AV-Edge Tunnel Mode RRS feed

  • Question

  • Hello together,

    i have very specific question for a skype for business environment: Under which circumstances  does the edge server establish the Tunnel Mode between two sides? (Slide 32: http://video.ch9.ms/sessions/lync/2014/NETW401_Nyce.pptx) 

    Will the Edge Server establish the Tunnel mode if the clients are connected to the front end server and so also connected to the internal edge interfaces? Will the edge server establish the tunnelmode when the clients are connected only over edge external interfaces?

    Thank you for your help.

    Best regards, Viktor.

    • Edited by viktoriously Tuesday, October 25, 2016 2:13 PM grammar correct
    Tuesday, October 25, 2016 2:12 PM


  • Tunnel mode will be only between two edge servers, it doesn't care if users is internal or external. The Edge server sends a special packet to UDP port 3478 on the other Edge to find out if it is OCS 2007 R2 or above. If it is then tunnel mode can be used, and all UDP traffic can be sent on these ports. Candidate data still includes the 50k ports, but the Edge server just contacts the other Edge server to share this information and connect.

    for reference https://ucgeek.co/2014/02/understanding-how-lync-establishes/

    • Proposed as answer by GUIz49 Tuesday, October 25, 2016 7:48 PM
    • Marked as answer by jim-xu Monday, November 7, 2016 1:52 AM
    Tuesday, October 25, 2016 4:22 PM