GL Announces Delay Emulation for Packet over SONET and ATM

A majority of the backbone transport for these applications continues to be SONET and SDH optical transmission. A dominant protocol for IP transport is PoS (Packet over SONET) and another is ATM (Asynchronous Transfer Mode). Both schemes are packet based, with ATM using fixed size packets of 53 bytes called cells, and PoS using variable packet sizes closely matching to Ethernet frames.

Both technologies can and often do coexist in a network. ATM switches often aggregate cell traffic in the access area (from DSL lines) and PoS is used more frequently in the core network for high speed transport, due to better efficiency. Core Routers, DSLAMs, Edge Routers, and User applications over such hybrid networks will benefit from lab testing and verification before deployment.”

He added, “GL's LightSpeed1000 hardware platform (PCIe Card) is capable of OC-3/12 and STM-1/4 Wire-Speed Processing on Dual Optical Ports for such functions as wire-speed recording and wire-speed playback. Normally, the LightSpeed1000™ is used for protocol analysis of ATM, PoS, Raw unchannelized and unframed data, and Ethernet traffic at IP, UDP, and higher layers. The hardware can be easily configured / programmed for delaying of ATM cells or PPP packets.”

Mr. Vadalia further added, “Packet Delay Network Emulator feature combines hardware and software based functions to achieve precision and flexibility. Delays are programmable from 1 ms to 500 ms with incremental delays of 1 ms. SONET/SDH overhead, scrambling, HDLC processing are terminated on the receive side and regenerated on the transmit side.

PPP frames are removed from the payload, time stamped and store and forwarded based on user delay settings. ATM cells are similarly store and forwarded. Flags and idle cells are inserted as appropriate in the output stream. The Packet Delay Network Emulator is transparent to higher layer protocols above ATM and PoS. A simple GUI allows user modification of delay and port settings.”