| 摘要 |
A method of transmitting and receiving multicast data is provided to utilize wireless resource effectively by transmitting IGMP(Internet Group Management Protocol) report as an AP(Access Point) instead of each mobile terminal, and preventing unnecessary multicast data transmission. A multicast router offers multicast service information to all APs through IGMP query(S801). If a mobile terminal wants to get the multicast service, the multicast router transmits a service activation request operation frame to the AP, at this time, a multicast MAC address about the multicast service is transmitted together(S802). The AP writes information about the mobile terminals into a multicast group table, wherein a multicast address and an expiration time are set according to the service activation request operation frame(S803). The AP joins the multicast service by sending a IGMP report to the multicast router, and the multicast router describes that the AP requires the multicast service in a multicast group membership list(S804). Other mobile terminals can send the service activation request, and the APs can respond(S805). The AP verifies the multicast group table(S810'). The AP determines bearer types according to the number of terminals(S810''). The multicast router sends the IGMP query to each AP(S811). The AP receives the IGMP query, and if the multicast service request exists in the multicast group table, the AP sends an IGMP report, otherwise the AP sends an IGMP leave report(S812). The AP sends a keep alive request periodically to maintain the multicast group table(S813).
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