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MAPS™ ISDN SIGTRAN Protocol Emulator
(SIGTRAN ISDN over IP Emulation)

MAPS™ ISDN SIGTRAN Protocol Emulator Software Ver 5.7.24 | Download Now!


ISDN is a very common protocol in the legacy network. There are two types - PRI (Primary Rate Interface or 23B +D) for T1 E1 lines and BRI (Basic Rate Interface, or 2B + D) for lower speed digital lines. As PSTN networks migrate to Next Generation Networks (NGNs), a need for conversion and transport of signaling and media (voice) is necessary. NGNs are IP based systems, therefore protocols have been developed to reliably transport/adapt Q.920s (data link layer) and Q.930s (Layer 3 user messages) TDM protocols.

This adaptation is performed by two IP based protocols within SIGTRAN, called SCTP and IUA. SIGTRAN, shortened form of Signaling Transmission, is the standard for conversion, transport, and encapsulation of SS7 and ISDN over IP. It is one of the most important transition elements in moving from legacy TDM to NGN IP networks.

As shown above, a Signaling Gateway (SG) on the TDM side connects to standard PRI T1 E1 lines (or BRI) and translates the ISDN messages to SIGTRAN IP format. It supports the same application and call management functions as ISDN but uses two protocol layers on top of Internet Protocol (IP): Stream Control Transport Protocol (SCTP) and ISDN Q.921-User Adaptation Layer (IUA). The SG talks to a Media Gateway Controller, which in turn performs further routing and signaling decisions within the NGN. The protocol architecture of ISDN SIGTRAN is shown below.

ISDN end-points in Next Generation Network


Message Automation & Protocol Simulation (MAPS™) is a powerful protocol test simulation platform supporting a wide range protocols such as SIGTRAN (SS7 over IP), SS7 over TDM (T1 E1), ISDN over TDM (T1 E1), GSM-A & GSM-Abis over TDM, Megaco, SIP, and MGCP over IP.

GL’s MAPS™ SIGTRAN ISDN over IP is an advanced protocol simulator/tester used for ISDN simulation over IP. The tester can simulate a complete ISDN connection SG to MGC, where ISDN signaling is defined by the ITU-T Q.921 / Q.931 standards. MAPS™ SIGTRAN ISDN over IP is a powerful tool that can be used to perform detailed testing of ISDN protocol messages over IP, and offers a complete solution for testing, troubleshooting, and maintenance of devices and networks implementing PRI ISDN and BRI ISDN.

MAPS™ SIGTRAN ISDN over IP can act as the SG when testing the MGC or as the MGC when testing the SG as shown below.

Location of MAPS™ SIGTRAN ISDN over IP Emulator in the Network

MAPS™ SIGTRAN ISDN over IP also incorporates the flexibility to modify ISDN call parameters & message contents (arbitrary manipulation of messages, information elements and message sequence on the different protocols). This flexibility ensures that the MAPS™ SIGTRAN ISDN over IP communicates with the system under test.

The application is available as -

  • MAPS™ ISDN SIGTRAN Emulator (Item # PKS135)
    MAPS™ ISDN SIGTRAN Emulator supports both PRI (Primary Rate Interface or 23B +D) and BRI (Basic Rate Interface, or 2B + D) ISDN network types. ISDN BRI is referred to as 2B + D, as it includes 2 bearer ‘B’ channels each with 64 kbit/s rate and one 16 kbit/s signaling channel ('D' channel or data channel). ISDN PRI when carried over an E1 includes 30 'B' channels and over T1 has 23 ‘B’ channels of 64 kbit/s, shared with 'D' channel of 64 kbit/s.

    MAPS™ ISDN SIGTRAN protocol test tool simulates complete ISDN connection from TDM to Signaling Gateway (SG) and Media Gateway Controller (MGC) supporting both PRI ISDN (with traffic) and BRI ISDN interfaces.  MAPS™ ISDN SIGTRAN connects to traditional ISDN interfaces and IP-enabled signaling nodes and offloads TDM traffic to IP networks. The various supported TDM traffic types include File, Digits, Tones, FAX, IVR, Dynamic VF, and Voice Quality Testing. MAPS™ can be configured to auto start the traffic over ISDN signaling or manually define traffic at run time.

