Communications method and apparatus

1. A communications, method comprising:

receiving a first indication from a mobility management entity, wherein the first indication is to retain first data for a power-saving user equipment device, and wherein the first data is downlink data of the power-saving user equipment device; and

determining, according to the first indication, a period for retaining the first data.

2. The communications method according to claim 1 , wherein the first indication comprises a suggested waiting time period to retain the first data.

3. The communications method according to claim 1 , further comprising retaining the first data according to the period.

4. The communications method according to claim 1 , further comprising:

receiving, from the mobility management entity, a second indication comprising an instruction to normally transmit and receive the first data, wherein the second indication is based on a state of the power-saving user equipment device after the state changes; and

normally transmitting and receiving the first data according to the second indication.

5. The communications method according to claim 1 , wherein the first indication comprises a paging delaying indicator indicating that the mobility management entity needs to delay paging the power-saving user equipment device.

6. The communications method according to claim 1 , wherein the communications method is performed by a data forwarding entity.

7. The communications method according to claim 1 , wherein before receiving the first indication, the communications method further comprises:

making, according to information of the power-saving user equipment device, a determination that the power-saving user equipment device is a power-saving device;

generating the first indication in response to the determination; and

sending the first indication.

8. The communications method according to claim 7 , further comprising:

receiving a non-access stratum (NAS) message from the power-saving user equipment device; and

acquiring the information according to the NAS message.

9. A communications, apparatus comprising:

a memory configured to store program codes;

a receiver configured to receive a first indication from a mobility management entity, wherein the first indication is to retain first data for a power-saving user equipment device, and wherein the first data is downlink data of the power-saving user equipment device; and

at least one processor coupled to the memory and receiver and configured to execute the program codes to cause the communications apparatus to determine a period for retaining the first data according to the first indication.

10. The communications apparatus according to claim 9 , wherein the at least one processor is further configured to execute the program codes to cause the communications apparatus to retain the first data according to the period.

11. The communications apparatus according to claim 9 , wherein the first indication comprises a suggested waiting time period to retain the first data.

12. The communications apparatus according to claim 9 , wherein the receiver is further configured to receive, from the mobility management entity, a second indication comprising an instruction to normally transmit and receive the first data, wherein the second indication is based on a state of the power-saving user equipment device after the state changes, and wherein the at least one processor is further configured to execute the program codes to cause the communications apparatus to normally transmit and receive the first data according to the second indication.

13. The communications apparatus according to claim 9 , wherein the first indication comprises a paging delaying indicator indicating that the mobility management entity needs to delay paging the power-saving user equipment device.

14. The communications apparatus according to claim 9 , wherein the communications apparatus is a data forwarding entity.

15. A communications, system comprising:

a mobility management entity configured to:

determine, according to information of a user equipment device, that the user equipment device is a power-saving user equipment device;

generate a first indication to retain first data for the power-saving user equipment device, wherein the first data is downlink data of the power-saving user equipment device and

send the first indication; and

a data forwarding entity configured to:

receive the first indication from the mobility management entity; and

determine a period for retaining the first data according to the first indication.

16. The communications system according to claim 15 , wherein the first indication comprises a suggested waiting time period to retain the first data.

17. The communications system according to claim 15 , wherein the data forwarding entity is further configured to retain the first data according to the period.

18. The communications system according to claim 15 , wherein the data forwarding entity is further configured to:

receive, from the mobility management entity, a second indication comprising an instruction to normally transmit and receive the first data, wherein the second indication is based on a state of the user equipment device after the state changes; and

normally transmit and receive the first data according to the second indication.

19. The communications system according to claim 15 , wherein the first indication comprises a paging delaying indicator indicating that the mobility management entity needs to delay paging the user equipment device.

20. The communications system according to claim 15 , wherein the mobility management entity is further configured to:

receive a non-access stratum (NAS) message from the user equipment device; and

acquire the information according to the NAS message.

21. A communications method comprising:

determining, by a mobility management entity and according to information of a user equipment device, that the user equipment device is a power-saving user equipment device;

generating, by the mobility management entity, a first indication for a data forwarding entity to retain first data for the power-saving user equipment device, wherein the first data is downlink data of the power-saving user equipment device;

sending, by the mobility management entity and to the data forwarding entity, the first indication;

receiving, by the data forwarding entity and from the mobility management entity, the first indication; and

determining, by the data forwarding entity, a period for retaining the first data according to the first indication.

22. The communications method according to claim 21 , wherein the first indication comprises a suggested waiting time period to retain the first data.

23. The communications method according to claim 21 , further comprising retaining, by the data forwarding entity, the first data according to the period.

24. The communications method according to claim 21 , further comprising:

receiving, by the data forwarding entity and from the mobility management entity, a second indication comprising an instruction to normally transmit and receive the first data, wherein the second indication is based on a state of the user equipment device after a change of the state; and

normally transmitting and receiving, by the data forwarding entity, the first data according to the second indication.

25. The communications method according to claim 21 , wherein the first indication comprises a paging delaying indicator indicating that the mobility management entity needs to delay paging the user equipment device.

26. The communications method according to claim 21 , further comprising:

receiving, by the mobility management entity and from the user equipment device, a non-access stratum (NAS) message; and

acquiring, by the mobility management entity, the information according to the NAS message.