LAPD Configuration Sequence

The following is the configuration sequence to bring LAPD channels into service to communicate with the host.

2 Assign Logical Span IDs to the physical E1 spans
API message: Assign Logical Span IDs

5 Configure the Connection Endpoint type to be Euro-ISDN
API message: ISDN Interface Configure

6 Configure whether LAPD Entity is User or Network side
API message: ISDN Interface Configure

7 Configure the D channel Speed (default is 64 kbps)
API message: ISDN Interface Configure

8 Configure the LAPD options to enable host-to-Layer 2 messaging
API message: ISDN Terminal Configure

9 Configure the terminal types and TEI values
API message: ISDN Terminal Configure

10 Configure LAPD timers and counters (if it is necessary to change them)
API message: ISDN Terminal Configure

12 Send PPL Event Request to L2 to redirect Output to Local Host
API message: PPL Event Request (Layer 2)

14 Await Layer 2 up DL Establish. This and subsequent Establish Indications are reported to the Local Host.
API message: PPL Event Indication (Layer 2).

Link Access Protocol (Procedure) – D channel (ISDN)

Range of channels provided by T1 or E1 transmission service. A physical span is a group of channels taking up a single physical wire. A logical span is a group of channels taking up less than a single logical wire, or carried over more than one physical wire.

A digital communications link - voice, data, and video at a 2.048 Mbps rate; 30B/2D or 31B/1D (ISDN); non-North American version of T1.

Signaling technique where the full channel bandwidth is used for data transmission, while the framing and control bits (signaling) use a separate channel. No control or signaling is performed on this path. See B8ZS and ZBTSI.

See Integrated Services Digital Network.

Data channel. One of two fundamental components of an ISDN interface, it provides a path (16Kbps for BRI, 64Kbps for PRI) for carrying control signals and call data in a packet-switched mode.

An H.323 terminal or gateway, or MCU. An endpoint can call and be called. It generates and/or terminates the information stream.

The condition of a component at a given instant. The current "context" of a PPL object, such as Idle, Seizing, Answered. In PPL files, a State is represented by a circle.

See Programmable Protocol Language.

A computer, attached to the Excel platform through an RS-232 or Ethernet link, from which you run the telecommunications application that controls the Excel platform.

A condition that, when met, drives a state machine from one state to another. A condition that drives a Component out of its current state by invoking an associated primitive.