Packet transmission method, device, and communications system

1. A communications system comprising:

a first forwarding plane apparatus configured to:

receive a media access control (MAC) address request broadcast by a base station, wherein the MAC address request includes a target Internet Protocol (IP) address and is used to request a MAC address corresponding to the target IP address;

forward the MAC address request; and

omit saving a first correspondence between the target IP address and the MAC address;

a second forwarding plane apparatus; and

a serving gateway (SGW) control plane apparatus configured to:

receive the MAC address request forwarded by the first forwarding plane apparatus;

acquire the MAC address according to the first correspondence and the target IP address; and

send a MAC address request response that includes the MAC address, wherein the first forwarding plane apparatus is further configured to:

receive the MAC address request response;

forward the MAC address request response to the base station; and

send a second forwarding instruction to the second forwarding plane apparatus to instruct the second forwarding plane apparatus to discard a data packet whose target MAC address is the MAC address.

2. The communications system of claim 1 , wherein the SGW control plane apparatus is further configured to acquire the first correspondence from a configuration database.

3. The communications system of claim 1 , wherein the SGW control plane apparatus is further configured to send a first forwarding instruction to the first forwarding plane apparatus, wherein the first forwarding instruction is used to instruct the first forwarding plane apparatus to forward the MAC address request response to the base station, and wherein the first forwarding plane apparatus is further configured to send the MAC address request response to the base station according to the first forwarding instruction.

4. The communications system of claim 1 , wherein the communications system further comprises a network management apparatus, wherein the first forwarding plane apparatus is configured to forward the MAC address request to the network management apparatus, and wherein the network management apparatus is configured to:

receive the MAC address request forwarded by the first forwarding plane apparatus; and

send the MAC address request to the SGW control plane apparatus.

5. The communications system of claim 4 , wherein the communications system further comprises a second control plane apparatus, and wherein the network management apparatus is further configured to broadcast the MAC address request to the SGW control plane apparatus and to the second control plane apparatus.

6. The communications system of claim 4 , wherein the network management apparatus is further configured to send the MAC address request to the SGW control plane apparatus according to the target IP address and a second correspondence between the target IP address and the SGW control plane apparatus.

7. The communications system of claim 6 , wherein the network management apparatus is further configured to acquire the second correspondence from a configuration database.

8. The communications system of claim 4 , wherein the network management apparatus is further configured to:

receive the MAC address request response from the SGW control plane apparatus; and

send the MAC address request response to the first forwarding plane apparatus.

9. A forwarding plane apparatus comprising:

a first receiver configured to receive a media access control (MAC) address request broadcast by a base station, wherein the MAC address request includes a target Internet Protocol (IP) address and is used to request a MAC address corresponding to the target IP address; and

a first transmitter coupled to the first receiver and configured to:

forward the MAC address request to a serving gateway (SGW) control plane apparatus when the forwarding plane apparatus does not save a first correspondence between the target IP address and the MAC address so that the SGW control plane apparatus acquires the MAC address according to the first correspondence and the target IP address and sends a MAC address request response to the forwarding plane apparatus, wherein the MAC address request response includes the MAC address,

wherein the first receiver is further configured to receive the MAC address request response; and

wherein the first transmitter is further configured to forward the MAC address request response to the base station; and

a second receiver configured to receive a second forwarding instruction from the SGW control plane apparatus; and

a second transmitter coupled to the second receiver and configured to, based on the second forwarding instruction, discard a data packet whose target MAC address is the MAC address.

10. The forwarding plane apparatus of claim 9 , wherein the first receiver is further configured to receive a first forwarding instruction sent by the SGW control plane apparatus, wherein the first forwarding instruction is used to instruct the forwarding plane apparatus to forward the MAC address request response to the base station, and wherein the first transmitter is further configured to send the MAC address request response to the base station according to the first forwarding instruction.

11. The forwarding plane apparatus of claim 9 , wherein the first transmitter is further configured to forward the MAC address request to a network management apparatus for forwarding the MAC address request to the SGW control plane apparatus.

12. The forwarding plane apparatus of claim 9 , wherein the first receiver is further configured to receive the MAC address request response forwarded by the SGW control plane apparatus by using a network management apparatus.

13. A serving gateway (SGW) control plane apparatus comprising:

a receiver configured to receive a media access control (MAC) address request that includes a target Internet Protocol (IP) address used to request a MAC address corresponding to the target IP address;

a processor coupled to the receiver and configured to acquire the MAC address of the target IP address and a first correspondence between the target IP address and the MAC address; and

a transmitter coupled to the processor and configured to:

send a MAC address request response to a first forwarding plane apparatus for forwarding the MAC address request response to a base station, wherein the MAC address request response includes the MAC address; and

send a second forwarding instruction to a second forwarding plane apparatus for instructing the second forwarding plane apparatus to discard a data packet whose target MAC address is the MAC address.

14. The SGW control plane apparatus of claim 13 , wherein the SGW control plane apparatus is configured to save the first correspondence.

15. The SGW control plane apparatus of claim 13 , wherein the SGW control plan apparatus is configured to acquire the first correspondence from a configuration database.

16. The SGW control plane apparatus of claim 13 , wherein the transmitter is further configured to send a first forwarding instruction to the first forwarding plane apparatus, and wherein the first forwarding instruction is used to instruct the first forwarding plane apparatus to forward the MAC address request response to the base station.

17. The SGW control plane apparatus of claim 13 , wherein the receiver is further configured to receive the MAC address request forwarded by the first forwarding plane apparatus by using a network management apparatus.

18. The SGW control plane apparatus of claim 13 , wherein the transmitter is further configured to forward the MAC address request response to the first forwarding plane apparatus by using a network management apparatus for forwarding the MAC address request response to the base station.