Lucent Technologies 7820-0802-003 Taos unit terminating voice and data calls in an SS7 network

Signaling System 7 (SS7)

System requirements for SS7 operations

TAOS unit as terminator of voice and data calls in an SS7 network

With the IPDC license, the TAOS unit can communicate with the signaling gateway by means of IPDC. IPDC enables the TAOS unit to terminate voice or data calls. An example of TAOS units being used both for Internet call diversion (data) and Voice over IP (VoIP) is shown in Figure 18-2.

Figure 18-2. TAOS unit terminating voice and data calls in an SS7 network

Data and voice path without IPDC
Egress CO	Tandem CO	Ingress CO
switch	switch	switch
PRI
ISP A				PSTN
	SS7 Network
A-links		IMT data
ISP B
		trunk
Signaling
gateway		IPDC
ISP C		TCP/IP	TAOS	MultiVoice
	Frame Relay,
				gateway 1
Data path with IPDC	ATM, or IP
		Voice path with IPDC

IMT trunk

PSTN

TAOS

MultiVoice gateway 2

SS7

Signaling gateway

Connection to the SS7 network is achieved through a signaling gateway. This gateway provides a bridge to the SS7 network and performs service switching point functions such as initiating and managing call setup and release, and executing call routing. IPDC must be supported by both the signaling gateway and the TAOS unit.

The signaling gateway uses the IPDC protocol to convert the SS7 signaling information and call data from the PSTN into IPDC packets, which are sent to the TAOS unit. In addition, the gateway uses IPDC to convert IPDC packets received from a TAOS unit into SS7 format before sending the call to the PSTN.

Before sending call data across the IP network, the TAOS unit uses IPDC to extract TDM and IP routing instructions from the IPDC packets received from the signaling gateway. The far-end TAOS unit then forwards IPDC packets to a signaling gateway, which converts them back into SS7 messages before the call is connected.

APX 8000/MAX TNT/DSLTNT Physical Interface Configuration Guide 18-3