Packet flow for voice between endpoints.

Unanswered Question
Jul 2nd, 2010
User Badges:
  • Green, 3000 points or more

Hi all -

Im trying to grasp the concept of how packets for voice traverse the network for this scenario:

- Hub location with CUCM cluster

- Remote location with PSTN H323 to CUCM

- Remote location SIP Gateway with SIP endpoints

- Incoming call from PSTN routes to CUCM---Route Pattern to SIP Trunk to SIP gateway at Remote location

Question, does the RTP traffic flow the entire path on a PSTN call or will it flow from router to router and signalling will flow through CUCM (keeps track of the call).


  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (1 ratings)
Brandon Buffin Fri, 07/02/2010 - 10:52
User Badges:
  • Purple, 4500 points or more

RTP flow will be between the endpoints (gateways) unless you are using an MTP.

Hope this helps.


Tommer Catlin Fri, 07/02/2010 - 11:47
User Badges:
  • Green, 3000 points or more

Ok, so if I have MTP configured in CUCM, then the RTP packets will flow through the trunks.   Trying to calculate my bandwidth requirement for this scenario.   I may try and put dial peers between the routers and a SIP trunk between the routers.... not sure yet.

Thanks much!

Brandon Buffin Sat, 07/03/2010 - 06:57
User Badges:
  • Purple, 4500 points or more

Right, the MTP anchors the call so that the RTP flow goes through CUCM instead of endpoint to endpoint.


Tommer Catlin Mon, 07/05/2010 - 21:50
User Badges:
  • Green, 3000 points or more

Thanks Brandon.  The MTP is what I missing on where it anchors or not.



This Discussion