Clearspan® Product Overview R19
Aastra – 2740-007
2014 Clearspan® is a Registered Trademark of Aastra Technologies Ltd.
Page 36 of 93
1. After dialing and pressing dial (or waiting for the digit timeout), the initial SIP signaling is
sent to the Clearspan node’s SIP Session Manager (SSM) server, which serves the SBC
functionality.
2. The SSM forwards the request (from a trusted source), to the Application Server (AS) to
perform the call setup.
3. Unlike either the Inbound or Outbound calls, the AS does not need to query the NS to
obtain the required routing and translating functions required to direct the call setup
request. The AS simply forwards the signaling request back to the SSM for forwarding.
The AS also initiates a CDR for record-keeping/accounting purposes.
4. The SSM directs the signaling request to the other internal SIP endpoint to complete the
call setup request.
2.4.3
911 and E911 Considerations
Clearspan provides a level of support for 911 and Enhanced 911 (E911) emergency dialing and
routing services by default. This basic level of support can be further extended through the addition
of optional third party products and services to provide a more robust solution with enhanced
notification capabilities for administrators.
The Clearspan platform can support multiple emergency call number sequences, and complete the
call appropriately for these different numbers. Clearspan can replace the dialed sequence of digits
defined for emergency purposes (for example, 911) with a fully specified directory number when
call originators may be in an area that does not support enhanced emergency call routing.
Figure 20. Internal Call setup Call Flows.
