Abstract: This application discloses a network topology discovery method and a node device. In this application, a root node device sends a link discovery message to a child node device through a first port; receives a link discovery acknowledge message sent by the child node device through a second port of the child node device, where the link discovery acknowledge message includes an identifier of the child node device and an identifier of the second port; and determines a first link based on the link discovery acknowledge message, where the first link is a link between the first port and the second port. According to the solutions of this application, when detecting that a link of a port is connected, the node device discovers an existing topology relationship through message interaction, so as to implement network topology discovery.

Abstract: This application provides a service transmission method and an apparatus. Service queues of a first communication apparatus contend for a channel. A service queue obtains the channel through contention to obtain a data transmission opportunity. The first communication apparatus transmits data of a highest-priority service queue of the first communication apparatus in a time window corresponding to the transmission opportunity. According to the technical solutions provided in this application, the data of the highest-priority service queue can be preferably transmitted, to reduce waiting time of the highest-priority service queue and reduce service latency.

Abstract: This application relates to the field of wireless fidelity technologies, and in particular, to a channel access method and a communication apparatus. The method includes: A first access point sends a management frame to a first device, where the management frame includes first indication information, the first indication information indicates at least one first reserved resource that first traffic is allowed to contention-based access, and the at least one first reserved resource only includes a time-frequency resource; and then the first device initiates channel access on the at least one first reserved resource, and transmits the first traffic. Because the at least one first reserved resource is specially reserved for the first traffic, it may be considered that traffic other than the first traffic does not contention-based access the at least one first reserved resource.

Abstract: This application discloses a network topology discovery method and a node device. In this application, a root node device sends a link discovery message to a child node device through a first port; receives a link discovery acknowledge message sent by the child node device through a second port of the child node device, where the link discovery acknowledge message includes an identifier of the child node device and an identifier of the second port; and determines a first link based on the link discovery acknowledge message, where the first link is a link between the first port and the second port. According to the solutions of this application, when detecting that a link of a port is connected, the node device discovers an existing topology relationship through message interaction, so as to implement network topology discovery.