Cisco Cisco Expressway
Client support
Expressway is generally compatible with Lync 2010 and Lync 2013 clients, including mobile clients. When
specific issues are discovered, they are recorded on the
specific issues are discovered, they are recorded on the
Interoperability with different versions of Lync Server
The known differences in interoperability when Expressway integrates with Microsoft Lync Server 2013 or
Lync Server 2010 are summarized below:
Lync Server 2010 are summarized below:
Microsoft Lync Server 2010
The Microsoft Interoperability option key must be installed to enable encrypted calls to and from Microsoft
Lync 2010 Server (for both native SIP calls and calls interworked from H.323). It is also required by the
B2BUA when establishing ICE calls to Lync 2010 clients.
Lync 2010 Server (for both native SIP calls and calls interworked from H.323). It is also required by the
B2BUA when establishing ICE calls to Lync 2010 clients.
The B2BUA can use the Cisco AM GW to transcode between standard codecs (such as H.264) and
Microsoft RT Video and RT Audio to allow high definition calls between Microsoft Lync 2010 clients and
Cisco endpoints.
Microsoft RT Video and RT Audio to allow high definition calls between Microsoft Lync 2010 clients and
Cisco endpoints.
Microsoft Lync Server 2013
The B2BUA provides interworking between standard H.264 AVC and Lync 2013's H.264UC SVC codec.
You can still configure the B2BUA to use Cisco AM GW transcoders with Lync 2013, but it is not necessary
and we recommend that they are not deployed with Lync 2013.
You can still configure the B2BUA to use Cisco AM GW transcoders with Lync 2013, but it is not necessary
and we recommend that they are not deployed with Lync 2013.
Lync 2013 no longer supports H.263, so X8.1 or later software is required to interoperate successfully with
Lync 2013.
Lync 2013.
The Microsoft Interoperability option key is required for all types of communication with Lync 2013.
Microsoft Lync B2BUA interoperating capabilities
When using the Microsoft Lync B2BUA:
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Domain static routes are set up on Lync Server to route calls to domains in the video network.
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Search rules are set up on Expressway to route calls to Lync domains.
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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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Calls to Microsoft Mediation Servers work from endpoints in the Expressway video network for SIP
initiated calls, but do not work for calls interworked from H.323 (unless the workaround specified in
initiated calls, but do not work for calls interworked from H.323 (unless the workaround specified in
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Lync systems may use hardware load balancers for resilience and capacity.
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A “Lync gateway” Expressway (or Expressway cluster) can communicate to Lync via Lync Director.
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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 “Lync gateway” Expressway.
Microsoft Interoperability option key is added to the “Lync gateway” Expressway.
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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. However, a call involving Cisco AM GW will consume two
B2BUA call resources.
Each B2BUA application (one application per Expressway) can handle 100 simultaneous calls between
Lync and the Expressway video environment. However, a call involving Cisco AM GW will consume two
B2BUA call resources.
Microsoft Lync and Cisco Expressway Deployment Guide (X8.5)
Page 9 of 71
Introduction