MAPS™ ISDN SIGTRAN Protocol Emulator
(Scripted SIGTRAN ISDN over IP Emulation)
Background
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.
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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 – not shown) 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
Overview
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.
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.
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.
GL also provides a GUI based SIGTRAN Analyzer (PKV105) for on-line capture and decode of the
signaling in real-time both during tests and as a stand-alone tracer for live systems.
Supported Protocol Standards
| Supported Protocols |
Standard / Specification Used |
| Q.931 |
ITU-T Q.931 / Q.932(Facility IE) / Q.955.3 (MLPP Procedures) |
| 4ESS |
ISDN PRI (TR-41449) |
| 5ESS |
ISDN PRI (Lucent Tech - 5ESS 2000) |
| BELL |
ISDN PRI (Bell Core SR-NWT-002343) |
| DMS-100 |
Nortel's Switch DMS 100 NIS-A2111-1 |
| DMS-250 |
Nortel's Switch DMS 250 NIS-A2111-4 |
| QSIG ECMA |
Standard ECMA-143 4th Edition - December 2001 |
| IUA |
RFC 4233 Integrated Services Digital Network (ISDN) Q.921-User Adaptation Layer |
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
- 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 customization of call flows and message templates using Script editor and Message editor.
- Ready-to-use scripts for quick testing
- Supports scripted call generation and automated call reception.
- Provides protocol trace with full message decoding, and graphical ladder diagrams of call flow with time stamp
- Script based & protocol independent software architecture.
- Provides call statistics and associated captured events and error events during call simulation.
Test Configuration
This window allows users to configure the necessary parameters to establish communication between MAPS™ and the DUT.
MAPS™ SIGTRAN ISDN over IP communicates with the system under test, which can be a SG (Signaling Gateway) or MGC (Media Gateway Controller).
IUA protocol in SIGTRAN stack enables ISDN protocol to run over IP instead of TDM lines. The configuration window for MAPS™ SIGTRAN ISDN over IP
consists of SCTP Configuration and IUA Configuration settings.
Screen Shot of SIGTRAN ISDN over IP Testbed Setup Configuration
Call Generation
Call Generation option allows the user to simulate outgoing communications where an outgoing call is initiated by sending call control messages using
proper scripts and profiles. The profile allows necessary parameters of call control messages to be changed during runtime.
Call Flow diagram
Messages are exchanged between the MAPS™ and the DUT. MAPS™ application acts as either the Caller or resides at the network terminal
acting as Callee.
When MAPS™ SIGTRAN ISDN over IP is considered as Caller, it initiates the call flow by sending SETUP message to the DUT.
The screenshot below shows MAPS™ acting as subscriber and initiating the SETUP message to switch.
Call Generation
Call Reception
Call generated from other entity can be automatically detected in call reception window by pre-setting the required scripts in the Incoming Call
Handler window.
When MAPS™ SIGTRAN ISDN over IP is configured as receiving terminal; it processes the call flow by replying-back to the SETUP message
from the Caller.
The screenshot below shows MAPS™ acting as switch and responding to the SETUP message from subscriber
Screenshot of Call Reception Window
Bulk Call Simulation
MAPS™ ISDN SIGTRAN supports Bulk Call Simulation and Stress/Load Testing capabilities through Load Generation feature. Load Generation window helps
users configure Stress/Load Testing parameters such as Call per second (CPS) or Busy hour call attempts (BHCA), Max Simultaneous Calls and
Burst parameters.
Screen Shot of Load Generation Parameters
Customization of Call Flow and Messages Using Pre-Processing Tools
- Script Editor - The script editor allows the user to create / edit scripts and to define variables for the protocol fields. 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
Screenshot of Script Editor
- Profile Editor - Profiles are used to provide the user configured values to the fields in the Messages (i.e. Message Template in MAPS™)
through variables which are going to change during the course of a call.
Screenshot of Profile Editor
- Message Editor - The Message Template is a *.HDL file that 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.
Screenshot of Message Editor
Call Flow & Script Execution Control
Message Sequence - MAPS™ provides protocol trace with full message decoding, custom trace, and graphical ladder diagrams of call flow
with time stamp while simulation is running. Call flow graph allows to easily verify the messages exchanged between MAPS™ and DUT.
See Call Generation and Call Reception for details
Script Contents & Script Flow - The Scripts Contents window displays the contents of the script selected for call generation or reception. The
Script Flow window displays the set of statements successfully executed by MAPS™ to help users in troubleshooting a particular the call scenario.
Events & Event Profile Editor - User-defined events allow redirection of script execution on-the-go. The custom parameters in the events can
also be changed during script execution using Event Profiles.
Screenshot of Script Contents and Script Flow
Screenshot of Event Config
Call Statistics, Events, Link Status
Call Statistics & Status - 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, and failed calls. It is also possible to characterize the statistical information
under different groups of call handling scripts under a unique heading. In addition, Call Generation and Call Reception windows provide useful call
status & script execution results.
Screenshot of Call Statistics and Status
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.
Screenshot of Event Log
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.
Screenshot of Link Status
Buyer's Guide:
(XX can either be HDT, HDE, HUT, HUE, UTA or UEA depending upon the T1/E1 hardware)
Specifications are subject to change without notice.
Back to Message Automation & Protocol Simulation
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