SDN Forwarding Table Precedence Management
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Solution Overview
Problem
In software-defined networking (SDN), conventional control planes lack a mechanism to distribute precedence information of forwarding tables to the forwarding plane, leading to inadequate resource allocation and traffic interruption due to the inability to determine which entries should be discarded in shared forwarding tables.
Innovation Solution
A method where a network device in the control plane sends precedence information to a network device in the forwarding plane, allowing it to intelligently manage shared forwarding tables by inserting or evicting entries based on priority, ensuring that higher-precedence entries are allocated necessary resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple forwarding tables share the same common forwarding table in SDN, then resource utilization and scalability are improved, but the ability to guarantee performance requirements for different forwarding tables deteriorates
Solution Approach 1:
The patent assigns different precedence values to different forwarding tables, allowing each table to have differentiated priority levels within the shared hardware resource. This enables high-priority tables (like VT tables) to guarantee performance while low-priority tables share remaining resources, resolving the contradiction between resource utilization and performance guarantee.
2Device complexity
If precedence information is not distributed to the forwarding plane, then system complexity is reduced, but the ability to intelligently manage forwarding table entries deteriorates
Solution Approach 1:
The patent introduces precedence information as an intermediary parameter that enables the forwarding plane to make intelligent decisions about entry insertion and eviction. This simple numerical parameter acts as a mediator between the control plane's forwarding table definitions and the forwarding plane's resource allocation decisions, resolving the contradiction between system simplicity and management capability.
3Device complexity
If the shared forwarding table has limited hardware resources, then device cost and complexity are reduced, but the ability to accommodate all forwarding table entries deteriorates
Solution Approach 1:
The patent implements a dynamic entry eviction mechanism where low-precedence entries are automatically discarded when high-precedence entries need to be inserted. This allows the system to maintain a limited number of hardware resources while effectively accommodating a larger total number of forwarding table entries across different tables, as lower-priority entries are temporarily replaced when needed.
Data Source
AI summary
Exemplary methods for maintaining a shared forwarding table in a forwarding plane include a first network device operating in a forwarding plane receiving information associated with a first forwarding table from a second network device operating in a control plane, the information including a plurality of entries and precedence information, the precedence information indicating a priority of the plurality of entries of the first forwarding table. The methods further include for each entry of the first forwarding table, determining whether the entry should be inserted in the shared forwarding table based on the precedence information of the first forwarding table and precedence information contained in the shared forwarding table, wherein the precedence information contained in the shared forwarding table indicates a priority of each corresponding entry stored in the shared forwarding table.