The Design And Implementation Of Connectivity Fault Detect Protocol Module

With the developing of the Ethernet technology, it is not used in LAN, but also in theMAN and WAN. Because there are many of different users that require sophisticatedneeds in the MAN and WAN, so it needs different operators to work together to provideend-to-end business. There are many requests about security, scalability, manageability ofthe Ethernet because it is playing more and more important role in the network. At thebeginning, the Ethernet was designed for the LAN. Because the LAN itself has a highreliability and stability, so the mechanism of managing and maintaining the Ethernet wasnot built. Compared to the LAN, the link length and the size of the MAN and WAN arerapidly expanding. Hence the lack of effective management and maintenance mechanismof the Ethernet, it has become a serious obstacle in the MAN and WAN applications.Therefore, the Ethernet OAM technology is becoming focus in the use of telecom.CFD agreement is an end-to-end Ethernet OAM mechanism based on VLAN tocheck the connectivity of the layer2link, which follows the IEEE802.1ag of CFM(Connectivity Fault Management) protocol and the ITU-T Y.1731protocol. It provideseight level maintenance domains, the network administrator can divide Ethernet serviceproviders into different levels for management. When a network failure happens, CFD canquickly locate where the failure to restore the normal operation of the network based onthe functions of CCM, LB and LT. The CFD module based on Comware V7system ofH3C’s switch is divided into six sub-modules: configuration process module、eventprocess module、protocol process module、data management module、backup processmodule and proxy process module. It uses them to respond to the event messages thatcome from user configuration commands、interface management module、aggregationmodule、MSTP module、VLAN module and Ethernet module in system, and changes itsown status according to the messages to monitor the connectivity of the link. The implementation of the Connectivity Fault Detect protocol on the switch canprovide the tool of monitoring and resolving problems to the operation and maintenancepersons. According to the correct configuration, it can show all the indicators of thenetwork. Because of the technology, the era of the Ethernet is coming.