Nortel 1000S Overview page 28

Page 28 of 44 System architecture
553-3031-010 Standard 3.00
Terminal Proxy Server
The Terminal Proxy Server (TPS) acts as a signaling gateway between the IP
Phones and the Call Server using the UNIStim protocol. It performs the
following functions:
• converts the IP Phone UNIStim messages into messages the Call Server
can interpret
• allows IP Phones to access telephony features provided by the Call
Server
The TPS also controls the IP Phone registration.
SIP/H.323 Signaling Gateways
SIP/H.323 Signaling Gateways are software components configured on
virtual loops, similar to IP Phones. SIP/H.323 Signaling Gateways bridge
existing call processing features and the IP network. They also enable access
to the routing and features in the MCDN feature set.
Note 1: The SIP/H.323 Signaling Gateway must register with the
Network Routing Service (NRS).
Note 2: Virtual TNs enable you to configure service data without
hardwiring IP Phones to the CS 1000S system. Virtual TNs are
configured in LD 97.
To support IP Peer Networking, dual Call Servers in a CS 1000S must be
associated with Signaling Servers that run SIP/H.323 Signaling Gateway
software. The number of Signaling Servers required depends on the capacity
and level of redundancy required.
Network Routing Service
The NRS application provides network-based routing, combining the
following into a single application:
• H.323 Gatekeeper — The H.323 Gatekeeper provides central dialing
plan management and routing for H.323-based endpoints and gateways.
• SIP Redirect Server — The SIP Redirect Server provides central
dialing plan management and routing for SIP-based endpoints and
gateways.
August 2005