Abstract: A querier election method, a router, and a network system are disclosed. The method includes: a querier starts a sticky-querier-timer; the querier enters the sticky-querier state if the sticky-querier-timer expires; and the querier starts a sticky-query-timer, where the sticky-query-timer is configured to periodically trigger the querier to send a sticky-query message to network devices. With the present invention, the stability of the querier and the network stability can be guaranteed.

Abstract: A method, a device, and a system for protecting a multicast traffic in the field of mobile communication are provided. A backup path is set up for a path that needs to be protected. Route information of the backup path is pre-stored in an entry of a route table. When a failure of the path is detected, a traffic is switched from the failed path to the backup path. By setting up a unicast tunnel or a multicast tunnel as the backup path for a working path in the multicast in advance, and by adding a backup path port as an ingress port of an entry of the route table, it realizes to switch a data flow to the backup path at a forwarding layer without being detected by a user when the working path failure occurs, realizes a fast convergence, and does not influence a user experience, thereby effectively reducing the influence on the user experience when the failed path is restored in a point-to-multipoint service.

Abstract: A fast convergence method, router, and communication system for multicast are disclosed. In the fast convergence method, router, and communication system for multicast, active and standby outgoing interfaces and active and standby next hops for each unicast route reaching a multicast source are calculated, and then active and standby paths are constructed according to the calculated active and standby outgoing interfaces and next hops; when the active path fails, a multicast stream sent by the multicast source is received through the standby path and forwarded; active and standby incoming interfaces and next hops of multicast do not need to be configured on the device statically, which may adapt to dynamic topology changes of the network and greatly expand the multicast stream protection scenarios.

Abstract: A querier election method, a router, and a network system are disclosed. The method includes: a querier starts a sticky-querier-timer; the querier enters the sticky-querier state if the sticky-querier-timer expires; and the querier starts a sticky-query-timer, where the sticky-query-timer is configured to periodically trigger the querier to send a sticky-query message to network devices. With the present invention, the stability of the querier and the network stability can be guaranteed.

Abstract: A method, a device, and a system for protecting a multicast traffic in the field of mobile communication are provided. A backup path is set up for a path that needs to be protected. Route information of the backup path is pre-stored in an entry of a route table. When a failure of the path is detected, a traffic is switched from the failed path to the backup path. By setting up a unicast tunnel or a multicast tunnel as the backup path for a working path in the multicast in advance, and by adding a backup path port as an ingress port of an entry of the route table, it realizes to switch a data flow to the backup path at a forwarding layer without being detected by a user when the working path failure occurs, realizes a fast convergence, and does not influence a user experience, thereby effectively reducing the influence on the user experience when the failed path is restored in a point-to-multipoint service.