Abstract: A method for detecting quality of service of a service includes obtaining, by a packet sending device, detection indication information, where the detection indication information is used to instruct the packet sending device to detect quality of service of a service; and sending, by the packet sending device, a detection packet to a packet receiving device based on the detection indication information, where the detection packet is used to detect the quality of service of the service.

Abstract: A communication method, an apparatus, and a system in which a first session management function entity based on information of a terminal group determines user plane function entities accessed by terminals in a terminal group, and the first session management function entity determines a target user plane function entity based on the user plane function entities, where the target user plane function entity is used to perform communication between terminals in the terminal group. According to the method, the terminals in the terminal group are redirected to a same user plane function entity, namely, the target user plane function entity, so that communication between the terminals in the terminal group is locally implemented in the target user plane function entity. This shortens a communication path, and reduces a communication latency.

Abstract: A service continuity implementation method, a device, and a service continuity implementation system, to ensure service continuity in a handover process, where the method includes: selecting, by a session management function entity, a target user plane function entity to serve a terminal; sending, by the session management function entity, a first message to a control device; receiving, by the session management function entity, indication information of a first application server (AS) from the control device; and sending, by the session management function entity, a first routing rule to the target user plane function entity based on the indication information of the first AS, where the first routing rule specifies that data whose destination address is an address of the first AS is to be sent to the first AS.

Abstract: A method and an apparatus for initiating user plane path re-establishment and a communications system are disclosed. The method includes: determining, by a session management function entity based on first location information of a terminal device, a session service area to which a current session of the terminal device belongs; and after receiving second location information of the terminal device sent by a mobility management function entity, if determining that the second location information is not within the session service area, instructing the terminal device to initiate a re-establishment procedure for the current session or initiate a handover procedure. Due to introduction of the session service area, when the terminal device moves back and forth at edges of service areas of two adjacent user plane function entities, a ping-pong effect caused by frequent handover between the two user plane function entities is avoided, and user experience is improved.