GL offers delay emulation for packet over SONET and ATM

Network monitoring and test and measurement specialist GL Communications has introduced a Packet Delay Network Emulator application for its LightSpeed1000 Packet over SONET (PoS) and ATM tester. Through a combination of hardware and software, the LightSpeed1000 can now provide full-duplex delay emulation for PoS and ATM based traffic from 1 ms to 500 ms. The unit supports OC-3/12 and STM-1/4 data rates.

The LightSpeed1000 hardware platform (PCIe card) supports 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. Users can now configure/program the unit to delay ATM cells or PPP packets. In this mode, the user can:

• test the impact of delay and congestion under various real world conditions
• assess impact of delay on service-level agreements (SLAs)
• simulate satellite delay and long fiber loops
• test WAN application performance under deteriorated but repeatable conditions.

Packet/cell out of sequence, duplication, errors, and drop are features that will be added in future releases, the company says.

SONET/SDH overhead, scrambling, and HDLC processing are terminated on the receive side and regenerated on the transmit side. PPP frames are removed from the payload, time stamped, and stored and forwarded based on user delay settings. ATM cells are similarly stored 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, GL Communications adds. A GUI allows user modification of delay and port settings.

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