CUCM Direct Connect With SIP Gateway

[mohdalhafiz85]

HI Cisco

May i have an advice regarding about CUCM integrate with SIP Gateway? Currently Service Provider want install CUCM for their customer. Its mean their customer phone directory number will register inside CUCM

Outbound Call from customer to PSTN will through CUCM then SIP gateway and for incoming call from PSTN will go to SIP gateway then CUCM . The call flow as per below

Outbound Call

Customer > CUCM > SIP Gateway > PSTN

Inbound Call

Mobile > PSTN > SIP Gateway > CUCM > Customer

Call between Customer - Customer 1 call to Customer 2

Customer 1 > CUCM > SIP Gateway > CUCM > Customer 2

Attach i had draw the diagram for this solution. Appreciate your advice for below question and the solution

1. Can i configure SIP trunk inside CUCM then pointing direct to SIP Gateway? Which is mean no need to configure CUBE

2. When Customer receive a call from PSTN, SIP gateway will be need configure to pointing the call to CUCM is it right?

3. CUCM will use private IP, how can customer reach CUCM? I may need to configure some routing is it?

[Marcelo Morais]

Hi mohdalhafiz85,

1.If the SIP GW is connected to the PSTN via a pots, then you are able to configure CUCM to point directly to the SIP GW ... it will be a voip call to CUCM and a pots call to the PSTN.

2. Yes, that's correct.

3. You need to guarantee that CUCM will be reached by the SIP GW and vice-versa. Remember that the customer will reach the PSTN, and the PSTN will reach the SIP GW via T1/E1.

Hope this helps.

[mohdalhafiz85]

HI Marcelo

Regarding about your answer for question number 1, actually i am not configuring cisco SIP gateway because the SIP Gateway will provide by Service Provider. The SIP Gateway product i am also not sure what type of product they use. The only i know it is SIP Gateway based on their information

The CUCM will install inside the Service Provider  Datacenter which is mean will connect to the CUCM directly to their SIP Gateway. As per below flow diagram.

SP Customer 1 (IP Phone) > CUCM > SIP Gateway (SP) > PSTN (SP) 

They will have many customer as per below flow diagram

SP Customer 1,2,3 & ..... (IP Phone) > CUCM > SIP Gateway (SP) > PSTN (SP) 

If the Customer 1 want to make a call to customer 2, the call must goes up to SIP Gateway (SP) then its route back to the CUCM because all directory number will provided by SIP Gateway (SP). Below is the flow diagram

SP Customer 1 (IP Phone) > CUCM > SIP Gateway (SP) > CUCM > SP Customer 2 (IP Phone)

1. The question is it possible this design can be works?

[Marcelo Morais]

Hi,

 this design is possible.

 The SIP GW (Service Provider) must be a CUBE to allow this VoIP to VoIP call (CUCM - SIP GW - CUCM).

 As soon as the customers (1, 2, 3, ...) are connected to the same CUCM, you must configure the CSS of a customer with no access to the PT of the other customers ... this way, you are able yo configure a Route to the SIP GW every time a customer x wants to talk to customer y (in other words, customer x - CUCM - SIP GW - CUCM - customer y)

Hope this helps.

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