Zero-delay queuing method and system

A zero-delay queuing method, comprising the steps of:

• determining a traffic class for an input packet when the packet inputs into a class classifier of the CBQ scheduler;
• checking whether or not the determined class corresponds to a traffic class of a zero-delay queue;
• when a packet corresponds to a class set to perform zero-delay queuing, transferring the input packet to a zero-delay queue;
• said zero-delay queue comprising three phases which is a first zero-delay scheduling phase, a second zero-delay scheduling phase and a third zero-delay scheduling phase;
• when a packet corresponds to a class set to perform zero-delay queuing, performing said first zero-delay scheduling phase where the packet corresponding to the class set to perform zero-delay queuing is transferred to a strict priority transfer queue when a size of the packet does not exceed a Committed Rate (CR) value set for the class;
• when the size exceeds the CR value, performing in the second zero-delay scheduling phase where CR values set for classes corresponding to the zero-delay queue and general data queues are checked, the packet is transferred to the strict priority transfer queue while ensuring a Peak Rate (PR) value of the class when there is unreserved bandwidth;
• when there is no unreserved bandwidth, performing said third zero-delay scheduling phase where the packet is queued, and when it is determined from the CR values of the classes of packets queued in the respective general data queues that there is unused bandwidth, the unused bandwidth is further allocated to transfer the packet to the strict priority transfer queue;
• and
• forwarding the packet existing in the strict priority transfer queue prior to packets existing in general data transfer queues.

A zero-delay queuing system, comprising:

• a driver multiplexer (MUX);
• a Class-Based Queuing (CBQ) scheduler transferring a packet corresponding to a class set to perform zero-delay queuing to a zero-delay queue, performing zero-delay scheduling, and then transferring the packet to the driver multiplexer (MUX);
• said CBQ comprising a class classifier classifying a received packet according to a class, a zero-delay queue immediately transferring the packet corresponding to the class set to perform zero-delay queuing to the driver queue without queuing, and a plurality of general data queues transferring a queued packet to the driver queue in every operation period of the CBQ scheduler;
• and
• a plurality of driver queues forwarding the packet corresponding to the zero-delay queue prior to a general data packet, each of said driving queues comprising a strict priority transfer queue and a general data transfer queue.