Fault Information Advertisement Between CFM and Other Modules

Fault Information Advertisement Between CFM and Detection Modules

The OAMMGR module associates CFM with detection modules. The detection modules include EFM, BFD, and interface. Figure 1 shows a network on which fault information is advertised between CFM and detection modules.

Figure 1 Fault information advertisement between CFM and detection modules

Table 1 describes problems and solutions for fault information advertisement between CFM and detection modules over the path UPE1 -> PE2 -> PE4 -> PE6 -> PE8.

**Table 1** Problems and solutions for fault information advertisement
Function Deployment	Problem	Solution
CFM is used to monitor the link between UPE1 and PE4.	Although CFM detects a fault on the link between UPE1 and PE4, CFM cannot notify PE6 of the fault. As a result, network-side traffic is still sent to PE4, interrupting traffic. Although Port1 on PE4 goes Down, Port1 cannot notify CE1 of the fault. As a result, CE1 continues forwarding user traffic to PE4, interrupting traffic.	Associate CFM with Port1: If CFM detects a fault, it instructs the OAMMGR module to disconnect Port1 intermittently. This operation allows other modules to detect the fault. If Port1 goes Down, it instructs the OAMMGR module to notify CFM of the fault. After receiving the notification, CFM notifies PE6 of the fault. The association between CFM and an interface is used to detect faults in an active link of a link aggregation group (LAG) in static LACP or 1:1 active/standby mode. If a fault is detected, a protection switchover is triggered.
EFM is used to monitor the direct link between CE1 and UPE1. CFM is used to monitor the link between PE4 and UPE1.	Although CFM detects a fault, CFM cannot notify CE1 of the fault. As a result, CE1 continues forwarding user traffic to PE4, interrupting traffic.	Associate the EFM module with the CFM module: If the EFM module detects a fault, it instructs the OAMMGR module to notify the CFM module of the fault. If the CFM module detects a fault, it instructs the OAMMGR module to notify the EFM module of the fault. The association allows a module to notify another associated module of a fault and send a trap to the NMS. A network administrator analyzes alarm information and takes measures to rectify the fault.
CFM is configured to monitor links between UPE1 and PE4 and between PE4 and PE8.	Although CFM detects a fault in the link between PE4 and PE8, it cannot notify UPE1 of the fault. As a result, CE1 does not detect the fault, interrupting traffic. Although CFM detects a fault in the link between UPE1 and PE4, it cannot notify PE8 of the fault. As a result, PE8 continues forwarding network traffic to PE4 through PE6, interrupting traffic.	Associate both CFM modules with each other: If a CFM module detects a fault, it instructs the OAMMGR module to notify the other CFM module of the fault and sends an alarm to an NMS. A network administrator analyzes alarm information and takes measures to rectify the fault.