMVPN is definitely more elegant approach...

HTH,
Dragan

[Ali Bahnam]

Hi Dragan,

For another client I have the same topology but they have a CME insted of the CUCM and everything working normally, so why if we have a CUCM we need to do DMVPN??

[Dragan Ilic]

Well, because you are using centralized CUCM system for all of your phones and all of your branches have vpn tunnel only to HQ and not to other branches.

In case of CUCME you have a number of separate systems working on their own CME system and probably you have different routing concept at other customer.

I don't know much about your environments so can't comment more...but as I said only solution for your CUCM based solution would be DMVPN or more complicated full mesh...

HTH,
Dragan

[Ali Bahnam]

ok but the sites phones are registered to the CUCM so when I do call between the sites the CUCM will open a Tunnel between the phones (the CUCM can ping the phones of different sites) this what I understood

[Dragan Ilic]

CUCM can ping phones at branches because of existing vpn tunnel from HQ to every branch.

And CUCM can't open a tunnel between sites - cucm will do signaling between phones on different sites but after call setup phones speaks directly to each other so you must have a proper routing for that. In your case - proper vpn tunnel...

That's why you hear ringing but no voice - when it comes to directly speak of voice you have no vpn for that...

HTH,
Dragan

[Ali Bahnam]

Sorry, but why it is working for CME (no need to setup vpn between the sites)

Can you expalin me please??

[Dragan Ilic]

i can only give my opinion:

on cme you are using dial-peers with "session target..." command and for that target you have functional routing - ie you can actually reach that destination on L3. That's the reason it's working...again I don't know your environment.

Check your routing in details on CME setup and your CM setup - they are not the same 100%. There you will find why this is not working.

You don't have VoIP problems there - you have routing problems and you must solve completely routing and after that voice is going to work just fine...

HTH,
Dragan