Hello there,

According to ,https://lists.kamailio.org/pipermail/sr-users/2016-March/092058.html, which talked about  B2BUA (just signalling) in Kamailio.

As i have experienced working with SEMS, freeswitch and Kamailio while using B2BUA feature, Each of them have pros and cons:

1- The sems is a light sip engine server with several applications (like as sbc) for using b2bua. All incoming and outgoing calls could go to sems server for doing b2bua like this:

Incoming<=======>Kamailio<========>Sems<========>Kamailio<=======>outgoing

2- In sems, you could disable rtp realying. It forces sems to work just as b2bua without anchoring RTP

3- Easy to use different active profiles in routing.