Huawei NetEngine80E Configuration Manual - Reliability page 731

HUAWEI NetEngine80E/40E Router
Configuration Guide - Reliability
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As shown in
monitoring for end-to-end services. When a user considers that the quality of purchased Ethernet
tunnel services deteriorates or when an operator needs to conduct regular Service level agreement
(SLA) monitoring.
Basic Concepts and Principles
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Issue 02 (2014-09-30)
802.3ah, also known as Ethernet in the First Mile (EFM), is used to monitor the first-mile
link connectivity. It is a type of link-level OAM technology. EFM provides link
connectivity detection, link fault monitoring, remote fault notification, and remote
loopback for two directly connected devices.
IEEE 802.1ag, also known as Connectivity Fault Management (CFM), defines OAM
functions, such as continuity check (CC), link trace (LT) and loopback (LB), for Ethernet
networks. CFM is network-level OAM and is applicable to large-scale end-to-end
networking.
Y.1731 is an OAM protocol defined by the ITU-T. It covers the contents defined by IEEE
802.1ag and other OAM functions, including the Alarm Indication Signal (AIS), Remote
Defect Indication (RDI), Locked Signal (LCK), Test Signal, Automatic Protection
Switching (APS), Maintenance Communication Channel (MCC), Experimental OAM
(EXP), and Vendor Specific OAM (VSP) for fault management and frame loss
measurement (LM) and delay measurement (DM) for performance monitoring.
Figure 8-39, Y.1731 is used to implement fast fault detection and performance
Single-ended frame loss measurement
Frame loss measurement is performed by sending frames with ETH-LM information to a
remote Maintenance association End Point (MEP) and receiving frames with ETH-LM
information from the remote MEP. As shown in
frame loss measurement is as follows:
1. The local MEP(Maintenance association End Point) sends an ETH-LMM (a frame
containing ETH-LM request information) to the remote MEP. The ETH-LMM carries
a transmit counter indicating the time at which the message is sent by the local end.
2. After receiving the ETH-LMM, the remote MEP replies with an ETH-LMR (a frame
containing ETH-LM response information).
3. After receiving the ETH-LMR, the local MEP obtains corresponding measurement
information based on message contents and calculates the frame loss ratio.
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8 Ethernet OAM Configuration
Figure 8-40, the process of single-ended
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