From the Security Experts

January 20, 2012

GL Rolls-Out New SA Bit HDLC Protocol Analysis and Playback Software

By SIP Trunking Report Contributor

GL Communications Inc., a provider of test, monitoring, and analysis equipment for TDM, Wireless, IP and VoIP networks, has rolled-out a new SA Bit High-Level Data Link Control (HDLC) Protocol Analysis and Playback software, which provides the capability to capture, and analyze HDLC data on a full duplex T1 or E1 line.

For those unaware, HDLC is a bit-oriented, switched and non-switched data link layer protocol developed by International Organization for Standardization (ISO). This protocol can embed information in a data frame allowing data flow control and error correction.

The HDLC has been widely used to connect one device to another. It is being deployed because it supports both half duplex and full duplex communication lines, point to point (peer to peer) and multi-point networks, and switched or non-switched channels.

According to the source, Timeslot0 of every basic frame is reserved for basic frame alignment and contains either a Frame Alignment Signal (FAS) or a Non-Frame Alignment Signal (NFAS), wherein FAS and NFAS occur in timeslot0 of consecutive basic frames. Bits four to eight of the NFAS (i.e., Sa4 - Sa8) are additional spare bits generally called as Signaling Associated (Sa) bits.

The HDLC frames can be transmitted on timeslot0 Sa bits (bits 4-8 of the non-frame alignment signal) and can operate at 4,8,12,16 or 20 kbit/s depending on which Sa bit is selected, according to the source.

Vijay Kulkarni CEO of GL Communications, said in a press release, "GL's Sa Bits HDLC Analyzer performs Sa Bits HDLC protocol analysis on E1 timeslot 0 during real-time and off-line. Users can capture stream of Sa Bit HDLC frames on the selected even or odd frames of the E1 multiframe on timeslot 0.”

Kulkarni added, “Captured information can be saved to disk for later off-line analysis. Both real-time and off-line analysis presents summary and detailed views of Sa Bit HDLC decode information. Captured frames can later be used for traffic simulation using the Sa Bits HDLC transmit application."

Apart from having remote monitoring capability using GL's Network Surveillance System, the new Sa Bits HDLC Analyzer supports decoding of LAPD, LAPF, LAPD+IP, LAPX+IP protocols; and provides Summary, Detail, Hex dump and Statistics Views.

The Summary View on the new Sa Bits HDLC Analyzer displays selected frames, sub channel, frame#, device#, time relative, length, and more. The Detail View displays decodes of user-selected frames from the Summary View. The Hex dump View displays raw frame data as hexadecimal and ASCII octet dump. The Statistics View displays statistics based on frame count, byte count, frames/sec, bytes/sec etc for the entire captured data.

Apart from supporting filtering and search features based on C/R, SAPI, TEI, CTL, P/F, N(S), N(R) and FUNC, the new offering also features a status bar that display information regarding running percent utilization, number of frames captured, CRC errors and frame errors.

In addition, the Sa Bits HDLC Analyzer has the capability to export detail decodes information to an ASCII file

In recent news, as reported by TMCnet, GL Communications also rolled-out a new Automated Acoustic Echo Cancellation (AEC) Compliance Test Software, which features rich application that allows users to perform acoustic echo cancellation testing in accordance with ITU-T Specifications, G.167 (03/1993) and P.340 (05/2000) and a TDM Protocol Identifier Software designed to identify various protocols carried on T1 or E1 lines.

Want to learn more about the latest in communications and technology? Then be sure to attend ITEXPO East 2012, taking place Jan. 31-Feb. 3 2012, in Miami, FL. ITEXPO offers an educational program to help corporate decision makers select the right IP-based voice, video, fax and unified communications solutions to improve their operations. It's also where service providers learn how to profitably roll out the services their subscribers are clamoring for – and where resellers can learn about new growth opportunities. For more information on registering for ITEXPO registration click here.

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Jayashree Adkoli is a contributing editor for TMCnet. To read more of Jayashree's articles, please visit her columnist page.

Edited by Rich Steeves