Setting Up Delay Measurements
  • 25 Sep 2024
  • 5 Minutes to read
  • Contributors
  • PDF

Setting Up Delay Measurements

  • PDF

Article summary

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.


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

  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)

ParameterDescription
IndexThe index of the delay measurement instance
Name

DMM Name

The name of the delay measurement instance.
EnableSelect this box to enable reflecting DMM frames on the remote device specified above

▶ 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)

ParameterDescription
IndexThe index of the delay measurement instance
DMM NameThe name of the delay measurement instance.
MEP Index

MEP idx

The index assigned to the Maintenance association End Point
MEPIDThe local Maintenance association End Point Identifier
Remote MEPID

R-MEPID

The remote Maintenance association End Point Identifier
PriorityPriority value used in VLAN tags, if present, in the transmitted frame.
EnableEnables sending DMM frames at the specified interval.
Sampling Interval

Interval

The time at which this delay measurement instance issues DMM frames. Expressed in milliseconds.
Reference PeriodReference period in minutes for the delay measurements.

One-Way Delay

ParameterDescription
EnableEnables one-way delay measurement for this DMM instance.
Maximum Allowed ValueMaximum one-way delay in the Reference Period. Expressed in milliseconds.

If a certain number (set by next field value) of consecutive measurements exceeds this value, an alarm is triggered.

Instantaneous ThresholdThe number of consecutive measurements exceeding the Maximum Allowed value that triggers a one-way delay alarm for this Reference Period.
Average ThresholdOne-way average delay threshold, expressed in milliseconds, that triggers the average one-way delay alarm for this Reference Period.

Note: The threshold is expressed in milliseconds, but with microsecond granularity. Consequently, values such as 1.001 milliseconds are acceptable.

One-Way Delay Variation

ParameterDescription
EnableSelect to enable One-way delay variation measurements for this DMM instance.
Maximum Allowed ValueMaximum one-way delay variation, expressed in milliseconds, to monitor in the Reference Period.

If a certain number (set by next field value) of consecutive measurements exceeds this value, an alarm is triggered.

Instantaneous ThresholdNumber of consecutive measurements exceeding the Maximum Allowed Value that triggers a one-way delay variation alarm for this Reference Period.
Average ThresholdOne-way average delay variation threshold, expressed in milliseconds, that triggers the average one-way delay variation alarm for this Reference Period.

Note: The threshold is expressed in milliseconds, but with microsecond granularity. Consequently, values such as 1.001 ms are acceptable.

Two-Way Delay

ParameterDescription
EnableEnables two-way delay measurement for this DMM instance.
Maximum Allowed ValueMaximum two-way delay in the Reference Period. Expressed in milliseconds.

If a certain number (set by next field value) of consecutive measurements exceeds this value, an alarm is triggered.

Instantaneous ThresholdThe number of consecutive measurements exceeding the Maximum Allowed value that triggers a two-way delay alarm for this Reference Period.
Average ThresholdTwo-way average delay threshold, expressed in milliseconds, that triggers the average two-way delay alarm for this Reference Period.

Note: The threshold is expressed in milliseconds, but with microsecond granularity. Consequently, values such as 1.001 milliseconds are acceptable.

Two-Way Delay Variation

ParameterDescription
EnableSelect to enable Two-way delay variation measurements for this DMM instance.
Maximum Allowed ValueMaximum two-way delay variation, expressed in milliseconds, to monitor in the Reference Period.

If a certain number (set by next field value) of consecutive measurements exceeds this value, an alarm is triggered.

Instantaneous ThresholdSpecify the number of consecutive measurements exceeding the Maximum Allowed Value that triggers a two-way delay variation alarm for this Reference Period.
Average ThresholdSpecify the two-way average delay variation threshold, expressed in milliseconds, that triggers the average two-way delay variation alarm for this Reference Period.

Note: The threshold is expressed in milliseconds, but with microsecond granularity. Consequently, values such as 1.001 ms are acceptable.

▶ 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.

© 2024 Cisco and/or its affiliates. All rights reserved.
 
For more information about trademarks, please visit: Cisco trademarks
For more information about legal terms, please visit: Cisco legal terms

For legal information about Accedian Skylight products, please visit: Accedian legal terms and tradmarks



Was this article helpful?

Changing your password will log you out immediately. Use the new password to log back in.
First name must have atleast 2 characters. Numbers and special characters are not allowed.
Last name must have atleast 1 characters. Numbers and special characters are not allowed.
Enter a valid email
Enter a valid password
Your profile has been successfully updated.