Ethernet Frame Delay Measurement; Two-Way Ethernet Frame Delay Measurement; Dmm Transmission; Dmr Transmission - Juniper ACX1000 Configuration Manual

ACX Series Universal Access Router Configuration Guide

Two-Way Ethernet Frame Delay Measurement

1118
NOTE: ACX5048 and ACX5096 routers supports only software-based time
stamping for delay measurement.

Ethernet Frame Delay Measurement

Two key objectives of OAM functionality are to measure quality-of-service attributes
such as frame delay and frame delay variation (also known as "frame jitter"). Such
measurements can enable you to identify network problems before customers are
impacted by network defects.
Junos OS supports Ethernet frame delay measurement between MEPs configured on
Ethernet physical or logical interfaces on ACX Series routers. Ethernet frame delay
measurement provides fine control to operators for triggering delay measurement on a
given service and can be used to monitor SLAs. Ethernet frame delay measurement also
collects other useful information, such as worst and best case delays, average delay,
and average delay variation. The Junos OS implementation of Ethernet frame delay
measurement (ETH-DM) is fully compliant with the ITU-T Recommendation Y.1731, OAM
Functions and Mechanisms for Ethernet-based Networks. The recommendation defines
OAM mechanisms for operating and maintaining the network at the Ethernet service
layer, which is called the "ETH layer" in ITU-T terminology.
NOTE: ACX Series routers do not support one-way Ethernet frame delay
measurement.
In two-way ETH-DM mode, frame delay and frame delay variation values are based on
the time difference between when the initiator MEP transmits a request frame and
receives a reply frame from the responder MEP, subtracting the time elapsed at the
responder MEP.

DMM Transmission

When you start a two-way frame delay measurement, the router sends delay
measurement message (DMM) frames— frames that carry the PDU for a two-way
ETH-DM request—from the initiator MEP to the responder MEP at the rate and for the
number of frames you specify. The router marks each DMM frame as drop-ineligible and
inserts a timestamp of the transmission time into the frame.

DMR Transmission

When an MEP receives a DMM frame, the responder MEP responds with a delay
measurement reply (DMR) frame, which carries ETH-DM reply information and a copy
of the timestamp contained in the DMM frame.
Copyright © 2017, Juniper Networks, Inc.