Nortel Networks NN43001-314 - Manual (Page 316)

316 Emergency Services configuration
Either of these methods have a Branch Office implementation which triggers
the main office Call Server to forward emergency services calls to the MG
1000B PSTN. Calls are redirected over a Virtual Trunk using the services
of the NRS.
Emergency Services Access (ESA)
Routing ESA calls
ATTENTION
IMPORTANT!
Do not route ESA calls to a node that has no direct ESA trunks.
Ideally, route ESA calls directly over Central Office (CO) trunks to the Public
Safety Answering Point (PSAP). In those cases where this routing is not
possible, do not route ESA calls to nodes that have no direct ESA trunks.
The implications of routing calls to nodes without direct ESA trunks are as
follows:
• At the node without the direct ESA trunks, the node cannot route the
ESA call directly to the PSAP. Instead, that node must re-route the call
to another node. This re-routing is an unnecessary use of resources.
• If the node is a CS 1000E node, the only tandem trunks are IP Peer
trunks. There is no way to specify the appropriate rerouting digits (that
is, Prepend Digits) to reroute the ESA call to another node with direct
ESA trunks.
Therefore, if you are unable to route ESA calls directly to the PSAP, the next
best practice is to route ESA calls to nodes with direct ESA trunks.
Emergency call routing
A Call Server can provide service to IP phones across multiple emergency
jurisdictions. This can also occur with traditional non-IP equipment in the
form of remote peripheral equipment (for example, Carrier Remote, Fiber
Remote).
An emergency call should be handled by the designated means for the
phone location (for example, local security desk or local PSAP). The
emergency call should be routed to a service at the current location of the
phone.
PSTN routing: Enhanced 911 versus Basic 911
Currently, no industry-standard (wireline) solution exists for routing an
emergency call to an arbitrary PSAP, and delivering location data. With
Enhanced 911 (E911), multiple Emergency Service Zones (PSAP areas)
are connected by an E911 Tandem system. The PSTN first routes an
emergency call to the E911 Tandem, which contains a Selective Router.
Nortel Communication Server 1000
Branch Office Installation and Commissioning
NN43001-314 01.02 Standard
Release 5.0 20 June 2007
Copyright © 2007, Nortel Networks
.