System and method for protecting UNI through NNI based on LTE base station return services

The invention discloses a system and method for protecting a UNI through an NNI based on LTE base station return services, and relates to the protection field of LTE base station return services. BFD is configured on PW services, and the PW services are correlated with a BDF through BFD_ID. When the network on a user side fails, the BFD is configured on the PW services, in this way, the BFD of the PW services can rapidly notify A2 and B1 of failure information; in the service downlink direction, according to failed router information which B1 and the BFD_ID find, B1 upgrades a sub-optimal host router corresponding to a failure router to an optimal host router. Rapid service switching is achieved through protecting a UNI side chain link with an NNI side chain link, then the number of lost packets when a user side chain link fails is effectively decreased, in this way, the stability of network transmission can be improved, switching time of services in the downlink direction can be shortened, and the system and method are convenient to use for people.