Federation Call Flow Skype for Business and Lync clients


We always have requests from customers and other engineers to do articles containing edge and federated call flows. While working with another engineer internally (we will call him Jasco J) we started debating and came up with various answers. Since we couldn't agree on an answer we decided to ping some other Lync experts (JimmyV, Thomas Binder, TommyM). Below you will find the consensus of our discussion on how this actually works.

 

Peer to Peer Media Establishment (Federated):  CustomerA IS federated with CustomerB. CustomerA initiates a call to CustomerB.

What are the possible call flow paths?

Calling Party<->CalledParty – this would more than likely only be possible if the users from CustomerA and CustomerB were sitting on the same network.

Calling Party<->CallingPartyEdge<->CalledPartyEdge<->CalledParty – FTURN – this is the most common scenario that would work.

Calling Party<->CalledPartyEdge<->CalledParty – if 50K port range was opened for the Called party Edge.

Calling Party<->CallingPartyEdge<->CalledParty – if 50K port range was opened for the Calling party Edge.

 

Conferencing Media Establishment (Non-Federated):  CustomerA is NOT federated with CustomerB. CustomerB creates a Lync meeting and sends it to CustomerA. CustomerA joins the meeting.

  1. Customer A is joining using the Lync 2010 client – CustomerA (attendee) will connect to the AV Edge of CustomerB (organizer). So media will be from CustomerA to CustomerB either using the 50K port range or tunneled on UDP 3478 or TCP 443 just like a remote user connecting to the edge.
    1. Calling Party (attendee) <-> CalledPartyEdge (organizer) <-> AV MCU (organizer) – this would succeed if 50K port range was open.
    2. Calling Party (attendee) <-> CalledPartyEdge (organizer) <-> AV MCU (organizer) – tunneled via UDP 3478 or TCP 443
       
  2. Customer A is joining using the Lync 2013 client - CustomerA will try to tunnel media traffic to its own Edge which will then do FTURN with CustomerB's Edge. If the FTURN is successful, the media will be between CompanyA's Edge and CompanyB's Edge on 3478 -3478 for audio and 50k source to 443 destination for desktop sharing. If FTURN fails then media between the Edge servers will try to use 50k range ports.
    1. Calling Party (attendee) <-> CalledParty (AV MCU) - Unlikely, but possible. The non-Federated user would have to be internal to the network where the conference is hosted
    2. Calling Party (attendee) <-> CalledPartyEdge<->CalledParty (AV MCU) – would mean the AV MCU can directly connect to 50k of the attendee Edge
    3. Calling Party (attendee) <-> CallingPartyEdge<->CalledPartyEdge<-> AV MCU (organizer) - FTURN – this is the most common scenario that would work.

 

Conferencing Media Establishment (Federated):  CustomerA IS federated with CustomerB. CustomerB creates a Lync meeting and sends it to CustomerA. CustomerA joins the meeting.

  1. Customer A is joining using the Lync 2010 client – CustomerA (attendee) will connect to CustomerA's Edge then to CustomerB's (organizer) Edge and finally onto the MCU provisioned for the meeting from the organizer pool
    1. Calling Party (attendee) <-> CallingPartyEdge (attendee Edge) <-> CalledPartyEdge (organizer) <-> MCU (organizer)
  2. Customer A is joining using the Lync 2013 client - CustomerA will try to tunnel media traffic to its own Edge which will then do FTURN with CustomerB's Edge. If the FTURN is successful, the media will be between CompanyA's Edge and CompanyB's Edge on 3478 -3478 for audio and 50k source to 443 destination for desktop sharing. If FTURN fails then media between the Edge servers will try to use 50k range ports.
    1. Calling Party (attendee) <-> CalledParty (AV MCU) - Unlikely, but possible. The non-Federated user would have to be internal to the network where the conference is hosted
    2. Calling Party (attendee) <-> CallingPartyEdge<->CalledParty (AV MCU) - Very unlikely. Would mean the AV MCU can directly connect to 50k of the attendee Edge
    3. Calling Party (attendee) <-> CallingPartyEdge<->CalledPartyEdge<-> AV MCU (organizer) - FTURN – this is the most common scenario that would work.
    4. Calling Party (attendee) <->CalledPartyEdge<-> AV MCU (organizer) - If attendee can connect directly to 50k of the AV MCU Edge

 

 

References –

Thomas Binder Edge Session - https://aka.ms/AVEdge

Scott Stubberfield Anonymous Join Blog - http://blogs.technet.com/b/scottstu/archive/2015/04/03/anonymous-join-from-skype-for-business-and-lync-clients.aspx

 

Comments (3)

  1. linus says:

    Hi,
    Conferencing Media Establishment (Non-Federated)
    2.b is that should be Calling party Edge ? just like
    Conferencing Media Establishment (Federated) 2.b
    …Please ignore if i am wrong

  2. Alzoo says:

    Brilliant, thank you for this, just what I was looking for!!

  3. Hi, Interested in the scenario where OWA is involved!

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