Technical Documentation

Starting an ETH-DM Session

Using the monitor ethernet delay-measurement Command

After you have configured two MX Series routers to support ITU-T Y.1731Ethernet frame delay measurement (ETH-DM), you can initiate a one-way or two-way Ethernet frame delay measurement session from the CFM maintenance association end point (MEP) on one of the routers to the peer MEP on the other router.

To start an ETH-DM session between the specified local MEP and the specified remote MEP, enter the monitor ethernet delay-measurement command at operational mode. The syntax of the command is as follows:

monitor ethernet delay-measurement(one-way | two-way)maintenance-domain md-namemaintenance-association ma-name(remote-mac-address | mep remote-mep-id)<count frame-count><wait interval-seconds>

For a one-way frame delay measurement, the command displays a runtime display of the number of 1DM frames sent from the initiator MEP during that ETH-DM session. One-way frame delay and frame delay variation measurements from an ETH-DM session are collected in a CFM database at the router that contains the receiver MEP. You can retrieve ETH-DM statistics from a CFM database at a later time.

For a two-way frame delay measurement, the command displays two-way frame delay and frame delay variation values for each round-trip frame exchange during that ETH-DM session, as well as a runtime display of useful summary information about the session: average delay, average delay variation, best-case delay, and worst-case delay. Two-way frame delay and frame delay variation values measurements from an ETH-DM session are collected in a CFM database at the router that contains the initiator MEP. You can retrieve ETH-DM statistics from a CFM database at a later time.

Note: Although you can trigger frame delay collection for up to 65,535 ETH-DM requests at a time, a router stores only the last 100 frame delay statistics per CFM session (pair of peer MEPs).

For a complete description of the monitor ethernet delay-measurement operational command, see the JUNOS System Basics and Services Command Reference.

Starting a One-Way ETH-DM Session

To start a one-way Ethernet frame delay measurement session, enter the monitor ethernet delay-measurement one-way command from operational mode, and specify the peer MEP by its MAC address or by its MEP identifier.

For example:


user@host> monitor ethernet delay-measurement one-way 00:05:85:73:39:4a maintenance-domain md6 maintenance-association ma6 count 10
One-way ETH-DM request to 00:05:85:73:39:4a, Interface xe-5/0/0.0
1DM Frames sent : 10
--- Delay measurement statistics ---
Packets transmitted: 10
Average delay: NA, Average delay variation: NA
Best case delay: NA, Worst case delay: NA

Note: If you attempt to monitor delays to a nonexistent MAC address, you must type Ctrl + C to explicitly quit the monitor ethernet delay-measurement command and return to the CLI command prompt.

Starting a Two-Way ETH-DM Session

To start a two-way Ethernet frame delay measurement session, enter the monitor ethernet delay-measurement two-way command from operational mode, and specify the peer MEP by its MAC address or by its MEP identifier.

For example:


user@host> monitor ethernet delay-measurement two-way 00:05:85:73:39:4a maintenance-domain md6 maintenance-association ma6 count 10
Two-way ETH-DM request to 00:05:85:73:39:4a, Interface xe-5/0/0.0
DMR received from 00:05:85:73:39:4a Delay: 100 usec Delay variation: 0 usec
DMR received from 00:05:85:73:39:4a Delay: 92 usec Delay variation: 8 usec
DMR received from 00:05:85:73:39:4a Delay: 92 usec Delay variation: 0 usec
DMR received from 00:05:85:73:39:4a Delay: 111 usec Delay variation: 19 usec
DMR received from 00:05:85:73:39:4a Delay: 110 usec Delay variation: 1 usec
DMR received from 00:05:85:73:39:4a Delay: 119 usec Delay variation: 9 usec
DMR received from 00:05:85:73:39:4a Delay: 122 usec Delay variation: 3 usec
DMR received from 00:05:85:73:39:4a Delay: 92 usec Delay variation: 30 usec
DMR received from 00:05:85:73:39:4a Delay: 92 usec Delay variation: 0 usec
DMR received from 00:05:85:73:39:4a Delay: 108 usec Delay variation: 16 usec

--- Delay measurement statistics ---
Packets transmitted: 10, Valid packets received: 10
Average delay: 103 usec, Average delay variation: 8 usec
Best case delay: 92 usec, Worst case delay: 122 usec

Note: If you attempt to monitor delays to a nonexistent MAC address, you must type Ctrl + C to explicitly quit the monitor ethernet delay-measurement command and return to the CLI command prompt.


Published: 2010-04-20