A network device that supports a WLAN communication function, wherein the network device comprises a processing unit and a transceiver unit , wherein the transceiver unit comprises multiple antenna interfaces , and the network device is configured to operate with multiple basic service sets, wherein at least two basic service sets correspond to different antenna interfaces , the processing unit is configured to generate a correspondence information element, wherein the correspondence information element comprises correspondence indication information, and the correspondence indication information is used to indicate correspondences between the basic service sets and the antenna interfaces ; and the transceiver unit is configured to send the correspondence information element to a station that supports the WLAN communication function, wherein at least two basic service sets in the multiple basic service sets belong to one fast roaming group, and the transceiver unit is further configured to send a fast roaming information element to the station, wherein the fast roaming information element comprises fast roaming grouping indication information, and the fast roaming grouping indication information is used to indicate basic service sets comprised in the fast roaming group, so that when the station switches association in multiple basic service sets in a same fast roaming group, the station does not need to disassociate with a basic service set before switching, and does not need to authenticate a basic service set after switching, but the station directly switches to and associates with one basic service set in the fast roaming group to another basic service set in the fast roaming group, to implement fast roaming, and wherein the fast roaming information element and the correspondence indication information are carried in a same management frame for sending. the processing unit is configured to generate a correspondence information element, wherein the correspondence information element comprises correspondence indication information, and the correspondence indication information is used to indicate correspondences between the basic service sets and the antenna interfaces ; and the transceiver unit is configured to send the correspondence information element to a station that supports the WLAN communication function, wherein at least two basic service sets in the multiple basic service sets belong to one fast roaming group, and the transceiver unit is further configured to send a fast roaming information element to the station, wherein the fast roaming information element comprises fast roaming grouping indication information, and the fast roaming grouping indication information is used to indicate basic service sets comprised in the fast roaming group, so that when the station switches association in multiple basic service sets in a same fast roaming group, the station does not need to disassociate with a basic service set before switching, and does not need to authenticate a basic service set after switching, but the station directly switches to and associates with one basic service set in the fast roaming group to another basic service set in the fast roaming group, to implement fast roaming, and wherein the fast roaming information element and the correspondence indication information are carried in a same management frame for sending. <EOS>