Traversal and non-traversal calls

[jacinto1m]

Hi,

Can somebody explain in simple words what are traversal and non-traversal calls?, what is the difference? And also Does the VCS control below need traversal licenses?,

CTI-VCS-CONTRL-K9

VCS Control

Thanks in advance.

[RICHARD MESSINGER]

Which is used when a endpoint is registered to a VCSc and the call is going to a Video phone or other audio endpoint that is registered to a Call Manager and we have a SIP trunk between the VCSc and the Call Manager?

I am guessing it would be a Traversel license seat.

[gubadman]

It depends a lot on set up. In our test labs they are usually non-traversal as the VCS is not taking media, just the signalling.

Thanks,
Guy

Sent from Cisco Technical Support iPad App

[Tomonori Taniguchi]

> Which is used when an endpoint is registered to a VCSc and the call is going to a Video phone or other audio endpoint that is registered to a Call Manager and we have a SIP trunk between the VCSc and the Call Manager?

As Guy mention, this is very depend on configuration but main factor is search rule and priority.

VCS always try to setup the call with native call protocol first then fall back to interworking call but this will be following search rule priority as well.

If call establish via UCM (over SIP trunk), then call most probably establish as non-traversal call unless encryption policy is enabled on VCS (then call will go through B2BUA on VCS and treat as traversal call).

If call establish with Endpoint on VCS, then it depend on configuration and far end device registration protocol.

[Dany Daoud]

If you have 0 non-traversal license will VC calls work for instance using jabber ?

[Tomonori Taniguchi]

One VCS Expressway, VCS will use traversal call license to handle non-traversal call, if required.

For example, VCS-E has no non-traversal call license or already use all installed non-traversal call license with

existing active call, the new incoming non-traversal call will handle by consuming traversal call license (instead of disconnecting it because of non-traversal call license availability).

Please note, this is not true on VCS Control.

VCS Control will not handle non-traversal call by using traversal call license.