Bandwidth allocation method and apparatus

A token bucket limiter for congestion management over a network bottleneck, the token bucket limiter comprising a bucket for storing tokens for assignment to data packets, the bucket limiter comprising:

• an input unit for receiving packets of a given source with assigned priority levels;
• a rate limiter for inserting tokens into said bucket at a given rate;
• a thresholder for providing thresholds associated with priority levels, said thresholds defining numbers of tokens to be present before packets below said associated priority are eligible for token assignment, an overall number of said tokens defining a limiter bandwidth;
• and
• a token assigner for assigning tokens to arriving packets according to a respective priority level and associated threshold to allow passage of said packets;
• and
• wherein the token bucket limiter is located downstream of a congestion bottleneck having a bottleneck bandwidth, and wherein the limiter bandwidth is selected to be lower than said bottleneck bandwidth by a finite margin.

A method of congestion management for a plurality of sources sending data packets over a network bottleneck, the method comprising:

• setting an overall bandwidth over said bottleneck, said overall bandwidth being less by a finite margin than a maximum bandwidth physically allowed by said bottleneck;
• assigning said bandwidth between said sources as per source bandwidth allocations by:
• assigning priority levels to packets for each source;
• and
• for each source assigning highest priority packets in precedence per source;
• setting said finite margin in said overall bandwidth over said bottleneck to be a variable margin;
• and
• regulating said overall bandwidth assignment and variable margin from a point downstream of said bottleneck.