Cisco Cisco Expressway
Voice and Video Calling
SIP Calls
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SIP endpoints registered to Unified CM can make calls to Lync clients registered to Lync Server.
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Lync clients registered to Lync Server can make calls to SIP endpoints registered to Unified CM.
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SIP signaling and RTP media is always routed via the B2BUA application for calls involving Lync clients. Each
B2BUA application (one application per Expressway) can handle 100 simultaneous calls between Lync and
the Expressway video environment.
B2BUA application (one application per Expressway) can handle 100 simultaneous calls between Lync and
the Expressway video environment.
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Media encryption (SRTP) is supported when TLS is used between Expressway and Lync and the Microsoft
Interoperability option key is added to the Gateway Expressway.
Interoperability option key is added to the Gateway Expressway.
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Lync Server accepts and handles call hold (and resume) requests.
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Lync clients can be the object of a transfer (even if there is an AM gateway involved in the call).
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The maximum resolution of an SVC to AVC converted call is 720p 30fps.
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Lync client sometimes notifies that it has no audio device configured when selecting resume. Follow Lync
client’s instructions to update the audio device to get hold/resume working.
client’s instructions to update the audio device to get hold/resume working.
Upspeeding a Voice Call to Video
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If a voice call is made from a Lync client to a UCM-registered endpoint, and then the video button is selected
to enhance the call to a video call, the video endpoint will correctly upspeed to video.
to enhance the call to a video call, the video endpoint will correctly upspeed to video.
MXP Endpoints
Video from MXP endpoints to Lync 2013 H.264 SVC is limited to 15fps (video with other endpoints is 30fps).
Screen Sharing
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Lync clients can share their screen with standards-based endpoints in the video network, because the
Gateway Expressway can transcode RDP media into H.264.
Gateway Expressway can transcode RDP media into H.264.
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The reverse transcode (from H.264 to RDP) is not supported. If the endpoint is capable of putting the
presentation in the main video channel, then the Lync user can see the presentation that way. Otherwise, if
the parties are in a conference, the conference bridge will compose the presentation (from the standards-
based endpoint) into the main video it sends to the Lync user.
presentation in the main video channel, then the Lync user can see the presentation that way. Otherwise, if
the parties are in a conference, the conference bridge will compose the presentation (from the standards-
based endpoint) into the main video it sends to the Lync user.
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Lync Server 2013 is the required server version for screen sharing. Other server versions are not supported for
this feature.
this feature.
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The following Microsoft clients can share their screen through the Gateway Expressway, when they are in a
Lync Server 2013 environment:
Lync Server 2013 environment:
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Lync 2013 for Windows (desktop version)
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Skype for Business 2015 (desktop version)
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Skype for Business 2016 (desktop version)
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Mobile versions of Lync and Skype for Business cannot share their screens.
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Screen sharing from Lync is supported when the Lync client is in a conference on a Cisco TelePresence
Server, with the following caveat:
Server, with the following caveat:
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In a conference hosted by a Conductor-managed TelePresence Server, a Lync client cannot share its
screen if the conference has dialed out to the Lync client. The Lync client can share its screen if it has
dialed in to the conference.
screen if the conference has dialed out to the Lync client. The Lync client can share its screen if it has
dialed in to the conference.
7
Cisco Expressway with Microsoft Lync Deployment Guide
Introduction