Fault Information Advertisement Between EFM and Other Modules

Fault Information Advertisement Between EFM and Detection Modules

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

Figure 1 Fault information advertisement between EFM and detection modules

In Figure 1, fault information advertisement between EFM and detection modules travels over the path: CE5 -> CE4 -> CE1 -> PE2 -> PE4. Table 1 describes the process of fault information advertisement between EFM and detection modules. In particular, it describes function deployments as well as issues and solutions.

**Table 1** Function deployments, issues, and solutions occurring during fault information advertisement between EFM and detection modules
Function Deployment	Issue to Be Resolved	Solution
EFM is configured to monitor the direct link between CE1 and CE4.	PE2 cannot detect a fault on the direct link between CE1 and CE4. As a result, network-side traffic is still sent to CE4, causing traffic interruption. Although Port1 on CE1 goes Down, it cannot notify CE4 of the fault. As a result, CE4 still forwards user traffic to CE1, causing traffic interruption.	EFM and Port1 are associated with each other. If a fault occurs, traffic switches to a standby link between CE1 and CE5. If EFM detects a fault on a direct link between CE1 and CE4, EFM instructs the OAMMGR module to notify Port1 of the fault. After receiving the notification, Port1 changes its physical status to TRIGGER DOWN (3AH). If Port1 goes Down, it instructs the OAMMGR module to notify the EFM module of the fault. After receiving the notification, EFM notifies CE4 of the fault.
EFM is used to monitor direct links between CE5 and CE4 and between CE4 and CE1.	Although EFM detects a fault on a direct link between CE5 and CE4, it cannot notify CE1 of the fault. As a result, CE1 still forwards network traffic to CE4, causing traffic interruption.	EFM modules for monitoring these two direct links can be associated. If an EFM module detects a fault, it instructs the OAMMGR module to notify the other EFM module of the fault. An EFM module can be associated with Port1 on CE1. If the EFM module detects a fault on the link between CE5 and CE4, the EFM module advertises fault information to another EFM module for monitoring the link between CE1 and CE4. Port1 that is associated with the EFM module is also notified. The association prevents network traffic from being interrupted on CE4.
EFM is used to monitor a direct link between CE1 and PE2, and CFM is used to monitor a link between PE2 and PE6.	Although EFM detects a fault, EFM cannot notify PE6 of the fault. As a result, traffic is still sent to PE6, causing traffic interruption. Although CFM detects a fault, CFM cannot notify CE1 of the fault. As a result, CE1 still forwards user traffic to PE2, causing traffic interruption.	The EFM module can be associated with the CFM module. If the CFM module detects a fault, it instructs the OAMMGR module to notify the EFM module of the fault. If the EFM module detects a fault, it instructs the OAMMGR module to notify the CFM 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.
EFM is used to monitor a direct link between CE1 and PE2, and BFD is used to monitor a link between PE2 and PE6.	Although EFM detects a fault, EFM cannot notify PE6 of the fault. As a result, traffic is still sent to PE6, causing traffic interruption. Although BFD detects a fault, EFM cannot notify CE1 of the fault. As a result, CE1 still forwards user traffic to PE2, causing traffic interruption.	The EFM module can be associated with the BFD module. If the EFM module detects a fault, it instructs the OAMMGR module to notify the BFD module of the fault. If the BFD 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.