Communication method, apparatus, and system

1. A communication method, the method comprising:

receiving, by a terminal device, first clock source information, wherein the first clock source information corresponds to clock source information of a wireless communication system, wherein the first clock source information indicates that a fifth generation (5G) system clock is useable as a clock source;

sending, by the terminal device, the first clock source information to an adjacent device;

receiving, by the terminal device, a clock synchronization packet from a user plane network element, wherein the clock synchronization packet comprises a first timestamp, and the first timestamp represents a first time at which the user plane network element sends the clock synchronization packet;

determining, by the terminal device, a forwarding delay of the clock synchronization packet in the wireless communication system based on the first timestamp and a second time at which the terminal device forwards the clock synchronization packet; and

after adding the forwarding delay to a correction field in the clock synchronization packet, sending, by the terminal device, the clock synchronization packet to the adjacent device at the second time at which the terminal device forwards the clock synchronization packet.

2. The method according to claim 1 , wherein receiving the first clock source information comprises:

receiving, by the terminal device, a first clock source announcement from the user plane network element, wherein the first clock source announcement comprises the first clock source information.

3. The method according to claim 2 , wherein sending the first clock source information to the adjacent device comprises:

sending, by the terminal device, the first clock source announcement to the adjacent device.

4. The method according to claim 1 , wherein receiving the first clock source information comprises:

receiving, by the terminal device, the first clock source information from a control plane network element, wherein the control plane network element corresponds to a network exposure function network element.

5. The method according to claim 4 , wherein sending the first clock source information to the adjacent device comprises:

generating, by the terminal device, a sixth clock source announcement based on the first clock source information, wherein the sixth clock source announcement comprises the first clock source information; and

sending, by the terminal device, the sixth clock source announcement to the adjacent device.

6. The method according to claim 4 , the method further comprising:

generating, by the terminal device, a clock synchronization packet in response to the clock source corresponding to the first clock source information is an optimal clock source, and

sending the clock synchronization packet to the adjacent device.

7. A communication apparatus, comprising:

an interface;

a non-transitory memory configured to store non-transitory instructions; and

at least one processor in communication with the interface and the non-transitory memory, and in response to being executed by the at least one processor, the non-transitory instructions cause the at least one processor to:

receive, by the interface, first clock source information, wherein the first clock source information corresponds to clock source information of a wireless communication system, wherein the first clock source information indicates that a fifth generation (5G) system clock is useable as a clock source;

send, by the interface, the first clock source information to an adjacent device;

receive, by the interface, a clock synchronization packet from a user plane network element, wherein the clock synchronization packet comprises a first timestamp, and the first timestamp represents a first time at which the user plane network element sends the clock synchronization packet;

determine a forwarding delay of the clock synchronization packet in the wireless communication system based on the first timestamp and a second time at which the communication apparatus forwards the clock synchronization packet;

add the forwarding delay to a correction field in the clock synchronization packet; and

send, by the interface, the clock synchronization packet to the adjacent device at the second time at which the communication apparatus forwards the clock synchronization packet.

8. The communication apparatus according to claim 7 , wherein the non-transitory instructions that cause the at least one processor to receive the first clock source information comprises the at least one processor to:

receive, by the interface, first clock source announcement from the user plane network element, wherein the first clock source announcement comprises the first clock source information.

9. The communication apparatus according to claim 8 , wherein the non-transitory instructions that cause the at least one processor to send the first clock source information to the adjacent device comprises the at least one processor to:

send, by the interface, the first clock source announcement to the adjacent device.

10. The communication apparatus according to claim 7 , wherein the non-transitory instructions that cause the at least one processor to receive the first clock source information comprises the at least one processor to:

receive, by the interface, the first clock source information from a control plane network element, wherein the control plane network element corresponds to a network exposure function network element.

11. The communication apparatus according to claim 10 , wherein the non-transitory instructions that cause the at least one processor to send the first clock source information to the adjacent device comprises the at least one processor to:

generate a sixth clock source announcement based on the first clock source information, wherein the sixth clock source announcement comprises the first clock source information; and

send, by the interface, the sixth clock source announcement to the adjacent device.

12. The communication apparatus according to claim 10 , wherein the non-transitory instructions further cause the at least one processor to:

generate a clock synchronization packet in response to the clock source corresponding to the first clock source information is an optimal clock source; and

send, by the interface, the clock synchronization packet to the adjacent device.

13. A non-transitory computer-readable medium, wherein the non-transitory computer-readable storage medium comprises non-transitory instructions, and in response to the non-transitory instructions being executed by a processor, the processor is configured to perform at least one of:

receiving first clock source information, wherein the first clock source information corresponds to clock source information of a wireless communication system, wherein the first clock source information indicates that a fifth generation (5G) system clock is useable as a clock source;

sending the first clock source information to an adjacent device;

receiving a clock synchronization packet from a user plane network element, wherein the clock synchronization packet comprises a first timestamp, and the first timestamp represents a first time at which the user plane network element sends the clock synchronization packet;

determining a forwarding delay of the clock synchronization packet in the wireless communication system based on the first timestamp and a second time at which the terminal device forwards the clock synchronization packet; and

after adding the forwarding delay to a correction field in the clock synchronization packet, sending the clock synchronization packet to the adjacent device at the second time at which the terminal device forwards the clock synchronization packet.

14. The non-transitory computer-readable medium according to claim 13 , wherein

the processor configured to perform receiving the first clock source information comprises the processor being configured to perform:

receiving a first clock source announcement from the user plane network element, wherein the first clock source announcement comprises the first clock source information; and

the processor configured to perform sending the first clock source information to the adjacent device comprises the processor being configured to perform:

sending the first clock source announcement to the adjacent device.

15. The non-transitory computer-readable medium according to claim 13 , wherein the processor configured to perform receiving the first clock source information comprises the processor being configured to perform:

receiving the first clock source information from a control plane network element, wherein the control plane network element corresponds to a network exposure function network element.

16. The non-transitory computer-readable medium according to claim 15 , wherein the processor configured to perform sending the first clock source information to the adjacent device comprises the processor being configured to perform:

generating a sixth clock source announcement based on the first clock source information, wherein the sixth clock source announcement comprises the first clock source information; and

sending the sixth clock source announcement to the adjacent device.

17. The non-transitory computer-readable medium according to claim 15 , wherein the processor is further configured to perform at least one of:

generating a clock synchronization packet in response to the clock source corresponding to the first clock source information is an optimal clock source, and

sending the clock synchronization packet to the adjacent device.