Lucent Technologies Release 8.2 manual Call-signaling data, DCS-signaling data

DEFINITY Switch Connectivity 1 Networking Overview

What is transmitted between connected switches?

How does the data move between switches?

TCP/IP signaling connections were introduced with DEFINITY Release 7. Starting with R7, X.25 was no longer sold with new systems. R7 and later new systems ship with only TCP/IP connections or ISDN-PRI for DCS signaling. However, existing systems with X.25 and/or ISDN-PRI DCS signaling can be upgraded to the latest version and keep those signaling links, or a new system can be added to an existing DCS network. Connections to the CMS Call Center and Intuity AUDIX adjuncts can use either X.25 or 10Base-T DCS signaling.

When a DCS network uses a mixture of two or three of the different DCS signaling types, one or more switches in the network must act as a gateway. A gateway switch is connected between two switches using different signaling protocols and the gateway enables the two end switches to communicate by converting the signaling messages between the two protocols. A gateway switch can provide conversion between two or all three of the signaling protocols, but only one protocol can be used for DCS signaling between any two switches.

A telephone call consists of voice (bearer) data and call-signaling data. If the call is over a DCS network, DCS signaling data is also required. The DCS signaling data is sent over a separate path from the voice and call-signaling data.

Call-signaling data

The call-signaling data includes messages necessary to set up the call connection, maintain the connection during the call, and remove the connection when the call is finished.

DCS-signaling data

The DCS-signaling data is separate from the call-signaling data. How it gets transmitted depends on the connection type, which determines the type of signaling protocol used.

Figure 1 shows some of the major components of switch connections. Before R7, a call from switch 1 to switch 2, which consists of voice and signaling data, is sent through a trunk circuit pack across a TDM transmission facility to a trunk circuit pack in switch 2. Releases 7 and later add alternate pathways for the call data. In R8 and later releases, Q.931 signaling is used, which enables support for DCS+ and QSIG. The C-LAN circuit pack enables signaling data to be packetized and sent over a LAN, WAN, or the Internet. The IP Interface (TN802B) circuit pack enables voice data and non-DCS signaling data to be sent over IP facilities.

Administration for Network Connectivity
555-233-504 — Issue 1 — April 2000	CID: 77730	3