Abstract: This application provides a data transmission method, a communications apparatus, and a session management function entity. The method includes obtaining, by a communications apparatus, a correspondence between a quality of service flow identifier of a service flow and an inter-packet time interval of the service flow. The method also includes establishing, by the communications apparatus based on the correspondence, a gate queue used to send a data packet. The method further includes establishing a mapping relationship between the gate queue and the quality of service flow identifier. The method also includes receiving, by the communications apparatus, a data packet from an upper-level sending device of a transmission link. The method further includes if the data packet includes the quality of service flow identifier, periodically scheduling, by the communications apparatus, the data packet based on the gate queue to which the quality of service flow identifier is mapped.

Abstract: Embodiments of the present disclosure disclose a congestion control method and a related device. The method may include: learning, by an application server from a communications device, that a terminal device has handed over from a source cell to a target cell; detecting, by the application server, a round-trip time RTT and a bandwidth BW; and determining, based on detection values of the RTT and the BW, whether network congestion occurs on the link from the application server to the terminal device. By using this application, in some communication scenarios, a probability that a transmit end enters a network congestion control phase in advance due to erroneous determining may be reduced, and utilization of network bandwidth is improved.

Abstract: A quality of service (QoS) parameter processing method and a system, where the method includes a session management function device obtaining a core network (CN) packet delay budget (PDB) between a first access network device and a first user plane function device, and sending the CN PDB to the first access network device via a context update response message, where the first access network device is a target access network device serving a terminal device after a handover. After receiving the CN PDB, the first access network device determines an access network (AN) PDB between the terminal device and the first access network device based on the CN PDB and an end-to-end PDB between the terminal device and the first user plane function device, and then schedules an air interface resource between the terminal device and the first access network device based on the AN PDB.

Abstract: A quality of service (QoS) parameter processing method and a system, where the method includes obtaining, by a control plane device, a core network (CN) packet delay budget (PDB) between a first access network device and a first user plane function device, sending, by the control plane device, the CN PDB to the first access network device, determining, by the first access network device, an access network (AN) PDB between a terminal device and the first access network device based on the CN PDB and an end-to-end PDB between the terminal device and the first user plane function device, and scheduling, by the first access network device, an air interface resource between the terminal device and the first access network device based on the AN PDB.

Abstract: A communication method includes: a first device obtains transmission states of first n data packets by using a first protocol layer entity, where the first protocol layer entity includes a radio link control (RLC) layer entity or an entity above an RLC layer; the first device starts a timer if transmission states of m data packets in the first n data packets are transmission failures, where n and m are both positive integers, and m is less than or equal to n; and the first device determines a radio resource configuration parameter used to transmit a subsequent data packet, or sends a first message to a second device, where the first message is used to indicate a state of the timer, and the state of the timer is used to determine the radio resource configuration parameter used to transmit the subsequent data packet.

Abstract: Embodiments of this application provide a method, apparatus, and system for determining a synchronization cycle, and relate to the communications field, to determine a proper synchronizing cycle, so that air interface bandwidth resources are saved during clock synchronization in an industrial factory, energy consumption of UE is reduced, and battery power is saved. The method includes: A network device obtains a crystal oscillator frequency offset f1 of UE; the network device obtains a crystal oscillator frequency offset f2 of an AN; the network device obtains a service synchronization precision requirement t of the UE; and the network device calculates a synchronization cycle of clock synchronization between the UE and the AN based on the obtained f1, f2, and t.

Abstract: A synchronization method and an apparatus are provided to meet a time precision requirement of an industrial factory in a scenario in which a mobile network is connected to an Ethernet network. In an embodiment, a first device determines seventh timestamp information by using timestamp information of receiving and sending packets in a mobile network, so that a second device calculates a time offset between the first device and the second device based on the seventh timestamp information and time points of receiving and sending packets in an Ethernet network, to perform time synchronization. In the method, impact of a transmission delay between the first device and the second device can be avoided, so that a time precision requirement of an industrial factory can be met in a scenario in which the mobile network is connected to the Ethernet network.

Abstract: A data packet transmission method includes: obtaining, by a sending device, a data packet; determining, by the sending device, quality of service of the data packet; adding, by the sending device, an identifier and a sequence number to the data packet based on the quality of service of the data packet, where if the quality of service of the data packet belongs to first quality of service, the sending device adds a first identifier and a first sequence number to the data packet; or if the quality of service of the data packet belongs to second quality of service, the sending device adds a second identifier and a second sequence number to the data packet; and sending, by the sending device, the data packet to which the identifier and the sequence number have been added.

