Brocade 6910 Ethernet Access Switch Configuration Guide (Supporting R2.2.0.0) - Manual (Page 619)

Brocade 6910 Ethernet Access Switch Configuration Guide 563
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CFM Commands
ethernet cfm loss-measure enable
This command enables periodic transmission of loss-measure messages. Use the no form to
disable transmission.
Syntax
ethernet cfm loss-measure enable {dual-ended | single-ended} md domain-name
ma ma-name mpid source-mpid
no ethernet cfm delay-measure enable md domain-name ma ma-name mpid mpid
domain-name – Domain name. (Range: 1-43 alphanumeric characters)
ma-name – Maintenance association name. (Range: 1-43 alphanumeric characters,
maximum length is 44 minus the length of the domain name)
source-mpid – The identifier of a source MEP that will send loss-measure messages.
(Range: 1-8191)
Default Setting
None
Command Mode
Global Configuration
Command Usage
• A MEP cannot transmit periodic loss-measure and on-demand loss-measure messages at the
same time.
• The CCM PDU carrying dual-ended loss measure information is transmitted at an interval
configured by the
ethernet cfm cc ma interval command. The LMMPDU used for carrying
single-ended loss measure information is transmitting at an interval of 100 ms.
• Dual-ended loss measurement is carried out by sending periodic CCM PDUs with loss
measurement (LM) information to facilitate frame loss measurements at the peer MEP. Each
MEP makes the near-end loss measurements (frame loss associated with ingress data frames)
and far-end loss measurements (frame loss associated with egress data frames).
To perform loss measurement, a MEP periodically transmits CCM frames with the following
elements:
• TxFC1 – Counter for in-profile data frames transmitted towards the peer MEP.
• TxFCf – Value of the local counter TxFC1 at the time of transmission of the CCM frame.
• RxFC1 – Counter for in-profile data frames received from the peer MEP.
• RxFCb – Value of the local counter RxFC1 at the time of reception of the last CCM frame
from the peer MEP.
• TxFCb – Value of TxFCf in the last received CCM frame from the peer MEP.
Upon receiving a CCM frame, a MEP uses the following values to make near-end and far-end
loss measurements:
• Received CCM frame's TxFCf, RxFCb and TxFCb values and local counter RxFC1 value at
the time this CCM frame was received. These values are represented as TxFCf[t
c
],
RxFCb[t
c
], TxFCb[t
c
] and RxFCl[t
c
], where t
c
is the reception time of the current frame.