PROTECTION METHOD FOR A DOWNLINK FLOW HANDOVER WHEN A USER ACCESSES A BACKUP AND BACKUP FORWARDING SYSTEM THEREOF

摘要

A protection method for a downlink flow handover when a user accesses a backup is provide in the present invention and a system thereof. The method includes that: a backup next-hop for a user address is configured in a main Service Node (SN), and the backup next-hop points to the backup SN of the main SN; when detecting a downlink failure of the main SN, the main SN executes a handover to a backup state, and transmits return flow which is from the network side to the user side to the backup SN via the backup next-hop during a routing convergence, then the backup SN forwards the return flow to the user. The system includes the main SN, the backup SN corresponding to the main SN, and an access node. The method and system in the present invention avoid the loss of the user downlink flow during the backup SN refreshes a user route to an upper network.