Overview of Dialogic® NaturalAccess™ SIGTRAN Stack

The Dialogic® NaturalAccess™ SIGTRAN Stack consists of the following SS7 layers:

SS7 layer

Description

M3UA

MTP 3 user adaptation layer

An adaptation layer protocol that replaces the traditional SS7 MTP 3 layer in an IP network. It supports the transport of SS7 MTP 3 user signaling messages (such as ISUP and SCCP) over IP, using the services of SCTP. M3UA is used for communication between an application server process (ASP) and a signaling gateway process (SGP), or communication between two IP server processes (IPSPs). An ASP can serve as a media gateway controller (MGC) or IP-resident database.

The M3UA implementation includes a data service API and a management API (MAPI). Host applications can use the service functions to transfer data, control flow, and obtain API statistics. They can use the management functions to configure and control M3UA entities, and to obtain status and statistical information from the M3UA layer.

For more information, see M3UA layer.

SCTP

Stream control transmission protocol

A reliable transport protocol that replaces the traditional SS7 MTP 2 layer in an IP network. It transports M3UA and higher layer SS7 signaling messages over IP networks.

The SCTP implementation includes a management API (MAPI) that host applications can use to configure and control SCTP entities, and to obtain SCTP status and statistical information from the SCTP layer.

For more information, see SCTP layer.


Note: The remainder of this manual refers to the Dialogic® NaturalAccess™ implementation of the SIGTRAN Stack as SIGTRAN.

SIGTRAN architecture

The following illustration shows the SIGTRAN high-level architecture:

 

Two endpoints in a SIGTRAN network are connected through an SCTP association. The endpoints can be logically connected in the following ways:

The following illustration shows an association that connects an ASP to a SGP:

 

The following illustration shows an association that connects endpoints from two IPSPs:

 

Associations are initiated automatically by SIGTRAN when the Ethernet interface becomes active. Dialogic® NaturalAccess™ SIGTRAN currently supports ASP and IPSP functionality. It cannot be used as an SGP.

SIGTRAN components

SIGTRAN consists of the following components:

Component

Purpose

M3UA layer

Provide a seamless replacement for MTP 3 to upper layer protocols, routes outgoing and incoming messages to specified destinations or applications, and reroutes traffic in the case of failure or congestion.

SCTP layer

Provides reliable transport for signaling.

TX alarms manager

Collects unsolicited alarms (status changes) generated by the SS7 tasks and forwards them to the host for application-specific alarm processing.

Operating system-independent TX device driver

Provides low-level access to the TX board from the host computer.

M3UA configuration program

Reads the M3UA configuration file and loads the configuration to the M3UA layer at system startup. For information, see the  Dialogic® NaturalAccess™ Signaling Software Configuration Manual.

M3UA service API

Functions that get and send data, control data flow, and return API statistics. For information, see M3UA service function summary.

M3UA management API

Functions that initialize, set, and return configuration parameters for M3UA entities. These functions can also control M3UA entities and return status and statistical information for these entities. For information, see M3UA management function summary.

SCTP configuration program

Reads the SCTP configuration file and loads the configuration to the SCTP layer at system startup. For information, see the Dialogic® NaturalAccess™ Signaling Software Configuration Manual.

SCTP management API

Functions that initialize, set, and return configuration parameters for SCTP entities. These functions can also control SCTP entities and return status and statistical information for these entities. For information, see SCTP management function summary.

M3UA sample application

Sample application that uses the M3UA service API to send and receive data, provided in source and object code formats.

M3UA management utility (m3uamgr)

Utility that uses the M3UA management API, provided in source code and object code formats. For information, see m3uamgr overview.

SCTP management utility (sctpmgr)

Utility that uses the SCTP management API, provided in source code and object code formats. For information, see sctpmgr overview.

txalarm utility

Utility that captures alarms from the board and optionally writes them to a log file.

CPK/OS operating system

Proprietary operating system for the TX series boards. Includes utilities for troubleshooting and statistics gathering. For more information, see the TX Utilities Manual.