    MAPS™ SIGTRAN ISDN over IP  supports powerful utilities like Message Editor and Script Editor which allows creating new scenarios or modifying the existing scenarios using ISDN messages and parameters.

    Also available is an independent GUI based SIGTRAN (ISDN over IP) Protocol Analyzer for online capture and decode of the signaling in real-time both during tests and as a stand-alone tracer for live systems.

Main Features

  • Simulates ISDN signaling over IP (ISDN-SIGTRAN)
  • Generates and process all ISDN messages such as Setup, Connect, Release messages, and more
  • Switch and Subscriber Emulation
  • Supports interfacing with both high-speed PRI (Primary Rate Interface or 23B +D) and low-speed BRI (Basic Rate Interface, or 2B + D) digital lines.
  • User controlled access to optional ISDN parameters such as timers
  • Provides various release cause codes such as rejected, no user response, user busy, congested, and so on to troubleshoot the problems in ISDN
  • Impairments can be applied to messages to simulate error conditions
  • Supports TDM traffic (including digits, voice file, tones, IVR, FAX, Dynamic VF, IVR and Voice Quality Testing) over IP.
  • Supports Client-Server functionality requires additional license; clients supported are TCL, Python, VBScript, Java, and .Net
  • Automation, Remote access, and Schedulers to run tests 24/7

Supported Protocols Standards

ISDN Sigtran protocol stack

Supported Protocols Standard / Specification Used
Q.931 ITU-T Q.931 / Q.932(Facility IE) / Q.955.3 (MLPP Procedures)
IUA RFC 4233 Integrated Services Digital Network (ISDN) Q.921-User Adaptation Layer


Call Simulation over ISDN SIGTRAN

Given below is a typical ISDN call scenario that can be simulated using MAPS™ at either of the peer ends (Switch/ Subscriber):

The Sigtran call procedure is as shown below with two telecom switches exchanging the ISUP messages. Detailed call flows are provided in ITU-T Recommendation Q.784.1.

MAPS™ ISDN SIGTRAN application can be configured as SUBSCRIBER and SWITCH terminals to simulate ISDN signaling over IP and TDM traffic in PRI ISDN network.

Typical ISDN SIGTRAN Call Procedure

Test Setup Simulating TDM Traffic

TDM Traffic Simulation over ISDN SIGTRAN (Call Generation)

TDM Traffic Simulation over ISDN SIGTRAN (Call Reception)

General MAPS™ Features

Call Simulation and Control

The signaling and traffic simulation in a call is completely implemented using scripts. Commands in the scripts are executed in controlled way to simulate protocol and traffic behavior. Most of the commands used in the scripts are generic and independent of specific protocol.

MAPS™ application acts as either the Caller or resides at the network terminal acting as Callee. The Call Generation feature simulates an outgoing call by sending call control messages to the DUT using scripts and profiles. The profiles allow necessary parameters of call control messages to be changed during runtime. Call generated from other entity can be automatically detected in call reception window by pre-setting the required answer scripts in the Incoming Call Handler.

The call control scripts can also automatically handle the traffic over the established call. MAPS™ supports transmission and detection of various traffic types over  IP (RTP, GTP), ATM, & TDM - such as, digits, voice file, single tone, dual tones, fax, sms, email, http, ftp, and video. MAPS™ also includes support for wide range of codec rates – visit and webpage for more details.

Message Sequence - Each call scenario provides the trace with full decoding of the messages exchanged between the MAPS™ and the DUT, and graphical ladder diagrams of the call flow with time stamp. Impairments can be applied to messages to simulate error conditions that occur in real-time networks.

Event-Driven Control - Scripts execution, being event-based, allows redirection of script execution on-the-go with user-defined events. The custom parameters in the events can also be changed during script execution using event profiles.

Script Contents & Script Flow - The script flow and the contents window displays the Script Name, Sub-script Name, Script line number, and script statements to be successfully executed, which help the users in troubleshooting a particular call scenario.

