Setting Up Delay Measurements

DMM measurements (delay and delay variation) work as follows. A DMM frame is sent from an originating unit to one of the remote devices linked to the Cisco Provider Connectivity Assurance Sensor Control. When the DMM frame is received by the remote device, it sends a DMR to the originating unit.

DMM measurements are measurements of network delay and network delay variation. The remote device needs to eliminate processing time in order to obtain a true measurement of the network delay and delay variation. This is accomplished by the use of four timestamps:

• a = Time that the DMM frame is transmitted by the originating unit
• b = Time that the DMM frame is received by the remote unit
• c = Time that the DMR frame (DMM response) is transmitted by the remote unit
• d = Time that the DMR frame is received by the originating unit

Using these timestamps, the originating unit calculates one-way and two-way delay as follows:

• One-Way Network Delay = d – c
• Two-Way Network Delay = d – a – (c – b)

▶ To configure a delay measurement reflection end point

1. Access the page SOAM ▶ CFM ▶ DMM ▶ Configuration.
   A listing of all existing Delay Measurement instances (reflectors) is displayed.

2. (Optional) To limit the view to only certain reflection end points, enter a value on which to filter, then click Search. You can filter by index value, DMM name, MEP idx, MEPID, RMEPID, Priority, Interval, or whether or not the end point has been enabled.

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   Note: Enter an asterisk ( * ) as a wildcard to replace one or several characters.

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3. In the Index column of the table, click the value associated with the end point for which you want to view detailed information.

For more information on specific parameters, refer to the following table.

DMM Configuration (SOAM ▶ CFM ▶ DMM ▶ Configuration)

▶ To configure DMM instances

1. Access the page SOAM ▶ CFM ▶ DMM ▶ Configuration.
   All existing Delay Measurement Instances are displayed.

2. Click Add to create a DMM instance or click the DMM instance index to edit an existing DMM instance.

3. Complete the required fields, then click Apply.

For more information on specific parameters, refer to the following tables.

DMM Configuration (SOAM ▶ CFM ▶ DMM ▶ Configuration)

One-Way Delay

One-Way Delay Variation

Two-Way Delay

Two-Way Delay Variation

▶ To delete a delay measurement instance

1. Access the page SOAM ▶ CFM ▶ DMM ▶ Configuration.

2. Click the index of the DMM instance to delete.

3. Click Delete.