HP 5130 EI Series Configuration Manual page 23

NOTE:
This function is supported only by Release 3108P01 and later versions.
LM
The LM function measures the frame loss in a certain direction between a pair of MEPs. The source MEP
sends loss measurement messages (LMMs) to the target MEP. The target MEP responds with loss
measurement replies (LMRs). The source MEP calculates the number of lost frames according to the
counter values of the two consecutive LMRs (the current LMR and the previous LMR). LMMs and LMRs are
unicast frames.
NOTE:
This function is supported only by Release 3108P01 and later versions.
DM
The DM function measures frame delays between two MEPs, including the following types:
• One-way frame delay measurement
The source MEP sends a one-way delay measurement (1DM) frame, which carries the transmission
time, to the target MEP. When the target MEP receives the 1DM frame, it does the following:
Records the reception time.
Calculates and records the link transmission delay and jitter (delay variation) according to the
transmission time and reception time.
1DM frames are unicast frames.
• Two-way frame delay measurement
The source MEP sends a delay measurement message (DMM), which carries the transmission time,
to the target MEP. When the target MEP receives the DMM, it responds with a delay measurement
reply (DMR). The DMR carries the reception time and transmission time of the DMM and the
transmission time of the DMR. When the source MEP receives the DMR, it does the following:
Records the DMR reception time.
Calculates the link transmission delay and jitter according to the DMR reception time and DMM
transmission time.
DMM frames and DMR frames are unicast frames.
NOTE:
This function is supported only by Release 3108P01 and later versions.
TST
The TST function tests the bit errors between two MEPs. The source MEP sends a TST frame, which carries
the test pattern, such as pseudo random bit sequence (PRBS) or all-zero, to the target MEP. When the
target MEP receives the TST frame, it determines the bit errors by calculating and comparing the content
of the TST frame. TST frames are unicast frames.
NOTE:
This function is supported only by Release 3108P01 and later versions.
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