Look-up Table Creation for SDN Forwarding Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In SDN network architectures, the use of TCAM circuits for mask matching in look-up tables leads to high gate circuit consumption and power consumption due to the need for extensive chip resources.
Innovation Solution
A method for creating and querying look-up tables that allows for different look-up modes (linear, hash, longest match, and mask) to be used, reducing the reliance on TCAM circuits by using alternative index parameters such as keywords and mask lengths, thereby optimizing resource usage and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mask matching is performed using TCAM circuits in look-up tables, then forwarding accuracy is improved, but chip resource consumption and power consumption increase significantly
Solution Approach 1:
The patent segments the look-up table into multiple parts: a first look-up table using TCAM circuits for mask matching (for critical forwarding rules requiring high accuracy) and a second look-up table using simplified matching logic (for less critical rules). This segmentation allows the system to maintain forwarding accuracy for important rules while reducing overall power consumption by avoiding TCAM usage for all rules.
Solution Approach 2:
The patent applies different matching qualities to different parts of the forwarding rule set. TCAM-based mask matching is applied locally to specific forwarding rules that require high precision, while other rules use simpler matching mechanisms. This local application of high-quality matching reduces overall resource consumption while maintaining necessary accuracy where required.
2Reliability
If mask matching is performed using TCAM circuits in look-up tables, then forwarding accuracy is improved, but the quantity of gate circuits on the chip increases
Solution Approach 1:
The patent divides the forwarding rule processing into multiple segments, with only critical rules processed by TCAM circuits using mask matching. Non-critical rules are processed using simplified matching logic in a second look-up table. This segmentation reduces the total number of TCAM circuits needed, thereby reducing gate circuit quantity and chip complexity while maintaining forwarding accuracy for important rules.
Solution Approach 2:
The patent applies full mask matching capability only partially - specifically to the extent necessary for critical forwarding rules. For other rules, a reduced matching capability suffices. This partial application of the complex TCAM-based mask matching reduces the quantity of gate circuits required while maintaining adequate forwarding accuracy for the system's needs.
3Stability of the object's composition
If uniform mask matching mode is used for all look-up tables, then forwarding rule consistency is maintained, but resource efficiency and power consumption are degraded
Solution Approach 1:
The patent applies different matching modes to different look-up tables based on their specific requirements. The first look-up table uses mask matching mode for rules requiring precise matching, while the second look-up table uses simplified matching for rules where approximate matching suffices. This local differentiation maintains consistency where needed while improving resource efficiency and reducing power consumption overall.
Solution Approach 2:
The patent changes the matching parameter from uniform mask matching across all tables to differentiated matching modes. By adjusting the matching parameter (from full mask matching to simplified matching) based on the specific requirements of different forwarding rules, the system maintains necessary consistency while significantly improving resource efficiency and reducing power consumption.
Data Source
AI summary
Embodiments of the present disclosure discloses a look-up table creation method and query method. The creation method includes: receiving a look-up table create message sent by a controller, where the look-up table create message includes an identifier of a look-up table and a look-up mode of the look-up table; creating a look-up table according to the look-up table create message and setting a look-up mode of the look-up table; receiving an entry add message sent by the controller, where the entry add message includes a to-be-added forwarding action and an index parameter of the forwarding action; and adding, according to the entry add message, an entry corresponding to the entry add message to the look-up table.