Overview
The Integrated Services Digital Network (ISDN) system allows voice, data and video to be transmitted simultaneously across the
world using end-to-end digital connectivity. ISDN, based on the telephony network, was conceived of to provide multiple voice and
non-voice services over a single network, and a digital user network interface over regular phone lines, instead of dedicated and
isolated user-network interfaces.
ISDN is an integrated solution for providing basic telephony and data services, whilst offering more telephony services such as
supplementary services.
ISDN services are grouped in three service categories:
- Bearer service
- Teleservice
- Supplementary service
The user-to-network interface is provided in two flavors:
- Basic interface structure (BRI) - two B-channels and one 16 kbit/s D-channel (2B+D)
- Primary rate B-channel interface structure (PRI) - 30 thirty B-channels and one 64 kbit/s D-channel (30B+D)
GL's ISDN analyzer can capture and analyze stream of frames on an ISDN PRI link. It decodes LAPD according to Q.921, while,
the ISDN information parsing is done based on the user's selection of ITU Q.931, AT&T/Lucent switch 4ESS and 5ESS (TR41449,
TR41459 and 235-900-342), Nortel's switch DMS-100 and DMS-250 (NIS-A2111-1 and NIS-A211-4), Bellcore National ISDN-2 (NI-2),
Euro ISDN (ETS-300 102-1), etc. GL Communications supports the following types of ISDN analyzers:
- Real-time ISDN Analyzer (Pre-requisites: GL's field proven E1 or T1 internal cards or USB Laptop E1 or T1 external units, required
licenses and Windows 2000/XP Operating System)
- Remote/Offline ISDN Analyzers (Pre-requisites: Hardware Dongle and Windows 2000/XP Operating System)
Both real-time and off-line analysis present the following information
- Raw ISDN Frame data as a hexadecimal and ASCII octet dump - Physical Layer
- LAPD information (Layer 2)
- ISDN information (Layer 3)
Also, visit GL's SIGTRAN protocol decode web page for a description of SIGTRAN - used to carry Q.931
or SS7 ISUP messages between IP nodes such as a Signaling Gateway and Media Gateway Controller or Media Gateway.
ISDN Analyzer Main Features:
- Displays Summary, detail, hex-dump, statistics, and call trace views.
- Summary view displays Dev #, Time Slot, Frame #, LAPD information, ISDN Message types etc.
- Detailed view displays decodes of user-selected frames.
- Hex dump view displays the frame information in HEX and ASCII format.
- Statistics view displays statistics based on frame count, byte count, frames/sec, bytes/sec etc for the entire capture data
- Call trace isolates call specific information i.e. status of each call (i.e. Active/Completed), duration of completed call, Device No,
Timeslot, CRV, Called and Calling Party number.
- Supports filtering and search features based on SAPI, TEI, C/R, N(S), N(R), P/F, Supervisory Functions, and ISDN message types.
- Exports detailed and summary information to a comma delimited file for subsequent import into a database or spreadsheet.
- Remote monitoring capability using GL's Network Surveillance System.
Additional feature supported by Real-time/Remote ISDN Analyzer:
- Real-time filter and search on C/R, SAPI, TEI, CTL, P/F, N (S), N (R) and FUNC and so on.
- Streams can be captured on the selected time slots (contiguous or non-contiguous), sub-channels or full bandwidth.
Frames can be transmitted/captured in either n x 64 kbps, or n x 56 kbps data channels (hyper-channels).
- Sub Channel and Nx56 hyper channel enables user to analyze data captured by fractional DS0 and DS1 link.
- Variations accommodated in the software include inverted or non-inverted data, and byte reversal or non-reversal
- Recorded trace files can be played back using HDLC playback option.
- Multiple remote clients may access a single T1/E1 server, which enables monitoring two or more cards instantaneously.
(For Remote Analyzers only)
- Multiple streams of ISDN traffic on various T1/E1 channels can be simultaneously decoded with different GUI instances
Additional features supported by Offline ISDN Analyzer:
- Trace files for analysis can be loaded through simple command-line arguments
- Multiple trace files can be loaded simultaneously with different GUI instances for offline analysis
Supported Protocols
Following is a description of the protocols supported by GL's ISDN analyzer:
- Layer 2: Conveys user information between Layer 3 entities across ISDN using the D-channel. LAPD is
parsed according to Q.921
- Layer 3: ISDN information parsing depends on the user's selection of the following ISDN Standards.
- Bell NI2 (Bellcore National ISDN-2): It is used in USA (Bellcore). It includes components to
communicate information between ISDN user equipment, and the ISDN switch.
