NETWORK COMMUNICATION DEVICE AND TRANSFER FRAME PRIORITY BAND RESTRICTION METHOD

摘要

Provided is a network communication device with which when a transfer or disposal process is implemented in which a priority is assigned to each transfer frame in a network communication apparatus a band restriction is carried out to avoid congestion at a transfer destination device. Specifically a bucket is disposed for each priority and a token quantity is supplemented according to the priority. Before evaluating the buckets a shared bucket is disposed. For each given period all of the tokens which are present in the buckets which are disposed for each priority are assigned to the shared bucket. Overflow tokens exceeding the depth of the shared bucket are disposed of. So long as the tokens are present in the shared bucket all frames are evaluated equally and transferred regardless of frame priority. If no tokens are present in the shared bucket a switch is made to a priority restriction and each priority bucket is evaluated. The bucket which corresponds to the priority of the frame is verified and if the token is present a frame transfer process is carried out. If the token is not present a frame disposal process is carried out.