Patent ID: 8254403
Filing Date: 2012-08-28
Classification: H04L

Abstract:
1. A packet forwarding apparatus having plural ports that, upon receipt of a packet pre-classified with respect to a priority control, stores the packet in a buffer and then transmits it based on the priority control, the apparatus comprising: a first storage that, with respect to the packets currently stored in the buffer, stores, by the port and by the class, order information indicating the order in which the packet has been received and location information specifying at which location of the buffer the received packet is stored, in correspondence therewith; a transmitter that selects a predetermined port and class according to the priority control, reads out the packet stored foremost corresponding to the selected port and class out of the packets currently stored in the buffer from the buffer, using the order information and the location information stored in the first storage, and transmits it; a second storage that stores, by the port and by the class, a dedicated spending capacity indicating the capacity that only the packet of the class is permitted to spend out of the capacity of the buffer, and at least one of a current dedicated spending capacity indicating the capacity currently spent out of the dedicated spending capacity and a dedicated free capacity obtainable by subtracting the current dedicated spending capacity from the dedicated spending capacity, in correspondence therewith; a third storage that stores, by combination of classes between different ports and by combination of plural classes, a jointly owned spending capacity indicating the capacity that packets of the plural classes are permitted to jointly own and spend out of the capacity of the buffer, and at least one of a current jointly owed spending capacity indicating the capacity currently spent out of the jointly owned spending capacity and a jointly owned free capacity obtainable by subtracting the current jointly owned spending capacity from the jointly owned spending capacity, in correspondence therewith; and a processor that is operative to: identify the port and the class of the received packet; read out the dedicated free capacity corresponding to the port and the class identified from the second storage, determine whether there is the capacity for storing the received packet and, if it is determined that there is the capacity for storing the packet, store the packet in the buffer, treating the dedicated free capacity of the port and the class as having been spent; if it is determined that there is no capacity for storing the received packet, read out the jointly owned free capacity corresponding to the port and the class of the packet from the third storage, determine whether there is the capacity for storing the packet, and, if it is determined that there is the capacity for storing the packet, store the packet in the buffer, treating the jointly owned free capacity of the port and the class as having been spent; and if it is determined that there is no capacity for storing the received packet, discard the packet without storing it in the buffer, wherein the third storage stores a first positive value as the jointly owned spending capacity with respect to a combination of plural classes for the band warranty between different ports and stores a second positive value as the jointly owned spending capacity with respect to a combination of the class for the band warranty and the class for the best effort between different ports.