Cisco Cisco Expressway
sending all traffic to one Expressway unless it loses connection to that Expressway, and only then does it
swap to another Expressway – so this provides resilience rather than load balancing.
swap to another Expressway – so this provides resilience rather than load balancing.
Why add a “Lync gateway” Expressway?
The “Lync gateway” Expressway is an interface between an existing working video network and the
Microsoft Lync environment. Using this gateway minimizes the changes that need to be made in the video
network so as to introduce as few artifacts as possible when adding Lync interoperability to the video
network.
Microsoft Lync environment. Using this gateway minimizes the changes that need to be made in the video
network so as to introduce as few artifacts as possible when adding Lync interoperability to the video
network.
Having dedicated Expressways for this “Lync gateway” operation limits the number of Expressways for
which the Microsoft Interoperability option key needs to be purchased and enabled.
which the Microsoft Interoperability option key needs to be purchased and enabled.
Lync Server can only send calls to a single FQDN (though this may have a round robin DNS address to
support a cluster of Expressways for resilience) for calls via a static domain route defined in Lync Server.
support a cluster of Expressways for resilience) for calls via a static domain route defined in Lync Server.
Lync Server will only accept messages received from peers that it has been configured to trust. Having a
dedicated “Lync gateway” Expressway or Expressway cluster also limits the number of trusted devices that
need to be configured in Lync, as every device that sends SIP messages to Lync Server needs to be
explicitly listed as a trusted host in Lync Server.
dedicated “Lync gateway” Expressway or Expressway cluster also limits the number of trusted devices that
need to be configured in Lync, as every device that sends SIP messages to Lync Server needs to be
explicitly listed as a trusted host in Lync Server.
Multiple “Lync gateway” Expressways per Lync domain
Apart from when the Expressways are in a single “Lync gateway” cluster, this is not a recommended
architecture as calls from one video endpoint to another video endpoint that is called via its Lync domain will
get routed via Lync rather than directly through the video infrastructure; this will cause users to lose video
functionality such as duo video and far end camera control, and also possibly lose encryption and video
quality.
architecture as calls from one video endpoint to another video endpoint that is called via its Lync domain will
get routed via Lync rather than directly through the video infrastructure; this will cause users to lose video
functionality such as duo video and far end camera control, and also possibly lose encryption and video
quality.
Features and capabilities
The interoperating capabilities of Expressway and Microsoft Lync 2010 are broadly the same as between
Expressway and Lync 2013 except where specified in this document. X8.1 or later is compatible with both
Lync 2010 and Lync 2013 clients registered to either Lync 2010 or Lync 2013 front end servers. The main
differences in features and capabilities are summarized below.
Expressway and Lync 2013 except where specified in this document. X8.1 or later is compatible with both
Lync 2010 and Lync 2013 clients registered to either Lync 2010 or Lync 2013 front end servers. The main
differences in features and capabilities are summarized below.
Microsoft Lync 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 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 and Cisco Expressway Deployment Guide (X8.1)
Page 7 of 63
Introduction