US 6,584,111 B1 · ABR flow control using single bit congestion indication and wavelet transform filtering

Abstract

A flow control system and methodology controls and avoids congestion in an Asynchronous Transfer Mode (ATM) network. The congestion state of a network switch is determined based on incoming Available Bit Rate (ABR) traffic, Constant Bit Rate (CBR) traffic, and Variable Bit Rate (VBR) traffic. High-frequency fluctuations due to VBR traffic are filtered out of the CBR/VBR traffic to determine the underlying trend of network traffic. A filtering mechanism is based on wavelet transforms. The switch congestion state is determined based on the current ABR traffic, the filtered CBR/VBR traffic, and the current status of buffers in the switch. The congestion state can then be used to adjust the ABR rate according to a feedback scheme such as Explicit Forward Congestion Indication (EFCI).

Claims20

Dependent claims

A system for use in controlling congestion in a network, the network including a network switch having a first buffer for receiving packets of a first type into a first queue and a second buffer for receiving packets of a second type into a second queue having a queue length, the system comprising:

a first measurement module coupled to the first buffer for measuring an arrival rate of the packets of the first type, including
a sampler for sampling the arrivals of the first type packets;
and
a wavelet transform processor coupled to the sampler for determining an effective arrival rate of the first type packets in response to the sampled arrivals;
a second measurement module coupled to the second buffer for measuring an arrival rate of the packets of the second type;
and
a flow control module, coupled to the first and second measurement modules and the second buffer, for determining a congestion state of the switch based on the arrival rates of the first and second type packets and the queue length of the second queue.

4 more elements

Dependencies are inferred from the claim text.

ABR flow control using single bit congestion indication and wavelet transform filtering

Life of this patent

ABR flow control using single bit congestion indication and wavelet transform filtering

Life of this patent

Abstract

Claims20