Clearspan® Product Overview R19
Aastra – 2740-007
2014 Clearspan® is a Registered Trademark of Aastra Technologies Ltd.
Page 33 of 93
2.4.2.2
Inbound Call Flows
The second case examines an inbound call which is a call received by a user serviced by the
Enterprise Clearspan node. The signaling and call flows are reversed from those followed for the
outbound calls described in the previous section.
The SIP Signaling request is received by the Clearspan node from the service provider
network (1) and (2).
Upon being processed by the Clearspan server complex, the signaling is forwarded over
the customers’ LAN to the SIP endpoint that is being called (3) and (4).
Upon the called SIP endpoint accepting the inbound call, the Clearspan node will send the
appropriate signaling acknowledgments and responses back through the service provider
network to the calling party to complete the call setup.
Upon completing the call setup, the RTP media stream is routed directly between the
remote party (via the service provider network) and the user
’s SIP terminal. The only
Clearspan server that the RTP would traverse after the call setup process is completed is
the SSM (5).
Figure 17. Clearspan Inbound Signaling and Call Flows.
