CFM loopback, linktrace, and two-way delay measurement tests (ETH-DM) can be initiated using SAA. Additional timestamping is required for loopback and linktrace tests. An organization-specific TLV is used on both sender and receiver nodes to carry the timestamp information. Currently, timestamps are only applied by the sender node. This means that any time measurements resulting from the loopback and linktrace tests include the packet processing time used by the remote node. Because ETH-DM uses a four timestamp approach to remove the remote processing time, it should be used for accurate delay measurements.
The SAA versions of the CFM loopback, linktrace, and ETH-DM tests support send-count, interval, timeout, and FC. The summary of the test results are stored in an SAA accounting file.
The 7705 SAR supports SAA-triggered ETH-DM tests for both Y.1731 and 802.1ag MEPs for Ethernet SAPs (Epipe and VPLS) and facility MEPs on network interfaces.