US 6,636,524 B1 · Method and system for handling the output queuing of received packets in a switching hub in a packet-switching network

Abstract

A method and system is provided for use on a switching hub in a packet-switching network for handling the output queuing of received packets in the switching hub to be more efficient and cost-effective. This method and system is characterized in the provision of a broadcast output queue in addition to the output queues at the ports of the switching hub, with the broadcast output queue being exclusively used for sequencing broadcast packets and the output queues being used exclusively for sequencing unicast packets. When a broadcast packet is received, the method and system assigns a free-list link node to the broadcast output queue, but not to the output queues, and meanwhile adds one to the broadcast count in each of the last link node in each of the output queues. When a certain port completes the outputting of all associated unicast packets, it is checked whether the broadcast count in the last link node in each output queue is zero or nonzero; if nonzero, the switching hub then outputs every broadcast packet indicated by the broadcast count. The disclosed method and system not only allows a reduced number of memory accesses as compared to the prior art but also requires a low memory capacity to implement, and therefore is more efficient in operation and more cost-effective to implement than the prior art.

Claims15

Dependent claims

A method for use on a switching hub in a packet-switching network for the purpose of handling the output queuing of received packets in the switching hub, the switching hub having a plurality of ports, with each port being associated with an output queue, the method comprising the steps of:

providing a broadcast output queue in addition to the output queues at the ports of the switching hub;
in response to a received packet, checking whether the received packet is a unicast packet or a broadcast packet;
if unicast packet, assigning a free-list link node to the output queue at the destination port of the received unicast packet, the link node containing a broadcast count indicative of the number of currently received broadcast packets in the switching hub;
otherwise,
if a broadcast packet, assigning a free-list link node to the broadcast output queue and meanwhile adding one to the broadcast count in each of the last link node in each of the output queues at the ports of the switching hub;
checking whether the broadcast count in each of the last link node in each of the output queues at the ports of the switching hub;
if zero, outputting the unicast packet pointed by the link node;
otherwise,
if nonzero, outputting the broadcast packet indicated by the broadcast count.

6 more elements

A system for use on a switching hub in a packet-switching network for the purpose of handling the output queuing of received packets in the switching hub, the switching hub having a plurality of ports, with each port being associated with an output queue;

the system comprising:
a first memory unit for storing a forward table and a free-list link node set, the forward table being used to register the source address and destination port number of each received packet, and the free-list link node set being used to contain available link nodes of free lists in the switching hub;
a second memory unit including a plurality of packet buffers for temporary storage of received packets;
a plurality of output queues, each being associated with one of the ports of the switching hub and being used for the sequencing of received packets that are awaiting for outputting from designated ports;
a broadcast output queue used for the sequencing of received broadcast packets that are awaiting for outputting from the switching hub;
and
a switching control unit for controlling the access operations to the first and second memory units and the enqueuing and dequeuing of the output queues and the broadcast output queue;
the switching control unit operating in such a manner that when a packet is received, the switching control unit checks whether the received packet is a unicast packet or a broadcast packet;
if a unicast packet, the switching control unit retrieves a free-list link node from the first memory unit and then assigns the retrieved link node to the output queue at the destination port of the received unicast packet, the link node further containing a broadcast count indicative of the number of currently received broadcast packets in the switching hub;
otherwise, if a broadcast packet, the switching control unit retrieves a free-list link node from the first memory unit and assigns the retrieved link node to the broadcast output queue and meanwhile adding one to the broadcast count in each of the last link node in each of the output queues.

7 more elements

Dependencies are inferred from the claim text.

Method and system for handling the output queuing of received packets in a switching hub in a packet-switching network

Life of this patent

Method and system for handling the output queuing of received packets in a switching hub in a packet-switching network

Life of this patent

Abstract

Claims15