West Corporation

Posted on November 30, 2012 by West Corporation 



9-1-1 Call Taking and ESInets

Very often, when PSAPs are looking to migrate to a next generation 9-1-1 solution, they request on-premises 9-1-1 call handling systems. Typically, the preference to deploy the equipment on the premises is intended to accommodate a severe network outage, ensuring survivability of the 9-1-1 call-taking operations at the PSAP.

However, the PSAP will not be able to receive 9-1-1 calls during such a scenario if it experiences a severe network outage that knocks out both redundant paths to the IP network. The only possible path into the PSAP may be the plain old telephone system (POTS) lines that deliver 9-1-1 calls via seven or 10-digit lines. In the most severe network outages, POTS lines would also be affected, as they may be served via the same end office or central office that processes 9-1-1 calls and/or provides the last mile connectivity into the PSAP.

On-premises 9-1-1 call-processing equipment (CPE) does not provide any more survivability during this scenario once a PSAP has migrated to an IP-based call-handling infrastructure. As a matter of fact, PSAPs that migrate to an IP-based call routing solution or an emergency services IP network (ESInet), only gain greater survivability when the CPE is located in geographically diverse data centers accessed via a public-safety-grade IP network or cloud. Admin or POTS lines are terminated at the PSAP premises using “Admin Gateways” which terminate seven or 10-digit lines at the PSAP, allowing the PSAP to still process admin calls even if both IP paths are out of service.

With CPE in the cloud, PSAPs can ensure greater survivability as they easily move their operations to an alternate location and quickly connect to their data and configuration to answer 9-1-1 calls.  This model of adding call taking capability to the ESInet via a cloud-based solution provides PSAPs with the greatest level of operational continuity. In the event of a planned or unplanned outage, PSAPs can sustain 9-1-1 services by leveraging additional resources at various levels from neighboring jurisdictions.

By Ashish Patel, Systems Architect, Safety Services – West

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