Switching device, method and storage medium

1. A switching device including a plurality of communication ports, comprising:

a receiving unit configured to receive a frame from a first external communication device connected to a first communication port of the communication ports;

a first database and a second database configured to store destination determination information used to determine a second communication port of the communication ports to which a second external communication device serving as a destination of the received frame, is connected; and

a determination unit configured to determine the second communication port by accessing destination determination information stored in the first database based on header information added to a first frame which is to be forwarded with low delay when the received frame is the first frame, and determine the second communication port by accessing destination determination information stored in the second database based on header information added to a second frame which differs from the first frame when the received frame is the second frame, wherein:

the first database is accessible to the destination determination information at a higher speed than the second database;

the determination unit is configured to cache first destination determination information stored in the first database and second destination determination information stored in the second database, and determine the second communication port based on the cached first and second destination determination information;

the first destination determination information stored in the first database and the cached first destination determination information are not synchronized with each other upon receipt of the first frame; and

the second destination determination information stored in the second database and the cached second destination determination information are synchronized with each other upon receipt of the second frame.

2. The switching device of claim 1 , further comprising:

a first reception queue configured to store the first frame; and

a second reception queue configured to store the second frame,

wherein:

the determination unit includes a first determination unit and a second determination unit;

the first determination unit is configured to determine the second communication port based on header information added to the first frame extracted from the first reception queue; and

the second determination unit is configured to determine the second communication port based on header information added to the second frame extracted from the second reception queue.

3. The switching device of claim 2 , further comprising a third database configured to store attribute information indicating that the first reception queue is a reception queue for the first frame and the second reception queue is a reception queue for the second frame,

wherein:

the first frame is extracted from the first reception queue distinguished based on the attribute information; and

the second frame is extracted from the second reception queue distinguished based on the attribute information.

4. The switching device of claim 1 , further comprising a reception queue configured to store the received frame,

wherein the determination unit is configured to determine whether a frame extracted from the reception queue is the first frame or the second frame based on header information of the frame.

5. The switching device of claim 1 , wherein:

the destination determination information stored in the first database is not updated upon receipt of the first frame; and

the destination determination information stored in the second database is updated upon receipt of the second frame.

6. The switching device of claim 1 , wherein:

the first database is configured to manage the destination determination information using a content addressable memory (CAM); and

the second database is configured to manage the destination determination information using a hash table which holds a hash value calculated from the destination determination information.

7. The switching device of claim 1 , wherein:

the first frame includes an Express frame of IEEE 802.1 Qbu/IEEE 802.3 br; and

the second frame includes a Preemptable frame of IEEE 802.1 Qbu/IEEE 802.3 br.

8. The switching device of claim 1 , wherein the second database has a capacity that is larger than a capacity of the first database.

9. A method executed by a switching device including a plurality of communication ports, comprising:

receiving a frame from a first external communication device connected to a first communication port of the communication ports; and

determining a second communication port to which a second external communication device serving as a destination of the received frame is connected, by accessing destination determination information stored in a first database based on header information added to a first frame which is to be forwarded with low delay when the received frame is the first frame, and determining the second communication port by accessing destination determination information stored in a second database based on header information added to a second frame which differs from the first frame when the received frame is the second frame, wherein:

the first database is accessible to the destination determination information at a higher speed than the second database;

the determining comprises caching first destination determination information stored in the first database and second destination determination information stored in the second database, and determining the second communication port based on the cached first and second destination determination information;

the first destination determination information stored in the first database and the cached first destination determination information are not synchronized with each other upon receipt of the first frame; and

the second destination determination information stored in the second database and the cached second destination determination information are synchronized with each other upon receipt of the second frame.

10. The method of claim 9 , wherein:

the switching device includes a first reception queue configured to store the first frame and a second reception queue configured to store the second frame; and

the determining includes:

determining the second communication port based on header information added to the first frame extracted from the first reception queue; and

determining the second communication port based on header information added to the second frame extracted from the second reception queue.

11. The method of claim 10 , wherein:

the switching device further includes a third database configured to store attribute information indicating that the first reception queue is a reception queue for the first frame and the second reception queue is a reception queue for the second frame;

the first frame is extracted from the first reception queue distinguished based on the attribute information; and

the second frame is extracted from the second reception queue distinguished based on the attribute information.

12. The method of claim 9 , wherein:

the switching device further includes a reception queue configured to store the received frame; and

the determining includes determining whether a frame extracted from the reception queue is the first frame or the second frame based on header information of the frame.

13. The method of claim 9 , wherein:

the destination determination information stored in the first database is not updated upon receipt of the first frame; and

the destination determination information stored in the second database is updated upon receipt of the second frame.

14. A non-transitory computer-readable storage medium having stored thereon a program executed by a computer of a switching device including a plurality of communication ports, the program comprising instructions capable of causing the computer to execute functions of:

receiving a frame from a first external communication device connected to a first communication port of the communication ports; and

determining a second communication port to which a second external communication device serving as a destination of the received frame is connected, by accessing destination determination information stored in a first database based on header information added to a first frame which is to be forwarded with low delay when the received frame is the first frame, and determining the second communication port by accessing destination determination information stored in a second database based on header information added to a second frame which differs from the first frame when the received frame is the second frame,

wherein:

the first database is accessible to the destination determination information at a higher speed than the second database;

the determining comprises caching first destination determination information stored in the first database and second destination determination information stored in the second database, and determining the second communication port based on the cached first and second destination determination information;

the first destination determination information stored in the first database and the cached first destination determination information are not synchronized with each other upon receipt of the first frame; and

the second destination determination information stored in the second database and the cached second destination determination information are synchronized with each other upon receipt of the second frame.