Abstract: A quality of service (QoS) parameter processing method and a system, where the method includes obtaining, by a control plane device, a core network (CN) packet delay budget (PDB) between a first access network device and a first user plane function device, sending, by the control plane device, the CN PDB to the first access network device, determining, by the first access network device, an access network (AN) PDB between a terminal device and the first access network device based on the CN PDB and an end-to-end PDB between the terminal device and the first user plane function device, and scheduling, by the first access network device, an air interface resource between the terminal device and the first access network device based on the AN PDB.

Abstract: A quality of service (QoS) parameter processing method and a system, where the method includes obtaining, by a control plane device, a core network (CN) packet delay budget (PDB) between a first access network device and a first user plane function device, sending, by the control plane device, the CN PDB to the first access network device, determining, by the first access network device, an access network (AN) PDB between a terminal device and the first access network device based on the CN PDB and an end-to-end PDB between the terminal device and the first user plane function device, and scheduling, by the first access network device, an air interface resource between the terminal device and the first access network device based on the AN PDB.

Abstract: This application provides a data transmission method, a communications apparatus, and a session management function entity. The method includes obtaining, by a communications apparatus, a correspondence between a quality of service flow identifier of a service flow and an inter-packet time interval of the service flow. The method also includes establishing, by the communications apparatus based on the correspondence, a gate queue used to send a data packet. The method further includes establishing a mapping relationship between the gate queue and the quality of service flow identifier. The method also includes receiving, by the communications apparatus, a data packet from an upper-level sending device of a transmission link. The method further includes if the data packet includes the quality of service flow identifier, periodically scheduling, by the communications apparatus, the data packet based on the gate queue to which the quality of service flow identifier is mapped.

Abstract: This application provides an information transmission method and apparatus. The method includes: determining, by a control device, a first transmission channel in at least one transmission channel configured between a first network device and a second network device, where the first transmission channel is used to transmit a packet that belongs to at least one packet flow, a packet sending frequency currently supported by the first transmission channel is greater than or equal to a sum of packet sending frequencies of the at least one packet flow, and transmission performance of the first transmission channel meets transmission performance of the at least one packet flow; and sending, by the control device, first identification information to the first network device, where the first identification information is used to identify the first transmission channel. Therefore, this helps to meet a requirement for transmission performance of a packet in a mobile network.

Abstract: A method includes: determining, by a terminal device, first indication information, where the first indication information indicates whether the terminal device has a capability of controlling a packet sending frequency; sending, by the terminal device, the first indication information to a control network element; receiving, by the control network element, the first indication information from the terminal device; when the first indication information indicates that the terminal device does not have the capability of controlling the packet sending frequency, sending, by the control network element, a packet sending frequency of a flow to an access network device; receiving, by the access network device, the packet sending frequency of the flow from the control network element; and sending, by the access network device, a packet of the flow based on the packet sending frequency of the flow.

Abstract: Embodiments of the present disclosure disclose a congestion control method and a related device. The method may include: learning, by an application server from a communications device, that a terminal device has handed over from a source cell to a target cell; detecting, by the application server, a round-trip time RTT and a bandwidth BW; and determining, based on detection values of the RTT and the BW, whether network congestion occurs on the link from the application server to the terminal device. By using this application, in some communication scenarios, a probability that a transmit end enters a network congestion control phase in advance due to erroneous determining may be reduced, and utilization of network bandwidth is improved.

Abstract: A data packet transmission method includes: obtaining, by a sending device, a data packet; determining, by the sending device, quality of service of the data packet; adding, by the sending device, an identifier and a sequence number to the data packet based on the quality of service of the data packet, where if the quality of service of the data packet belongs to first quality of service, the sending device adds a first identifier and a first sequence number to the data packet; or if the quality of service of the data packet belongs to second quality of service, the sending device adds a second identifier and a second sequence number to the data packet; and sending, by the sending device, the data packet to which the identifier and the sequence number have been added.

Abstract: Embodiments of the present application provide a method for dynamically creating a local packet data network, an apparatus, and a system. The method includes: receiving a user plane network element selection request, allocating a first user plane network element to UE based on cell location information, a service type, and an access point name of the UE, and then sending a user plane network element response message that carries an identifier of the first user plane network element to a session management network element, so that the session management network element sends a new session establishment request to the first user plane network element.