Network Device Egress Scheduling for Bandwidth Utilization
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Solution Overview
Problem
Existing local area communications networks face inefficiencies in resource utilization, particularly in bandwidth allocation, where allocated bandwidth that is not used by certain Quality of Service (QoS) states is 'wasted' and not utilized by other resources.
Innovation Solution
The implementation of a combination of minimum bandwidth guarantee/maximum bandwidth allowable shaping and weighted deficit round robin scheduling scheme to dynamically manage packet transmission and buffer resources, ensuring fair and full utilization of output bandwidth across different CoS queues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple QoS states are assigned with varying bandwidth allocation, then quality of service differentiation is improved, but bandwidth utilization efficiency deteriorates due to wasted unused allocated bandwidth
Solution Approach 1:
The patent implements dynamic bandwidth allocation where the network device continuously monitors buffer occupancy and adjusts packet scheduling in real-time. The egress module dynamically selects packets from different QoS queues based on current buffer conditions rather than following static allocation, allowing the system to adapt to changing traffic patterns and eliminate wasted bandwidth while maintaining QoS differentiation.
Solution Approach 2:
The system changes the parameter of bandwidth allocation from fixed to variable. By monitoring buffer occupancy levels and dynamically adjusting which QoS packets are transmitted, the system transforms the static bandwidth allocation parameter into a dynamic one that responds to actual network conditions, thereby improving overall utilization while preserving service differentiation.
2Reliability
If static bandwidth allocation is used for QoS states, then service differentiation is maintained, but resource utilization efficiency deteriorates due to wasted unused bandwidth
Solution Approach 1:
The patent implements a feedback mechanism where the egress module continuously monitors buffer occupancy levels and uses this information to adjust packet transmission decisions. This feedback loop allows the system to identify when allocated bandwidth for certain QoS states is unused and redirect that capacity to other queues, thereby eliminating wasted bandwidth while maintaining service differentiation through the monitoring and control logic.
Solution Approach 2:
The network device performs self-service by autonomously monitoring its own buffer conditions and making real-time scheduling decisions without external intervention. The egress module independently determines which packets to transmit based on current buffer occupancy, allowing the system to self-optimize bandwidth utilization while preserving QoS differentiation through its internal control logic.
3Productivity
If dynamic buffer management is implemented, then bandwidth utilization is improved, but system complexity increases due to additional scheduling mechanisms
Solution Approach 1:
The patent segments the packet transmission process into distinct phases: buffer monitoring, QoS classification, and selective transmission. By dividing the scheduling function into these manageable segments within the egress module, the system achieves dynamic bandwidth utilization through monitoring while keeping complexity manageable through functional separation and modular design.
4Reliability
If all output bandwidth is utilized by high priority packets, then quality of service for time-sensitive packets is improved, but fairness to other packets deteriorates
Solution Approach 1:
The system changes the transmission parameter from priority-based to condition-based. Instead of always transmitting high-priority packets when bandwidth is available, the egress module monitors buffer occupancy and only transmits high-priority packets when their buffers indicate actual need. This parameter change ensures QoS for time-sensitive packets while maintaining fairness, as bandwidth is allocated based on actual buffer conditions rather than static priority rules.
Data Source
AI summary
A network device for processing data includes at least one ingress module for performing switching functions on incoming data, a memory management unit for storing the incoming data and at least one egress module for transmitting the incoming data to at least one egress port. The at least one egress module includes an egress scheduling module and multiple queues per each of the at least one egress port. Each of the multiple queues serve data attributable to a class of service, and the egress scheduling module is configured to service a minimum bandwidth requirement for each of the multiple queues and then to service the multiple queues to allow for transmission of a maximum allowable bandwidth through a weighting of each of the multiple queues.