Dedicated WAN Bandwidth Requirements for SIP Trunking

[madhav.kumar.bhardwaj12]

Can anyone share doc which talks about WAN ( MPLS) bandwidth requirements for SIP trunking projects for Centralized deployment . We are thinking to use G729 codec with Vendor and assuming around 500 channels for SAPAC location. According to G729 codec, it will require around 20 Mbps ( Glod CAR) for 500 sessions. 

Then we have to think about Centralized site which is 1 and around 40 remote sites .  For remote site, i think calculation will be same, 40 kbps * number of calls at a time. Do we need to include both external and internal calls bandwidth for remote sites ? So calculation will be like -40kbps * ( Number of internal and external calls at a time) ? Correct ?

For Central site, it will be same 40 * ( Number of internal and external calls at a time) ? I think we need to think about double of this bandwidth as remote site external calls will be going through Central site and will use same Pipe to call Outside so bandwidth needs to be double ? Correct ?

Please let me know if i am forgetting to included any other factors ? Any reference doc or already prepared business case will be helpful. 

[Mohammed al Baqari]

Hi,

This will be interesting project. I went through this couple of times and its very interesting and challenging.

Collaboration SRND is the way to go. They have very good illustrations and equations for bandwidth calculation for deployment each model. Also, the have good section in SRND for signaling bandwidth requirements. I am pasting below links for the required chapters.

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/srnd/collab10/collab10/netstruc.html#24007

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/srnd/collab10/collab10/models.html

Also, if you are going for endusers deployment I recommend to read about Erlang B and use online calculators. For uccx deployments you need Erlang C.