Incoming Call flow in cucm

[Yenosh]

Can any one please explain the incoming call flow in cucm?

ex: If I dialled office number from my mobile, how the cucm send the call to office phone

[MOHIT SINGH]

Hi Yenosh,

It depends how your setup is but normally an inbound call flow will be as below

Mobile --> PSTN network --> ISDN PRI line --> Voice Gateway --> MGCP/SIP/H323 --> CUCM --> IP Phone

Normally ISDN PRI have a range of DID numbers that will be assigned to IP phones. If a mobile user wants to dial an IP phone they dial the DID number of the IP phone user. When DID is called from mobile it goes to voice gateway over PSTN which then sends the call to CUCM over any of the protocol configured (SIP/MGCP/H323). On receiving the call CUCM checks the called number and delivers the call to the IP phone with the assigned dialed number.

[Yenosh]

Hi Mohit,

Thanks for you reply!!!!

I would like to know, how the cucm comes to that which partition contains the called number.

For ex: We dial a number 575-673-XXXX, it came to cucm after that how cucm find this number is in this partition.

[Jaime Valencia · Accepted solution]

Suggest you do some reading on the topic:

https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/srnd/8x/uc8x/dialplan.html

[jijesh.kt@brambles.com]

@Jaime Valencia 

Can you please provide more details.

When somebody dialed the office number from mobile. call is coming via service provider line it is hitting into the voicegateway. Voicegateway what will do ? Is there any translation happening when the pattern configured in Gateway.

[HARIS_HUSSAIN]

1) Each Device Registered / Integrated with CUCM will have CSS which will determine the partition for the Same.

Below video will be helpful

https://www.youtube.com/watch?v=AiwdWkS0Fkw

*** Please rate helpful post; Mark "Accept as a Solution" if applicable

Thanks,
Haris