SDN-based ARP implementation method and apparatus

1. A software defined networking (SDN) based Address Resolution Protocol (ARP) implementation method, comprising:

receiving, by a controller, a first ARP request from a first switch;

determining, by the controller, whether an ARP entry corresponding to the first ARP request does not exist locally;

when determining the ARP entry corresponding to the first ARP request does not exist locally, sending, by the controller, only to the first switch, a first instruction configured to instruct the first switch to flood the first ARP request;

if determining, by the controller, that the ARP entry corresponding to the first ARP request exists locally, determining, by the controller, a destination switch based on the ARP entry, and sending the first ARP request to the destination switch;

after sending the first ARP request to the destination switch, if an ARP response returned by the destination switch is not received within a specified duration, deleting the locally stored ARP entry corresponding to the first ARP request, and sending, to the first switch, a second instruction configured to instruct the first switch to flood the first ARP request,

wherein the second instruction is configured to instruct the first switch to send the first ARP request to both a switch that is adjacent to the first switch and a host that is connected to the first switch.

2. The method according to claim 1 , wherein the first instruction is configured to instruct the first switch to send the first ARP request to both a switch that is adjacent to the first switch and a host that is connected to the first switch.

3. The method according to claim 1 , before receiving the first ARP request, further comprising:

configuring, by the controller, a preset flow table rule for the first switch,

wherein the flow table rule specifies that when a switch receives an ARP request from an adjacent switch, the switch floods the ARP request.

4. The method according to claim 1 , after sending the first instruction, further comprising:

receiving a first ARP response, forwarding the first ARP response to the first switch, and locally storing an ARP entry in the first ARP response.

5. The method according to claim 1 , after sending the first ARP request to the destination switch, further comprising:

if a second ARP response returned by the destination switch is received, forwarding the second ARP response to the first switch.

6. The method according to claim 5 , after sending the second ARP response, further comprising:

when receiving a third ARP response from a second switch, locally storing an ARP entry included in the third ARP response; and

forwarding the third ARP response to the first switch.

7. A software defined networking (SDN)-based Address Resolution Protocol (ARP) implementation apparatus, comprising a transceiver, a processor, a memory, and a bus, wherein the transceiver, the processor, and the memory are connected to the bus, the memory is configured to store a set of machine readable instructions, and the processor is configured to invoke the set of machine readable instructions stored in the memory and cause the apparatus to perform a method comprising:

receiving a first ARP request from a first switch;

determining whether an ARP entry corresponding to the first ARP request does not exist locally;

sending, when it is determined that the ARP entry corresponding to the first ARP request does not exist locally, only to the first switch, a first instruction configured to instruct the first switch to flood the first ARP request;

if determining that the ARP entry corresponding to the first ARP request exists locally, determining a destination switch based on the ARP entry, and sending the first ARP request to the destination switch; and

after sending the first ARP request to the destination switch, if an ARP response returned by the destination switch is not received within a specified duration, deleting the locally stored ARP entry corresponding to the first ARP request, and sending, to the first switch, a second instruction configured to instruct the first switch to flood the first ARP request,

wherein the second instruction is configured to instruct the first switch to send the first ARP request to both a switch that is adjacent to the first switch and a host that is connected to the first switch.

8. The apparatus according to claim 7 , wherein the first instruction is configured to instruct the first switch to send the first ARP request to both a switch that is adjacent to the first switch and a host that is connected to the first switch.

9. The apparatus according to claim 7 , wherein the processor is configured to cause the apparatus to perform the method further comprising:

before receiving the first ARP request, configuring a preset flow table rule for the first switch, wherein

the flow table rule specifies that when a switch receives an ARP request from an adjacent switch, the switch floods the ARP request.

10. The apparatus according to claim 7 , wherein the processor is configured to cause the apparatus to perform the method further comprising:

after sending the first instruction to the first switch, receiving a first ARP response;

sending, to the first switch, the first ARP response; and

locally storing an ARP entry in the first ARP response.

11. The apparatus according to claim 7 , wherein the processor is configured to cause the apparatus—to perform the method further comprising:

after sending the second instruction to the first switch, when receiving a third ARP response from a second switch, locally storing an ARP entry comprised in the third ARP response; and

sending the third ARP response to the first switch.

12. The apparatus according to claim 7 , wherein the apparatus is a controller.

13. A non-transitory computer-readable medium for storing machine readable instructions executable by one or more processors, wherein the machine readable instructions instruct the one or more processors to perform operations of:

receiving a first ARP request from a first switch;

determining whether an ARP entry corresponding to the first ARP request does not exist locally;

sending, when it is determined that the ARP entry corresponding to the first ARP request does not exist locally, only to the first switch, a first instruction configured to instruct the first switch to flood the first ARP request;

if determining that the ARP entry corresponding to the first ARP request exists locally, determining a destination switch based on the ARP entry, and sending the first ARP request to the destination switch; and

after sending the first ARP request to the destination switch, if an ARP response returned by the destination switch is not received within a specified duration, deleting the locally stored ARP entry corresponding to the first ARP request, and sending, to the first switch, a second instruction configured to instruct the first switch to flood the first ARP request, wherein the second instruction is configured to instruct the first switch to send the first ARP request to both a switch that is adjacent to the first switch and a host that is connected to the first switch.