voip call flow -traffic

[erinedison]

Hi Team,

I am new to VoIP and trying to understand the traffic flow

can anyone please explain the traffic in the below scenario-Multisite WAN with centralised call processing

MainSite A has the cucm and connected to sip provider

remotesiteB conected to siteA by WAN

siteB has 20 ip phones.siteA has 150 ip phones

calls from siteB internalphone(eg,ext:5001) to siteB internalPhone(ext:5002),how does the traffic flow ?

for each internal call (between extensions )in remote siteB,does it have to take the WAN part to connect to CUCM to process the call?

traffic flow ?

siteB5001 >siteBVoIP gateway router> .......WAN.............> siteAVoIP gateway router >CUCM > siteB5002 ?

or,

siteB5001 > siteBVoIP gateway router > siteB5002 ?

Please explain,

Thanks

Erin

[Terry Cheema · Accepted solution]

You need to understand for every call - there is signalling and the actual RTP payload.

For internal calls i.e Site B to Site B, the signalling traverses the WAN as phones are registered to CUCM (which is across the WAN at Site A) but the actual RTP media flows directly and doesn't goes through the WAN connection.

Gateway is not involved here, call doesn't need to go to voice gateway. Gateways are only involved when your calls are going out of your network so as long as it stays inside your company the calls do not go through the voice gateway.

A to B - Signalling/Media over WAN

A to A - Signalling over WAN/Media or Audio stays on LAN

Any phone to PSTN (lets says you call your mobile) - Here the call goes through the voice gateway.

Let me know if you have more questions

-Terry

Please rate all helpful posts.

[erinedison]

Thank You so much for the great explanation.

Erin

[Terry Cheema]

Not a problem Erin, glad that helped. Please do rate all helpful posts and mark the thread as answered if you have no other questions.

-Terry