Hierarchical Scheduling Tree for Multi-Granularity QoS Differentiation
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Solution Overview
Problem
Conventional packet scheduling mechanisms in data routing networks lack the flexibility to control Quality of Service (QoS) differentiation across multiple granularities, such as Internet service providers, business entities, and user groups, and fail to effectively manage traffic fairness and service differentiation beyond a single level of control.
Innovation Solution
A user-configurable hierarchical scheduling process, or scheduling tree, is employed to allocate data packets to queues in a network switching device, where each queue is assigned to a node in the tree, allowing for multiple levels of service category differentiation and fairness management by selecting winner nodes based on various attributes at each stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single-level scheduling process is used, then the device complexity is reduced, but the adaptability for QoS differentiation across multiple granularities deteriorates
Solution Approach 1:
The scheduling process is segmented into multiple hierarchical levels (root level for egress ports, intermediate levels for service categories, and leaf level for queues). Each level independently schedules packets within its granularity, enabling multi-dimensional QoS differentiation without requiring a monolithic complex scheduling structure.
Solution Approach 2:
The invention adds hierarchical dimensions to the scheduling structure by introducing intermediate service category levels between egress ports and queues. This transforms a flat single-level scheduling into a multi-dimensional hierarchical scheduling tree, enabling QoS control at multiple granularities (ISP, business entity, user group levels) simultaneously.
2Adaptability or versatility
If a hierarchical scheduling tree with multiple levels is implemented, then the adaptability for service differentiation is improved, but the device complexity increases
Solution Approach 1:
The hierarchical scheduling tree is implemented as a dynamic structure where intermediate levels can be configured and activated based on specific QoS requirements. The system can adaptively enable or disable certain hierarchical levels and service categories, allowing flexible service differentiation while avoiding unnecessary complexity when full hierarchy is not needed.
3Ease of operation
If user-configurable hierarchical scheduling is implemented, then the ease of operation for adapting QoS is improved, but the device complexity increases
Solution Approach 1:
The hierarchical scheduling tree structure serves multiple functions simultaneously: it provides QoS differentiation, traffic management, fairness control, and service categorization across multiple granularities. This universal structure eliminates the need for separate dedicated mechanisms for each function, reducing overall hardware and programming complexity while maintaining operational flexibility.
Data Source
AI summary
System and method of data routing according to a hierarchical scheduling process. Incoming data traffic is allocated to various queues of a buffer. A scheduling tree has a top level for queues, a bottom level for egress ports, and a plurality of intermediate levels corresponding to different granularities with respect to service categories. Each queue is assigned to a particular node in each intermediate level of the scheduling tree. The scheduling tree traverses through multiple scheduling stages from the bottom to the top level to select a winner node in each level based on a variety of fairness and differentiating variables. As a result, a queue associated with the winner nodes in various levels is selected and data from the queue is read out and sent to the selected egress port for transmission.