One-way Frame Delay Measurement
NOTE
IEEE 802.1ag has two versions: IEEE 802.1ag Draft 7 and IEEE Standard 802.1ag-2007. Y.1731 can be
used only on the device complying with IEEE Standard 802.1ag-2007. Therefore, run the cfm version
command to set the 802.1ag version to IEEE Standard 802.1ag-2007 before configuring Y.1731.
One-way frame delay measurement is performed on end-to-end MEPs. A MEP receives a DM
frame and returns a Delay Measurement Reply (DMR) to carry out the one-way frame delay
measurement. As shown in
, the process of one-way frame delay measurement is as
follows:
1.
A MEP periodically sends DM frames carrying TxTimeStampf.
2.
After receiving a DM frame, the remote MEP calculates the one-way frame delay based
on the following formula:
Frame delay = RxTimef - TxTimeStampf
The frame delay variation, namely, frame jitter, can be calculated based on the frame delay.
Jitter: is used as a measure of the variability over time of the frame delay across a network, and
is the absolute difference value between two delays.
Figure 5-2
Networking diagram of the one-way frame delay measurement
MA
MEP1
MEP2
1DM PDU
Y.1731
Two-way Frame Delay Measurement
You can configure the two-way frame delay measurement to collect the statistics of the delay
in bidirectional service traffic transmission.
Figure 5-3
Networking diagram of the two-way frame delay measurement
MA
MEP1
MEP2
DMR
Y.1731
DMM
Quidway S3700 Series Ethernet Switches
Configuration Guide - Reliability
5 ITU-T Recommendation Y.1731 Configuration
Issue 01 (2011-10-26)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
262