Cisco Cisco Expressway
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Unified CM dial plan
The Unified CM dial plan is not impacted by devices registering via Expressway. Remote and mobile devices
still register directly to Unified CM and their dial plan will be the same as when it is registered locally.
still register directly to Unified CM and their dial plan will be the same as when it is registered locally.
Expressway call types and licensing
The Expressway distinguishes between the following 2 types of call:
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Unified CM remote sessions: these are "mobile and remote access" calls i.e.video or audio calls from
devices located outside the enterprise that are routed via the Expressway firewall traversal solution to
endpoints registered to Unified CM. These calls do not require rich media session licenses, although they
do contribute to overall load.
devices located outside the enterprise that are routed via the Expressway firewall traversal solution to
endpoints registered to Unified CM. These calls do not require rich media session licenses, although they
do contribute to overall load.
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Rich media sessions: these calls consume rich media session licenses and consist of every other type
of video or audio call that is routed through the Expressway. This includes business-to-business calls,
B2BUA calls, and interworked or gatewayed calls to third-party solutions. The Expressway may take the
media (traversal) or just the signaling (non-traversal).
Audio-only SIP traversal calls are treated distinctly from video SIP traversal calls. Each rich media
session license allows either 1 video call or 2 audio-only SIP traversal calls. Hence, a 100 rich media
session license would allow, for example, 90 video and 20 SIP audio-only simultaneous calls. Any other
audio-only call (non-traversal, H.323 or interworked) will consume a rich media session license.
of video or audio call that is routed through the Expressway. This includes business-to-business calls,
B2BUA calls, and interworked or gatewayed calls to third-party solutions. The Expressway may take the
media (traversal) or just the signaling (non-traversal).
Audio-only SIP traversal calls are treated distinctly from video SIP traversal calls. Each rich media
session license allows either 1 video call or 2 audio-only SIP traversal calls. Hence, a 100 rich media
session license would allow, for example, 90 video and 20 SIP audio-only simultaneous calls. Any other
audio-only call (non-traversal, H.323 or interworked) will consume a rich media session license.
Both types of call contribute to the overall load on the system.
Note that:
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Expressway defines an "audio-only" SIP call as one that was negotiated with a single “m=” line in the SDP.
Thus, for example, if a person makes a “telephone” call but the SIP UA includes an additional m= line in the
SDP, the call will consume a video call license.
Thus, for example, if a person makes a “telephone” call but the SIP UA includes an additional m= line in the
SDP, the call will consume a video call license.
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While an "audio-only" SIP call is being established, it is treated (licensed) as a video call. It only becomes
licensed as "audio-only" when the call setup has completed. This means that if your system approaches its
maximum licensed limit, you may be unable to connect some "audio-only" calls if they are made
simultaneously.
licensed as "audio-only" when the call setup has completed. This means that if your system approaches its
maximum licensed limit, you may be unable to connect some "audio-only" calls if they are made
simultaneously.
Deploying Unified CM and Expressway in different domains
Unified CM nodes and Expressway peers can be located in different domains. For example, your Unified CM
nodes may be in the enterprise.com domain and your Expressway system may be in the edge.com
domain.
nodes may be in the enterprise.com domain and your Expressway system may be in the edge.com
domain.
In this case, Unified CM nodes must use IP addresses or FQDNs for the Server host name / IP address to
ensure that Expressway can route traffic to the relevant Unified CM nodes.
ensure that Expressway can route traffic to the relevant Unified CM nodes.
Unified CM servers and IM&P servers must share the same domain.
Unified Communications Mobile and Remote Access via Cisco Expressway Deployment Guide (X8.5.2)
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Additional information