Clearspan® Product Overview R19
Aastra – 2740-007
2014 Clearspan® is a Registered Trademark of Aastra Technologies Ltd.
Page 38 of 93
Figure 21. Basic Clearspan E911 Call Flow for Normal Operation.
1. A 911 call is detected by the premises SBC and is configured to pass the call directly to
the hosted service call control. The ELIN/ANI is modified per the user’s account or group
configuration.
2. The call is routed to the premises and out of a local media gateway to the PSAP. Note the
gateway has the ability to overwrite the ELIN/ANI also.
3. Calls with the updated ELIN/ANI can also be sent directly to a VPC or SIP Trunk provider
and subsequently to PSAP.
2.4.3.1.2
Advanced 911/E911 Services (with optional EGW) Service Limitations
In addition to the basic default capabilities inherent to the Clearspan platform, customers can also
deploy Clearspan with an optional Emergency Gateway (EGW) to offer a more robust, survivable
solution. There are some constraints when deploying Clearspan with a redundant pair of EGW
premises-based appliances:
Media gateways are required in each applicable PSAP region for survivability.
Provides support for emergency calls from Share Call Appearance lines.
Supports automatic location tracking for SIP phones moving within the enterprise network
when Layer-2 discovery is enabled.
An ELIN/ANI is presented based on the physical location of the endpoint.
Multiple callback options (911 caller, emergency desk, etc.).
Extended notification/alerting support.
As with the case for the basic deployment option, workers with soft clients or moving desk
phones will be able to dial 911 services; however, it is incumbent upon the customer to
ensure that users’ locations are correctly updated in the appropriate databases.
