SONET & SDH optical testing

OC-3/STM-1 and OC-12/STM-4 Analysis and Emulation

OC-3 / STM-1 and OC-12 / STM-4 Analyzer
for ATM Mode - LightSpeed1000™ (Legacy)


Asynchronous Transfer Mode (ATM) is a flexible network protocol carrying voice, video, and data in fixed length cells. ATM network has two kinds of interfaces, UNI (Interface between ATM User and Public ATM switch) and NNI (Interface between two Public ATM switches). Similar to the OSI Protocol model, ATM has an ATM Layer as Layer 2, ATM Adaptation Layer (AAL) as Layer 3 and other higher layers depending on C-Plane, U-Plane or Layer Management Plane.

GL's LightSpeed1000™ analyzer supports ATM interfaces on both ports and can be configured for either OC-3 or OC-12 rate. Multiple cards can be installed in a PC making it scalable to monitor or generate OC-3 or OC-12 traffic on multiple boards. Each port on a card can work independent of others, which extends analyzer's flexibility as test equipment.

The LightSpeed1000™ complies with ITU-T ATM standards. The ATM layer architecture and ATM cell structure in UNI and NNI formats are shown below:

ATM layer architecture

ATM layer architecture

ATM cell structure in UNI and NNI formats

ATM cell structure in UNI and NNI formats


  • Supports signal rates of 155.52 Mbps for OC-3 and 622.08 Mbps for OC-12 interface.
  • Emulation and analysis modes are supported on UNI or NNI per port.
  • Wire speed cell generation and processing on single or multiple ports using internal logic.
  • Capture to file on individual ports, limited only by hard disk size.
  • Simultaneous synchronous capture or transmit is possible on both optical ports
  • Comprehensive transmit/receive testing capabilities; transmitting and verifying with incrementing sequence numbers with each packet/cell.
  • ATM Tx/Rx application - Supports ATM traffic generation and cell analysis.
  • Ability to configure ATM headers (GFC, VPI, VCI, PT, and CLP fields), and bandwidth during traffic generation.
  • Rx cell analysis reports resync count errors and sequence errors.
  • Multistage loopback - Supports Rx-to-Tx memory loopback, line loopback, diagnostic loopback and PL3 loopback options.
  • Ability to capture real-time traffic and playback the traffic for simulation.
  • Complex and flexible hardware based filtering includes sixteen 128 bit independent filters with bit masks, for both ports with AND/OR include/exclude conditions
  • ATM and UMTS protocol analysis supported on single or multiple ports
  • Supports both AAL2 and AAL5 decoding.
  • Bit Error Rate Test module supports generation and analysis of payloads at wire speed. Supports ATM header configuration, PRBS patterns and user-defined patterns as payload. Report on error count, error rate, sync loss, SES, and others is provided.
  • Received cells hardware time stamping to the accuracy of 10ns.
  • SONET level statistics for both Tx and Rx cells. Additional statistics for errors, alarms, and BERT test cells.
  • Monitor and configure section, line, and path overhead bytes.

Basic Applications

Alarms and Error Counters Monitoring

The alarms and error monitoring window provided for each of the OC-3/OC-12 port displays detailed status of the communication with the other end. Hardware LEDs are provided on the card to read line alarms.

Alarms and error counts include -

  • Line errors such as OOF, LOS, LOF, AIS, RDI, and APSBF
  • Line, Path, and Section error counts
Alarm Monitor

Alarm Monitor

Rx-To-Tx Memory Loopback

Software memory loopback is used for diagnostic purposes. It loops all the received packets / cells from the SONET to the transmitting ports. This module uses both ports on the selected board.

Features include

  • selection of source and destination ports to transmit and receive packets/cells,
  • selection of ports on different boards for Tx and Rx, where multiple boards are used in a single chassis,
  • display of Tx and Rx information
  • loop back the data either in the page mode, 4K bytes at a time, or in the packet mode, packet by packet
Memory Loopback

Memory Loopback

Memory Loopback

ATM Configuration allows user to either pass or drop idle cells at the receiving stream.

ATM Configuration

ATM Configuration

Optional Applications

Following are the other applications supported in LightSpeed1000™ ATM analyzer. Note that these applications require additional licenses. Visit the links below to get more information -


Item No Item Description
LTS200 OC-3 / STM-1 ATM Monitor, BERT, Tx/Rx Test
LTS300 OC-12 / STM-4 ATM Monitor, BERT, Tx/Rx Test
LTS202 OC-3 / STM-1 ATM and RAW Record / Playback
LTS302 OC-12 / STM-4 ATM and RAW Record / Playback
LTS204 OC-3 / STM-1 ATM Protocol Analysis
LTS304 OC-12 / STM-4 ATM Protocol Analysis
  Other Related Software
LTS201 OC-3 / STM-1 PoS Monitor, BERT, Tx/Rx Test, RAW
LTS301 OC-12 / STM-4 PoS Monitor, BERT, Tx/Rx Test, RAW
LTS203 OC-3 / STM-1 PoS and RAW Record / Playback
LTS303 OC-12 / STM-4 PoS and RAW Record / Playback
LTS205 OC-3 / STM-1 PoS Protocol Analysis
LTS305 OC-12 / STM-4 PoS Protocol Analysis
LTS206 OC-3 / STM-1 UMTS Protocol Analysis
LTS306 OC-12 / STM-4 UMTS Protocol Analysis
  Related Hardware
LTS100 Lightspeed1000™ - Dual OC-3/12 STM-1/4 PCIe Card
LTS105 Lightspeed1000™ - Portable Dual OC-3/12 STM-1/4 USB Unit
SFP, Single Mode
SFP, Multimode


1 Gbps / 10 Gbps Fiber Optic Cable, Single-Mode, Duplex LC to Duplex LC
1 Gbps / 10 Gbps Fiber Optic Cable, Single-Mode, Duplex LC to Duplex SC
1 Gbps / 10 Gbps Fiber Optic Cable, Multi-Mode, Duplex LC to Duplex LC
1 Gbps / 10 Gbps Fiber Optic Cable, Multi-Mode, Duplex LC to Duplex SC
40G / 100G  Fiber Optic Cable, Multi-Mode  
40G / 100G  Fiber Optic Cable, Single-Mode