Responsive to detecting that bandwidth consumption of a packet flow has exceeded a threshold, packet forwarding treatment is changed in accordance with at least one class of packet flow from a first packet forwarding treatment to a second packet forwarding treatment.

Dynamic Assignment of Traffic Classes to a Priority Queue in a Packet Forwarding Device
Traffic Classes to a Priority Queue in a Packet Forwarding Device

Traffic Classes to a Priority Queue in a Packet Forwarding Device


The present invention relates to telecommunications, and more particularly to the dynamic assignment of traffic classes to queues having different priority levels.

  • The flow of packets through packet-switched networks is controlled by switches and routers that forward packets based on destination information included in the packets themselves. A typical switch or router includes several input/output (I/O) modules connected to a switching fabric, such as a crossbar or shared memory switch. In some switches and routers, the switching fabric is operated at a higher frequency than the transmission frequency of the I/O modules. The switching fabric may deliver packets to an I/O module faster than the I/O module can output them to the network transmission medium. In these devices, packets are usually queued in the I/O module to await transmission.

  • One problem that may occur when packets are queued in the I/O module or elsewhere in a switch or router is that the queuing delay per packet varies depending on the amount of traffic being handled by the switch. Variable queuing delays tend to degrade data streams produced by real-time sampling (e.g., audio and video) because the original time delays between successive packets in the stream convey the sampling interval and are therefore needed to reproduce the source information faithfully. Another problem that results from queuing packets in a switch or router is that data from a relatively important source, such as a shared server, may be impeded by data from less important sources, resulting in bottlenecks.

  • A method and apparatus for dynamic assignment of classes of traffic to a priority queue are disclosed. Bandwidth consumption by one or more types of packet traffic received in a packet forwarding device is monitored. The queue assignment of at least one type of packet traffic is automatically changed from a queue having a first priority to a queue having a second priority if the bandwidth consumption exceeds the threshold.

  • Other features and advantages of the invention will be apparent from the accompanying drawings and the detailed description below.