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 OC3 or OC12 rate. Multiple cards can be installed in a PC making it scalable to monitor or generate OC3 or OC12 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 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.