The following procedure is for measuring Ethernet Service Disruption Time (SDT) with the MPA
The MPA unit can measure Service Disruption switching intervals in your network to determine how long it takes for your network equipment to react to a service disruption event and switch to a backup path.
When enabled, the trigger event to begin service disruption measurements occurs on incoming packets with FCS/CRC errors, or when it stops detecting incoming packets (Frame Loss).
The duration for every Ethernet service disruption event is measured in milliseconds, with granular accuracy of 0.1 ms (100 µs).
When the Action State is configured for Continuous Measurement, the 10 most recent measurements are displayed in the Last 10 Events history section. Also, the Current (ms), Average (ms), Minimum (ms), and Maximum (ms) measurement times are displayed in the Event Summary section, based on all measurements taken since the test began.
To measure Ethernet Service Disruption activity:
- Using the WebUI login, select the test port's Ethernet - Tests tab, and choose Service Disruption from the tabs along the left-side of the screen and configure the following settings.
- Consecutive Good Time Required: Select Consecutive Good Time Required and enter a time interval ranging from 10 milliseconds to 1,638.3 milliseconds.
- This function allows you to enter the time-duration (in milliseconds) of consecutive error-free frames to elapse before Protection Switch measurements stop accumulating.
- Consecutive Bad Time Required: Select Consecutive Bad Time Required and enter a time interval ranging from 0.1 milliseconds to 1638.3 milliseconds.
- This function allows you to enter the time-duration (in milliseconds) of consecutive errored frames (or frame loss) to elapse before Protection Switch measurements begin to accumulate.
- Resolution: If testing low-speed Ethernet bandwidths (≤ 2.5Gbps), you may also need to configure the Resolution setting.
- This function is only visible when testing Ethernet rates of 2.5G and below, and is needed to ensure that at least one Ethernet packet is received within the configured period of time (measurement window).
- The following options are available:
High (0.1 ms)- Medium (1 ms)
- Low (10 ms)
When receiving fewer packets per second (lower bandwidths), a lower resolution setting is required (larger window of time).
Invert the number of packets per second being received to determine the time between each received packet, and select the Resolution setting that best allows for at least one packet to be received within the selected measurement window.
- Action: Select Single Measurement or Continuous Measurement to begin measuring Service Disruption. The unit begins monitoring the incoming signal for a Service Disruption measurement events as soon as one of the following Actions are selected:
- Single Measurement: Monitors for a single trigger event to occur, and automatically turns the Action to “Off” after the event is recorded.
- The Measurement Status will show “Measuring” when the event is actively occurring, and returns to “Inactive” after the measurement stops.
- Continuous Measurement: Constantly monitors for trigger events, and updates the list of measured events reported.
- The Measurement Status will show “Measuring” when an event is actively occurring and “Waiting for trigger” between measurements.
- Each measurement will include the duration (in milliseconds) of each switch event, including the preceding “Bad” time required to trigger the measurement.
- Off: Stops Service Disruption monitoring. The Measurement Status returns to Inactive.
- Event Summary Table: Indicates the Current (most recent), Average, Minimum, and Maximum durations (in milliseconds) that it took for the service disruption events (errored frames) to occur.
- Last 10 Events Table: A history view of the 10 most recent measurements are displayed (in milliseconds).