Even for two subscribers in the same network behind the LANCOM VoIP Router, when connected to an upstream SIP PBX the media proxy generates data streams with separate media end points on the LAN side and on the WAN side (towards the SIP PBX).
In this case it is not necessary to pass the media streams through the upstream PBX, so the SIP signaling helps the LANCOM VoIP Router to make a new decision on the path to be taken by the connection data. Using the end points in the media proxy the data streams can be connected directly, making a diversion via the SIP PBX unnecessary.
This decision is also made again in the media proxy if a local and an external subscriber are connected in such a way that, ultimately, two local subscribers are connected to one another. The media proxy re-assigns the end points when making the connection, so enabling the direct transmission of the data streams between the local participants.