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PPL Guidelines

This section gives general guidelines to follow when developing protocols. For more detailed information on using PPL for specific protocols, consult the API Reference and developer’s guides.

Idle State

The Idle state must be consistent with the default protocol for a component. A protocol must transition to the primary protocol without having any knowledge of the primary protocol's state/event and primitive table data.

T1 and E1

Since the E1 OOS protocol has no knowledge of the primary T1 and E1 protocol, the transmit IDLE line signaling ABCD bit values must be configured by sending a PPL Transmit Signal Configure message. This should be done prior to bringing the channel In Service. The Out of Service line signaling value is transmitted when a channel is being controlled by the OOS protocol (channel ID out of service).

Internal States

A given Internal State (test state) must accept all possible Internal PPL Events (test results) from a test AF that is invoked. The description of all test Atomic Functions indicate the possible Internal PPL Events that may be returned.

Multi-Purpose PPL Timers

Each component has 3 multi-purpose timers available for use within a protocol. These timers can be activated through an "Enable Timer" AF passing the timer number (1-3) in Arg1 and the preconfigured PPL timer setting ID (1-100) in Arg2. See the Overview section for more details on PPL Timers.

The preconfigured timer settings can be changed by the host using the PPL Timer Configure message. As timer adjustments are independent from the protocol tables you can modify a timer value without having to create new protocol tables.

When a timer expires, an event is generated into the PPL state machine for the associated channel. The timer events are numbers 191, 192, and 193.

Multiple Resident Protocols

The CSP allows for up to 10 custom protocols per component to be resident in the system at one time. Custom protocols can be given Protocol IDs from 1 to 10. Dialogic default protocols begin at Protocol ID 11.

Call Processing

The CSP software architecture shown in the figure below is similar to the OSI Layered Model. Inter-Layer communications between Layer 3 and Layer 4 must take place for call management. Specific events and AFs are provided for each PPL component to manage call processing. This section describes the required Layer 3 to Layer 4 messaging for incoming and outgoing calls.

Figure 1-5 CSP 2000 Software Architecture

Incoming Call

Condition | L3 to L4 Message
--- | ---
Incoming Call Setup Completed | L3 Þ L4 Setup Indication by L3
Terminating Party being Alerted | L4 Þ L3 Alerting
Terminating Party Answered | L4 Þ L3 Connect

Outgoing Call

Condition | L3 to L4 Message
--- | ---
Initiation of Outgoing Call | L4 Þ L3 Call Request or L4 Þ L3 Outseize Control
Outseizure Acknowledgment Successfully Detected by L3 | L3 Þ L4 Alerting
Answer Detected by L3 | L3 Þ L4 Connect

Network-initiated Call Release

Condition | L3 to L4 Message
--- | ---
Network Release Detected | L3 Þ L4 Disconnect by L3
L4 Acknowledgment of L3 Disconnect Request | L4 Þ L3 Clear
L3 Network Release Completed (L3 in Idle state) | L3 Þ L4 Clear

Host/Associated Party-initiated Call Release

Condition | L3 to L4 Message
--- | ---
L4-initiated Release | L4 Þ L3 Clear
L3 Network Release Completed (L3 in Idle state) | L3 Þ L4 Clear

See Programmable Protocol Language.
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.
In PPL, a condition that, when met, drives a state machine (PPL Component) from one state to another, by invoking an associated Primitive. In PPL files, an Event is marked by an arrow and text.
Digital communications link - voice, data, and video at a 1.544 Mbps rate (24 64 Kbps channels)
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.
Out of Service
See Atomic Function.
Open System Interconnection model
Protocol layer of the CSP.
Call processing layer of the CSP.
Outgoing call setup during real-time call processing on a specific channel.
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.