Measurement of network protection switch time

Abstract

This invention precisely and automatically measures the protection switch time of modern communication networks such as the SONET or SDH standard. An automated precision measurement device is provided which uses digital error detection and gated counter techniques to accurately measure the time required for a network element to switch from a defective line to a protected line for the purpose of delivering error free service to customer premises. The device accepts a line side signal, demultiplexes a payload test pattern from the standard mapping, and analyzes the payload pattern for errors. If errors are present, the device further measures the time that the errors persist (e.g., the time between the first error present to the last error present, inclusive). If the measurement was made during a protection switch event in the network element, then this time represents an accurate measurement of the protection switch time that affected the service. Alternatively, the device will measure the signal with embedded test pattern as demultiplexed from the terminal itself yielding a measurement from a customer interface point.