Transfer device and frame transfer method

A frame transfer method comprising:

• calculating a first code that is a frame check sequence code of a received frame;
• comparing the first code with a second code that is a frame check sequence code stored in the received frame, and outputting a first comparison result indicating a match or no match between two codes compared with each other;
• comparing the first code with a third code obtained by inverting each bit of the second code, and outputting a second comparison result indicating a match or no match between two codes compared with each other;
• determining an error state of the received frame on a basis of the first comparison result and the second comparison result;
• and
• updating, if the second comparison result indicates no match, the second code with a fourth code obtained by inverting each bit of the first code at a time when the received frame is transferred to a subsequent device.

A transfer device comprising:

• a processor, and
• a memory to store a program which, when executed by the processor, performs processes of calculating a first code that is a frame check sequence code of a received frame;
• comparing the first code with a second code that is a frame check sequence code stored in the received frame, and outputting a first comparison result indicating a match or no match between two codes compared with each other;
• comparing the first code with a third code obtained by inverting each bit of the second code, and outputting a second comparison result indicating a match or no match between two codes compared with each other;
• determining an error state of the received frame on a basis of the first comparison result and the second comparison result;
• and
• updating, if the second comparison result indicates no match, the second code with a fourth code obtained by inverting each bit of the first code at a time when the received frame is transferred to a subsequent device.