| 摘要 |
Improved handling of multicast streams in digital networks. A switching device in a digital network such as a controller, bridge, or access point examines streams flowing through the device. The device identifies a multicast stream and assigns a stateful session to this stream. QoS marking may be applied to the stream. The device assigns a shaping policy to the stream, assigning it a default value in terms of bandwidth credits. This default value may be dependent on the stream type. The credits used by the stream are evaluated periodically. If the stream has exceeded the allocated bandwidth for the shaping policy, the number of credits are increased by a predetermined factor. If the stream has unused credits, the allocated number of credits are reduced by a predetermined factor. The increase and decrease factors may be tuned, for example, to provide a fast attack and a slow decay. The period used for stream evaluation may be adjusted. Increasing the period decreases the load on the device CPU; decreasing the period allows for better convergence at a cost of more load on the CPU. This approach allows the packets in the stream to be released at a constant rate and allows transmission of bursty traffic over networks on which congestion conditions can change rapidly such as wireless and vpn tunnels. In addition, the potential for downstream drops due to the lack of buffers in downstream switch/routers due to the burstiness is reduced. |
