Apparatus and method for congestion control in high speed networks
First Claim
1. A traffic congestion control apparatus for use in a network having a plurality of types of data traffic, said data traffic comprising high priority traffic and low priority traffic, said network having a plurality of links through which said data traffic flows, each of said links being susceptible to data traffic congestion, said apparatus comprising:
- a processor comprising a filter through which the data traffic flows;
a sampler which periodically measures a characteristic of said data traffic filtered by said filter, said measured characteristic indicating a present link capacity requirement of the filtered traffic;
a flow control system for adjusting a transmission flow rate of at least the low priority traffic of said data traffic; and
a comparator which compares the measured characteristic with a predetermined threshold, said comparator sending a first signal to said flow control system when the measured characteristic exceeds the predetermined threshold to thereby indicate link congestion, said comparator further sending a second signal to said flow control system when the measured characteristic is below the predetermined threshold to thereby indicate unused link capacity;
said flow control system reducing the transmission rate of the low priority traffic in response to receipt of the first signal and increasing the transmission rate of the low priority traffic in response to receipt of the second signal.
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Accused Products
Abstract
An adjustable bit rate (ABR) feedback control scheme is provided where the effects of multiloop delays and high priority traffic transmission are built into the control model. The data traffic is filtered by a low pass filter. Then, the low frequency bandwidth of the filtered traffic is measured and compared to a predetermined threshold. If the measured value exceeds the threshold, the ABR traffic flow is reduced. If the measured value is less than the threshold, the ABR traffic flow is increased. In addition, a General Prediction Control (GPC) method may be applied to the control model for optimal performance. An object of the invention is to minimize the unused link capacity subject to no congestion, where the ABR traffic is adapted to the low frequency variation of high priority traffic flow for high efficiency.
66 Citations
22 Claims
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1. A traffic congestion control apparatus for use in a network having a plurality of types of data traffic, said data traffic comprising high priority traffic and low priority traffic, said network having a plurality of links through which said data traffic flows, each of said links being susceptible to data traffic congestion, said apparatus comprising:
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a processor comprising a filter through which the data traffic flows; a sampler which periodically measures a characteristic of said data traffic filtered by said filter, said measured characteristic indicating a present link capacity requirement of the filtered traffic; a flow control system for adjusting a transmission flow rate of at least the low priority traffic of said data traffic; and a comparator which compares the measured characteristic with a predetermined threshold, said comparator sending a first signal to said flow control system when the measured characteristic exceeds the predetermined threshold to thereby indicate link congestion, said comparator further sending a second signal to said flow control system when the measured characteristic is below the predetermined threshold to thereby indicate unused link capacity; said flow control system reducing the transmission rate of the low priority traffic in response to receipt of the first signal and increasing the transmission rate of the low priority traffic in response to receipt of the second signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for controlling congestion in a network having data traffic comprising high priority traffic and low priority traffic, the low priority traffic being transmitted by a plurality of data inputs, said network comprising a plurality of links through which the data traffic flows, said method comprising:
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filtering the data traffic; and periodically repeating the following; sampling the filtered traffic to estimate a present link capacity required by the high priority traffic; determining the remaining link capacity; calculating a transmission rate for each data input to minimize an unused link capacity of each link subject to no congestion; and adjusting a transmission flow rate of each data input to match the calculated transmission rate. - View Dependent Claims (18, 19, 20, 21)
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22. A traffic congestion control apparatus for use in a network having a plurality of types of data traffic, said data traffic comprising high priority traffic and low priority traffic, said network having a plurality of links through which said data traffic flows, each of said links being susceptible to data traffic congestion, said apparatus comprising:
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filter means for filtering the data traffic; sampling means for sampling a characteristic of the data traffic filtered by the filtering means, the characteristic of the data traffic indicating a present link capacity requirement of the filtered traffic; and adjustment means for adjusting the transmission rate of the low priority traffic in response to the sampled characteristic.
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Specification