- AT&T/Lucent switch 4ESS and 5ESS (TR41449, TR41459 and 235-900-342): It is an ISDN
variant adopted in USA by AT&T.
- ETSI 300-102 (Euro ISDN): This variant is adopted in all European countries.
- QSIG (Q-reference point Signaling System) ETSI: QSIG is inter-private PABX signaling system.
- Q.93x: It is an ITU implementation of ISDN
- Nortel's switch DMS-100/250(NIS-A2111-1 and NIS-A211-4): It is a Northern Telecom's
implementation of National ISDN
Summary, Detailed, and Hex-dump Views
The ISDN analyzer application is invoked from the main menu of GL's T1/E1 Analyzer for real-time analyzer. The remote/offline
ISDN analyzer is invoked from the installation directory of the remote ISDN Analyzer. The analyzer displays summary, detail and hex
dump view in different panes. The summary pane displays Direction, Frame Number, Time, Length, Error, Type of Frame, N (S), N(R),
Type of ISDN Messages, and more. User can select a frame in summary view to analyze and decode each frame in the detail view.
The selected frame is analyzed and decoded according to user selected ISDN specifications (switch). The Hex dump view displays
the frame information in HEX and ASCII formats.
Screen Shot of Summary and Detailed View
Real-time/Remote and Offline Analysis
Users can capture and analyze D-Channel using real-time or remote analyzers and record all or filtered traffic into a trace file.
The recorded trace file can then be analyzed offline and exported to ASCII file, or printed. Real-time capturing requires user to specify
timeslots, bit inversion, octet bit reversion, user/network side, and data transmission rate. Recorded trace file can be transmitted
back on T1/E1 using the HDLC File Playback option.
Screen Shot of Timeslot Selection
Filtering and Search
Users can record all or filtered traffic into a trace file. Filtering and search capability adds as another powerful feature to the
ISDN Analyzer. This feature can isolate required frames from captured frames in real-time as well as off-line. Users can specify
custom values for frame length to filter frames during real-time capture. The frames can also be filtered after completion of capture
according to SAPI, TEI, C/R, N (S), N(R), P/F, Supervisory Function and Type of ISDN Message. Similarly, search capability helps user
to search for a particular frame based on specific search criteria.
Screen Shot of Filtering and Search
Call Trace and Statistics View
Statistics and Call trace are important features available in ISDN analyzer and can be obtained for all frames both in real-time
as well as offline mode. Call trace defining important call specific parameters like. status of each call (i.e. active/completed),
duration of completed call, called and calling party number, call reference value (CRV) etc., for each individual call from the captured
data are displayed Call Detail Recording feature includes data link groups that help in defining the direction of the calls in a given
network and form logical groups comprised of unidirectional (either 'Forward' or 'Backward') data links.
Numerous statistics can be obtained to study the performance and trend in the ISDN network and it is based on protocol
fields and different parameters e.g. Use Type (Key/Total/Field), Statistic type (Frame count, Byte count, Frames/Sec) and patterns
like Range List, Wild card etc.
Screen Shot of Statistics and Call Trace
Enhanced Trace Saving Options
Users can control the captured trace files by saving the trace using different conventions such as trace files with user-defined
prefixes, trace file with date-time prefixes, and slider control to indicate the total number of files, file size, frame count, or time limit.
This feature also allows the captured frames to be saved into a trace file based on the filtering criteria set using display filter feature.
Screen Shot of Enhanced Trace Saving Options Window
Save/Load All Configuration Settings
Protocol Configuration window provides a consolidated interface for all the important settings required in the analyzer.
This includes various options such as protocol selection, startup options, stream/interface selection, filter/search criteria and so on.
All the configuration settings done in any of these options can be saved to a file, loaded from a configuration file, or user may just
revert to the default values using the default option.
Screen Shot of Save/Load All Configuration Setting Window
Sample Screenshots
Bridge and Monitor Connections
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 DPT, DPE, PCT, PCE, HDT, HDE, DLT, DLE or UTE depending upon
the hardware.
Specifications are subject to change without notice.
Back to Protocol Analysis Index Page
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![Exporting to ASCII File and Trace Savings Capability](javascript:myOpen("images/isdnscreen2.gif")){kind=link}
![Real-Time and Off-Line Search Capability](javascript:myOpen("images/isdnscreen6.gif")){kind=link}
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![Bridge Mode Connections for Monitoring T1/E1 Signals for RJ-45](javascript:myOpen("images/faq_figure4.gif")){kind=link}
![Bridge Mode Connections Alternative Method](javascript:myOpen("images/faq_figure5.gif")){kind=link}
![RJ-45 Connections](javascript:myOpen("images/faq_figure7.gif")){kind=link}
