Connection establishment method, device, and system

A connection establishment method comprising:

• receiving, by a network device, first authentication information from a first user equipment, wherein the first authentication information comprises an identifier of a second group of served objects for which a second user equipment provides a relay service, and the identifier of the second group is used to indicate a group of user equipment to which a second user equipment belongs or a group of users to which a user of the second user equipment belongs;
• obtaining, by the network device, a served object group identifier of the first user equipment, wherein the served object group identifier of the first user equipment is used to indicate a first group of served objects for which the first user equipment provides a relay service;
• when the served object group identifier of the first user equipment comprises the identifier of the second group, sending, by the network device, first authentication acknowledgement information to the first user equipment, wherein the first authentication acknowledgement information is used to instruct the first user equipment to provide the relay service for the second user equipment;
• and
• sending, by the network device, a data link layer identity (ID) of the second user equipment to the first user equipment, wherein the data link layer ID of the second user equipment is used to establish a connection between the first user equipment and the second user equipment.

A first user equipment comprising a processor, a memory, a bus, and a receiver, wherein the processor, the memory, and the receiver are connected to each other by using the bus;

• the receiver is configured to cooperate with the processor to receive a served object group identifier from a network device, wherein the served object group identifier is used to indicate a first group of served objects for which the first user equipment provides a relay service;
• the receiver is further configured to cooperate with the processor to receive discovery information from a second user equipment,
• wherein the discovery information comprises a data link layer identity (ID) of the second user equipment an identifier of a second group of served objects for which the second user equipment provides a relay service and a relay service request, the relay service request is used to request the relay service, and
• the identifier of the second group is used to indicate a group of user equipment to which the second user equipment belongs or a group of users to which a user of the second user equipment belongs;
• and
• the processor is configured to, when the served object group identifier comprises the identifier of the second group received by the receiver, obtain the data link layer ID of the second user equipment from the discovery information, and establish a connection between the first user equipment and the second user equipment according to the data link layer ID of the second user equipment.

A network device comprising a processor, a memory, a bus, a receiver, and a transmitter, wherein the processor, the memory, the receiver, and the transmitter are connected to each other by using the bus;

• the receiver is configured to cooperate with the processor to receive first authentication information from a first user equipment, wherein the first authentication information comprises an identifier of a second group of served objects for which the second user equipment provides a relay service, and the identifier of the second group is used to indicate a group of user equipment to which a second user equipment belongs or a group of users to which a user of the second user equipment belongs;
• the processor is configured to obtain a served object group identifier of the first user equipment, wherein the served object group identifier of the first user equipment is used to indicate a group of served objects for which the first user equipment provides a relay service;
• and
• the transmitter is configured to, when the served object group identifier obtained by the processor comprises the identifier of the second group received by the receiver, cooperate with the processor to send (a) a data link layer identifier (ID) of the second user equipment and (b) first authentication acknowledgement information to the first user equipment, wherein the data link layer ID of the second user equipment is used to establish a connection between the first user equipment and the second user equipment and the first authentication acknowledgement information is used to instruct the first user equipment to provide the relay service for the second user equipment.