GR-303 is a standard interface for Integrated Digital Loop Carrier (IDLC) systems that consists of an Integrated Digital Terminal (IDT) located in the Local Digital Switch (LDS) and a Remote Digital Terminal (RDT) located at the customer premises. RDT's main function is to multiplex traffic from a number of subscriber lines onto a high-speed transmission facility (SONET, DS3, or DS1s) for transport to/from the central office.
GR-303 uses three message-based signaling channels namely, Timeslot Management Channels (TMC), Common Signaling Channels(CSC), and Embedded Operation Channels (EOC). TMCs are used for timeslot allocation and call processing messages between the RDT and the LDS.
The higher layer protocols used with this channel are LAPD subset for layer 2, and a subset of Q.931 for layer 3. CSCs are used instead of TMC for clean out-of-band signaling implementation. CSC messages can handle both call supervision and time slot assignment. EOCs are used for remote management operations such as maintenance and alarm surveillance.
GL's GR303 Analyzer offers testing for all aspects of GR-303 systems: monitoring T1 Line, monitoring the TMC/CSC control channel, monitoring EOC channel, viewing robbed ABCD signaling and dialed digits, listening to voice channels, and thorough tests for the physical layer.
The GR-303 option troubleshoots signaling problems between the switch and remote terminal: to determine call status, monitor for any dropped calls, detect any abnormal conditions, and identify when service was unavailable. With these extensive GR-303 protocol analysis tools, you can analyze call setup and monitor communications between network elements and resolve problems as new network challenges emerge.
GL Communications supports the following types of GR-303 analyzers:
GR-303 Analyzer Main Features:
- Real-time GR-303 Analyzer (Pre-requisites: GL's field proven E1 or T1 internal cards or USB Laptop E1 or T1 external units, required licenses and Windows XP (or higher) Operating System)
- Remote/Offline GR-303 Analyzers (Pre-requisites: Hardware Dongle, and Windows XP (or higher) Operating System)
Additional features supported by real-time/remote GR-303 analyzer are:
- Decode Embedded Operational Channel (EOC) messages for diagnosing operations, administration, maintenance and provisioning (OAM & P).
- Provide real-time call-setup analysis of the Timeslot Management Channel (TMC) and Common Signaling Channel (CSC).
- Monitor both TMC/CSC and EOC simultaneously to correlate call-setup and OAM & P.
- Displays Summary, Detail, Hex-dump, Statistics, and Call Trace Views, the contents of this view can also be copied to clipboard.
- Summary View displays the SAPI, TEI, C/R, Message type (for TMC/CSC) and ROSE APDU (for EOC).
- Detail View displays decodes of user-selected frames from the Summary View.
- Hex dump View displays raw frame data as hexadecimal and ASCII octet dump the contents of this view can also be copied to clipboard.
- Statistics View displays statistics based on frame count, byte count, frames/sec, bytes/sec etc for the entire captured data.
- Call Detail View displays call statistics such as number of active/completed calls, durations of the completed calls, Device No, CRV and Timeslot.
- 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.
- Capability to export Summary View details to a comma separated values (CSV) format for subsequent import into a database or spreadsheet.
- Capability to export detail decode information to an ASCII file.
- Supports filtering and search based on Call Reference Value (CRV) and many other message types.
- Any protocol field can be added to the summary view, filtering, and search features providing users more flexibility to monitor required protocol fields.
- Remote monitoring capability using GL's Network Surveillance System.
Additional features supported by Offline GR-303 Analyzer:
- Streams can be captured on the selected time slots (contiguous or non-contiguous), sub-channels or full bandwidth. Frames may also be contained in either one, n x 64 kbps, or n x 56 kbps data channels.
- The following variations are accommodated in the software: inverted or non-inverted data, byte reversal or non-reversal.
- Supports decoding of frames with FCS of 16 bits and 32 bits, or none
- Supports real-time filtering based on the frame length value.
- Multiple streams of GR303 traffic on various T1/E1 channels can be simultaneously decoded with different GUI instances
- Multiple remote clients may access a single T1/E1 server, Also, the T1/E1 server is fully functional while being accessed as a server. Thus, a user may perform T1/E1 operations locally on the server while a remote client is accessing the same server, in real time, (For Remote Analyzers only)
- Captured frames can later be used for traffic simulation using HDLC Transmit/Playback application
- 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