Bulk Call Simulation and Load Testing

MAPS™ supports automated stress/load testing capabilities through Load Generation and Bulk Call Simulation features. Bulk Call Simulation allows quick configurations to easily create multiple test entries with different scripts and profiles. Multiple tests can be run simultaneously or sequentially (queue up tasks in succession). Load generation feature further allows specifying the patterns with which the bulk calls can be generated. Load generation can be customized with different statistical distribution patterns such as Uniform, Ramp, Sawtooth, Fixed, Normal, Step, and Step-Sawtooth distribution. Call duration also can be randomized using similar statistical distribution. This feature also helps users configure Stress/Load Testing parameters such as Call per second (CPS), Max Active Call, Minimum and Maximum Call Rates, Start Call Rates, and other parameters.


Scheduler can be used to schedule the simulation of bulk calls or manual calls at a specific start time. The pre-saved master configuration files for test setup and call simulation are automatically loaded to automate the test procedure.

Customization of Test Setup Parameters

The test setup profiles (.xml files) allow users to configure the necessary parameters in order to establish communication between MAPS™ and the DUT. It includes configuring parameters of the network nodes, the network properties, and transport related configurations such as T1/E1 timeslots, IP Address and port numbers for both MAPS™ and the DUT.

Once the transport layer is configured properly, protocol specific signaling messages and traffic can be transmitted and received successfully. All parameters setup in test setup are global and are accessible to all scripts. These parameters initialize protocol engines and the transport modules specific to the protocol.

Customization of Test Parameters, Call Flow, and Protocol Messages Using Pre-Processing Tools

  • Message Editor - The Message Templates (GL’s proprietary *.HDL files) comprises of protocol encoding parameters with preset values. It is required to create a message template for every message in a protocol. The message templates are called within the scripts to perform scenario based testing.
  • Profile Editor – Profiles (*.xml files) are used to change the values of the fields in the messages (i.e. Message Template in MAPS™) during the course of a call. The multiple profiles with varying parameter values that allow users to configure call instances in call generation and to receive calls.
  • Script Editor - The script editor allows the user to create / edit scripts and to define variables for the fields in the messages. The script uses pre-defined message templates to build call flow and perform send and receive actions. Script editor provides options to run the test for multiple iterations in sequential or random flow. Commands allow retransmission of messages with specific interval.

Command Line Interface

Supports scripting through a Command Line Interface (CLI) such as the Python, and TCL, using MAPS™ client-server functionality (requires additional license)

MAPS™ can be configured as server-side application, to enable remote controlling of the application through multiple command-line based clients. Supported clients include C++, TCL, Python and others. TCL provides a simple scripting language, with programming facilities such as looping, procedures, and variables. The TCL Client application includes a MapsTclIfc.dll file, a packaged library that enables communication with the Server from a TCL environment.

User can remotely perform all functions such as start test bed setup, load scripts and profiles, apply user events such as send digits/file/tones, detect digits/file/tones, dial, originate call, terminate call, start and stop traffic and so on. User can also generate and receive calls through commands. This client application is distributed along with MAPS™ Server application. Multiple MAPS™ CLI servers can be controlled remotely from single client application (such as TCL, Python, etc).

Call Statistics, Events, Link Status

Call Status & Message Statistics - By default, all call handling scripts (irrespective of the type of the functions) are assessed by MAPS™ to provide statistical information about Total Calls, Active Calls, Completed Calls, Passed Calls, Failed Calls, and Calls/Sec. It is also possible to categorize the statistical information as per the call handling scripts. In addition, Call Generation and Call Reception windows provide useful call status & script execution results.

In addition, Message Stats option for any specific protocol, logs number of times the messages are being transmitted (Tx Count) and received (Rx Count), thus allowing user to monitor the occurring events.

Events Reporting – MAPS™ provides Event Log, Error Events, and Captured Errors windows that log the captured events and errors encountered during the progress of the call.

Link Status - Link Status window indicates transport related information of the protocol, for example, if SCTP is used as transport, it indicates if the association is Up or Down in the Link Status window. MAPS™ IuCS ATM uses SSCOP transport and the associated link status is indicated as Up or Down in the Link Status window.

