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Newsletter: GL Enhances T1 E1 Applications with Bulk Delay and Error Insertion

Welcome to another June 2011 issue of GL Communications' Newsletter providing information and insight into our Enhanced Bulk Delay and Error Insertion Application.


Simulating bulk delay and errors like that found in real networks can help optimize the performance of applications. For example:

  • At what delay does the application under test suffer throughput degradation due to ARQ – Automatic Repeat Requests
  • At what error rates does voice performance on compressed codec circuits start to degrade.
  • How good is error correction when the underlying uncorrected error rate is 10E-5
  • How can I simulate the error characteristics of a microwave circuit, a copper T1 line, a fiber optic transmission line
  • Does encryption multiply the inherent error rate of the circuit and by how much?

Bulk Delay and Error Insertion

The Bulk Delay and Error Insertion application permits inserting single, fixed, automatic, random, and burst errors into the incoming bit stream. This application also includes a Bulk Delay feature that allows delay to be applied to the entire T1 E1 trunk of 1.544Mbps (T1) pipe or 2.048 Mbps (E1) pipe. Delays and errors can be different for different directions. A block diagram, GUI, and schematic of the function is provided above and below.

When the above feature is used in conjunction with “Cross Port Transmit”, introducing delays and errors is extremely easy.

In this Mode, the data that would normally be transmitted on Card 1 (Port 1) is diverted and transmitted on Card 2 (Port 2) and the data that would normally be transmitted on Card 2 (Port 2) is diverted and transmitted on Card 1 (Port 1). The receive paths are completely unaffected. This feature also eliminates complex cabling.

Other Features Include

  • Automated Random Errors can be inserted at a rate ranging from:
    • BPVs 10E-4 to 10E-9
    • Logic Errors 10E-2 to 10E-9
    • Frame Errors 10E-2 to 10E-9
    • CRC Errors 10E-2 to 10E-9
    • FDL Errors 10E-2 to 10E-9
  • Delay can be varied from 0 to 169.77mS (T1) or 127.99mS (E1) with an accuracy of ± 10uS
  • The bulk delay range can be extended further by other software based applications such as the Delay / Attenuate application

For comprehensive information on the application, please refere to the Bulk Delay and Error Insertion webpage.

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