WRED Microburst Absorption via ABS Token Bucket
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Weighted Random Early Detection (WRED) approaches are inadequate in recognizing and managing microbursts, leading to unnecessary packet drops and performance degradation in networks, as they fail to differentiate between microbursts and sustained bursts and do not efficiently utilize available buffer resources.
Innovation Solution
Implementing an Acceptable Burst Size (ABS) token bucket mechanism within the WRED algorithm that delays packet drops until the ABS token bucket is empty, allowing for the absorption of microbursts by adjusting the token bucket size based on packet enqueue and dequeue rates, thereby enabling efficient handling of bursty traffic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional WRED is used to avoid congestion, then packet drops are reduced during sustained traffic, but microbursts are incorrectly identified as congestion and cause unnecessary packet drops
Solution Approach 1:
The patent segments the traffic analysis into two distinct components: sustained traffic monitoring using traditional WRED and burst traffic monitoring using the ABS token bucket. This segmentation allows each mechanism to specialize in detecting its target traffic pattern, preventing microbursts from being misidentified as congestion while maintaining WRED's effectiveness for sustained traffic.
Solution Approach 2:
The ABS token bucket acts as an intermediary mechanism that sits between the ingress port and the WRED congestion avoidance algorithm. It monitors traffic patterns and controls when WRED should be enforced, preventing microbursts from triggering unnecessary packet drops while allowing WRED to function properly for actual congestion conditions.
2Reliability
If packet buffers are increased to absorb microbursts, then microburst absorption capability is improved, but buffer resources are wasted on sustained bursts that should be dropped
Solution Approach 1:
The ABS token bucket size is dynamically adjusted based on the difference between ingress and egress rates. When microbursts occur (high ingress, low egress), the token bucket absorbs the excess packets. When sustained bursts occur (both rates high and equal), the buffer utilization is optimized by allowing drops. This dynamic behavior ensures buffer resources are used efficiently for their intended purpose.
Solution Approach 2:
The patent changes the operational parameters of the buffer by introducing the ABS token bucket mechanism with a dynamically calculated size. The token bucket size is determined by the formula ABS = (Ingress Rate - Egress Rate) × Burst Duration, allowing the system to adapt buffer behavior to current traffic conditions rather than using a fixed buffer size.
3Reliability
If WRED enforcement is delayed to absorb microbursts, then microburst packet loss is reduced, but congestion avoidance response time is increased
Solution Approach 1:
The system uses feedback from the ABS token bucket monitoring mechanism to control WRED enforcement. The token bucket continuously monitors traffic patterns and provides feedback on whether current traffic is a microburst or sustained burst, enabling the system to respond appropriately without unnecessary delays. This feedback mechanism ensures rapid response to actual congestion while protecting microbursts.
Data Source
AI summary
A packet queueing system includes an ingress port configured to receive packets; queueing logic communicatively coupled to one or more egress queues for transmission via an egress port, wherein the queueing logic is configured to maintain an Acceptable Burst Size (ABS) token bucket which is set to enable absorption of microbursts, and implement a congestion avoidance algorithm to one of randomly drop packets and queue packets, wherein the congestion avoidance algorithm only performs the randomly drop packets responsive to the ABS token bucket being empty.