Prioritized Lookup Table for Packet Processing
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Solution Overview
Problem
Existing methods for packet processing using Content-Addressable Memory (CAM) or hash functions are costly and complex, making them unsuitable for small-size lookup tables, especially in cost-sensitive market applications where they do not meet product requirements.
Innovation Solution
A method and system for hardware table lookup that uses a prioritized, multi-condition, and wildcard-inclusive lookup table, where each entry includes conditions and a result/action indicator, sorted in priority order, with bit map arrays processed using logic OR and AND procedures to apply the highest priority rule to packets, reducing the need for CAM or hash solutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If CAM or hash function is used for lookup table implementation, then searching speed is improved, but hardware cost and circuit complexity increase
Solution Approach 1:
The patent segments the lookup table into multiple priority levels and uses bitwise operations to process different condition combinations separately. This segmentation allows the system to avoid complex CAM circuits while maintaining high searching speed through parallel bitwise processing of segmented data.
Solution Approach 2:
The patent replaces the mechanical/electrical CAM comparison mechanism with software-based bitwise logic operations. Instead of using specialized CAM hardware for direct comparison, the system uses standard processors with bitwise AND, OR, and NOT operations to achieve the same lookup function with reduced hardware complexity.
2Adaptability or versatility
If CAM or hash solution is used, then lookup functionality is improved, but product cost increases making it unsuitable for cost-sensitive markets
Solution Approach 1:
The patent creates a universal lookup mechanism that can handle multiple condition types (exact match, wildcard, priority-based) using the same bitwise operation framework. This multi-functional approach eliminates the need for specialized hardware for different lookup scenarios, reducing overall product cost while maintaining versatile lookup functionality.
Solution Approach 2:
The patent uses standard, inexpensive processor instructions and memory structures instead of expensive dedicated CAM hardware. By leveraging readily available computational resources with bitwise operations, the system achieves lookup functionality at a fraction of the cost of traditional CAM implementations.
3Measurement precision
If prioritized multi-condition matching is implemented, then packet processing accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent performs preliminary organization of lookup table entries by priority level and pre-computes bitwise masks for different condition combinations. This preliminary structuring allows the processing system to simply apply pre-prepared bitwise operations in priority order, achieving high matching accuracy without complex real-time decision logic.
Solution Approach 2:
The patent introduces a priority dimension to the lookup process, organizing entries in hierarchical priority levels. This dimensional organization allows the system to process multiple conditions by evaluating them in priority order using bitwise operations, transforming a complex multi-dimensional matching problem into a series of simpler sequential bitwise comparisons.
Data Source
AI summary
The present invention provides a method for packet processing according to a lookup table, comprising: receiving a packet, wherein the packet includes a packet header, and the packet header consists of control information; providing a lookup table with M entries, wherein each entry includes N conditions and a result/action indicator, and the M entries are sorted in a priority order; matching the information with the N conditions; and applying the result/action indicator in the matched entry with the highest priority on the packet.