"FD 100/320Gbps NT and FX NT IHub SystemBasics, Management and OAM Guide"Ethernet Connection Fault ManagementIssue: 10 3HH-11982-AAAA-TQZZA 1738.3 LoopbackA loopback message is generated by an MEP to its peer MEP or a MIP (Figure 5).The functions are similar to an IP ping to verify Ethernet connectivity between thenodes.Figure 5 CFM LoopbackThe following loopback-related functions are supported:• Loopback message functionality on an MEP or MIP can be enabled or disabled.• MEP - Supports generating unicast and multicast loopback messages andresponding to loopback messages with loopback reply messages.• MEP - Supports generating unicast loopback messages with Test TLV containinga PRBS pattern with CRC 32 and evaluating if the CRC pattern on the receivedloopback reply message matches the CRC pattern sent on the loopback message• MIP - Supports responding to loopback messages with loopback reply messageswhen loopback messages are targeted to self.• Displays the loopback test results on the originating MEP8.4 LinktraceA linktrace message is originated by an MEP and targeted to a peer MEP in the sameMA and within the same MD level (Figure 6). Its function is similar to IP traceroute.Traces a specific MAC address through the service. The peer MEP responds with alinktrace reply message after successful inspection of the linktrace message. TheMIPs along the path also process the linktrace message and respond with linktracereplies to the originating MEP if the received linktrace message has a TTL greaterthan 1 and forward the linktrace message if a look up of the target MAC address inthe Layer 2 FIB is successful. The originating MEP shall expect to receive multiplelinktrace replies and from processing the linktrace replies, it can put together theroute to the target bridge.
