With the development of mobile communications technologies, a user may access a wide area network (WAN) in multiple manners. For example, a WAN port on a mobile wireless interconnection (Wireless Fidelity, WiFi) device may include an Ethernet port, a WiFi station (Station, STA) port, and a 3G/4G (third generation/fourth generation of mobile telecommunications technology) port, and the user may access the WAN by using any one of the three ports. However, when the user performs data transmission by using the 3G/4G port, it may result in relatively high burden on an operator's network and may cause a problem of a relatively high tariff. Different from an operator's network, a local area network (LAN) usually accesses a wired network, for example, accesses an optical fiber network, by using a WiFi network. The WiFi network has features such as high performance and a low tariff. Therefore, resources of two networks may be coordinated in a unified manner. After entering an area covered by a WiFi network, a mobile WiFi device can automatically hand over to the WiFi network by using a WiFi hotspot and accesses the Internet by using the WiFi network, whereas the mobile WiFi device hands over back to the 3G/4G network only when no nearby WiFi hotspot is available.
At present, most mobile WiFi devices use a single-chip WiFi solution to implement WiFi uplink and downlink functions, and use a channel follow-up policy. After a WiFi uplink connects to a new operator's access point (AP), an AP in the mobile WiFi device also follows the WiFi uplink channel to switch its own channel, that is, the uplink and the downlink remain in a same operating channel; therefore when the mobile WiFi device switches the channel, a service of an STA, such as a PC (computer), which is connected to the mobile WiFi device, may be interrupted for a period of time.