# 5 Layer 4 Call Control

Overview

Layer 4 Call Control is a PPL-based programmable software environment that provides programmable services for implementing advanced call processing applications. It is the default central call processing software for the Converged Services Platform (CSP).

In this section:

Layer 4 Call Control Overview

Call Control Software Model

Call Control Software Interfaces

Call Control Internal Interfaces

Call Control Call Flows

Redundancy

Modifying a Connection Path Without Parking Channels

Call Control - Multi-Host Control

Call Control Connection Management

Connection Management Messages

Cross Connections

Calling Party Control of Disconnect

Modifying API Messages

Call Control - Tones Generation and Reception

Call Control - Release

Answer Supervision

Call Processing Guidelines

Call Control - Default Call Flows

Call processing layer of the CSP.
Setting up, monitoring, and tearing down calls.
See Programmable Protocol Language.
An Internet Protocol enhanced service node that supports the deployment of voice and data services in circuit, packet, and converged networks. The Converged Services Platform (CSP) features an open and multi-functional platform design that enables developers to quickly create and deliver new revenue-generating services for both legacy and next-generation networks.