Two-way delay measurement is similar to one way delay measurement except it measures the round trip delay from the generating MEP. In this case wall clock synchronization issues will not influence the test results because four timestamps are used. This allows the remote nodes time to be removed from the calculation and as a result clock variances are not included in the results. The same consideration for first test and hardware based time stamping stated for one way delay measurement are applicable to two-way delay measurement.
Delay can be measured using one-way and two-way on demand functions. The two-way test results are available single-ended, test initiated, calculation and results viewed on the same node. There is no specific configuration under the MEP on the SAP to enabled this function. The latest test result is stored for viewing. Further tests will overwrite the previous results. Delay Variation is only valid if more than one test has been executed.
oam eth-cfm two-way-delay-test d0:0d:1e:00:01:02 mep 101 domain 4 association 1
Two-Way-Delay-Test Response:
Delay 2955 microseconds Variation 111 microseconds
# show eth-cfm mep 101 domain 4 association 1 two-way-delay-test
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Eth CFM Two-way Delay Test Result Table
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Peer Mac Addr Delay (us) Delay Variation (us)
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d0:0d:1e:00:01:02 2955 111