Ethernet Synthetic Loss Measurement Overview - Juniper ACX1000 Configuration Manual

ACX Series Universal Access Router Configuration Guide
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Ethernet Synthetic Loss Measurement Overview

1140
}
action {
log-and-generate-ais {
level 1...n;
interval 1 second | 1 minute;
priority dot1p [range 0-7];
}
}
}
To attach an action profile to a server MEP, include the following statement at the [edit
protocols oam ethernet connectivity-fault-management] hierarchy level:
[edit protocols oam ethernet connectivity-fault-management]
server-mep mep-identifier {
protocol l2circuit | l2vpn | ethernet {
interface interface-name;
}
action-profile action-profile-name;
}
Ethernet Alarm Indication Signal Overview on page 1136
Ethernet synthetic loss measurement (ETH-SLM) is an application that enables the
calculation of frame loss by using synthetic frames instead of data traffic. This mechanism
can be considered as a statistical sample to approximate the frame loss ratio of data
traffic. Each maintenance association end point (MEP) performs frame loss
measurements, which contribute to unavailable time.
A near-end frame loss specifies frame loss associated with ingress data frames and a
far-end frame loss specifies frame loss associated with egress data frames. Both near-end
and far-end frame loss measurements contribute to near-end severely errored seconds
and far-end severely errored seconds that are used in combination to determine
unavailable time. ETH-SLM is performed using synthetic loss message (SLM) and
synthetic loss reply (SLR) frames. ETH-SLM facilitates each MEP to perform near-end
and far-end synthetic frame loss measurements by using synthetic frames because a
bidirectional service is defined as unavailable if either of the two directions is determined
to be unavailable.
There are the two types of frame loss measurement, defined by the ITU-T Y.1731 standards,
ETH-LM and ETH-SLM. Junos OS supports only single-ended ETH-SLM. In single-ended
ETH-SLM, each MEP sends frames with the ETH-SLM request information to its peer
MEP and receives frames with ETH-SLM reply information from its peer MEP to perform
synthetic loss measurements. Single-ended ETH-SLM is used for proactive or on-demand
OAM to perform synthetic loss measurements applicable to point-to-point Ethernet
connection. This method allows a MEP to initiate and report far-end and near-end loss
measurements associated with a pair of MEPs that are part of the same maintenance
entity group (MEG).
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