A Typical MAPS™ Sigtran Test System

A typical MAPS™ ISDN Sigtran consists of:

  • A TCL interface communicating over TCP/IP to a Rack PC with T1/E1 Analyzer Software
  • The Rack PC consists of MAPS™ Client IFC, MAPS™ CLI Server, T1/E1 Analyzer Software (including Windows Client Server software) and a Dual T1/E1 Card
  • A patch panel for RJ-11 connections to the outside world (DUT)
  • TCL Client – Acts as User Interface, which executes TCL Scripts.
  • MAPS TCL Interface (MAPS Client IFC) – acts as an interface between MAPS™ CLI Server and its client TCL. It interprets the TCL Commands and forms the appropriate command as understood by MAPS CLI Server and vice versa.
  • MAPS™ CLI Server is an executable that inherits all features of MAPS™ without GUI. It listens to a TCP message socket to receive and execute commands from client and sends the responses back to client.

T1/E1 Windows Client Server - Windows Client/Server software performs all ISDN emulation primitives including signaling, tone detection, call progress signals, file transfer, and many more functions.

TCL application consists of three functional modules: Tool Command Language (Tcl) Client and Script, MAPS™ Tcl Interface, and MAPS™ Server
In CLI, MAPS™ Server constitutes two server modules, namely MAPS™ CLI server and GL WCS server.

  • MAPS™ CLI Server
    MAPS™ CLI Server is an executable which inherits all features of MAPS™ without the graphical user interface. Instead it listens to TCP message socket to receive and execute commands from the client and sends the responses back to the client.
  • GL's Windows Client Server
    GL's Windows Client/Server software allows the user of T1/E1 analysis cards the capability of remote operation, automation, and multi-site connectivity.

TCL client receives report event from the CLI server as shown in the figure below.


TCL client placing the call



Screen Shot of PRI ISDN SIGTRAN Testbed Setup Configuration

Screen Shot of BRI ISDN SIGTRAN Testbed Setup Configuration

Screen Shot of Load Generation Parameters

Screenshot of Script Editor


Screenshot of Profile Editor

Screenshot of Message Editor

Screenshot of Call Statistics

Screenshot of Message Statistics


Screenshot of Event Log

Screenshot of Script Contents and Script Flow

Screenshot of Link Status


Buyer's Guide

Please Note: The XX in the Item No. refers to the hardware platform, listed at the bottom of the Buyer's Guide, which the software will be running on. Therefore, XX can either be ETA or EEA (Octal/Quad Boards), PTA or PEA (tProbe Units), UTA or UEA (USB Units), HUT or HUE (Universal Cards), and HDT or HDE (HD cards) depending upon the hardware.

Item No. Item Description
  MAPS™ SIGTRAN Conformance Test Suite (Additional License), requires PKS130
  Related Software
PKS164 MAPS™ UMTS IuPS interface
XX165 T1 or E1 UMTS Protocol Analyzer
OLV165 Offline UMTS Protocol Analyzer
LTS206 OC-3 / STM-1 UMTS Protocol Analysis
LTS306 OC-12 / STM-4 UMTS Protocol Analysis
PKS140 MAPS™ LTE S1 Emulator
PKS142 MAPS™ LTE eGTP Emulator




MAPS™ SIP Emulator

MAPS™ SIP Conformance Test Suite (Test Scripts)


MAPS™ MEGACO Conformance Test Suite (Test Scripts)

MAPS™ MGCP Emulator


RTP Soft Core for RTP Traffic Generation
PKS100 PacketGen™ with PacketScan™
PKV100 PacketScan™ (Online and Offline)
PKB100 RTP Toolbox™
PKS110 Packet H.323
  MAPS™ UMTS IuCS ATM with Lightspeed1000™ 
LTS100 Lightspeed1000™ - Dual OC3/12 STM1/4 PCIe Card
LTS105 Lightspeed1000™ - Portable Dual OC3/12 STM1/4 USB Unit
LTS220 MAPS UMTS IuCS ATM over OC-3 / STM-1, requires LTS214
LTS214 OC-3 / STM-1 SSCOP Server
LTS217 OC-3 / STM-1 AAL2 Traffic Core
LTS320 MAPS UMTS IuCS ATM over OC-12 / STM-4, requires LTS314
LTS314 OC-12 / STM-4 SSCOP Server
LTS317 OC-12 / STM-4 AAL2 Traffic Core


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