Forwarding Table Segmentation for Memory Optimization
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Solution Overview
Problem
Network devices face inefficiencies in memory resource utilization due to the storage of inactive routes in forwarding tables, which can lead to increased memory usage and delayed reactivation of routes when they become active again.
Innovation Solution
Implementing a method where inactive routes are removed from the forwarding plane portion of the forwarding table while maintaining their information in the control plane portion, allowing only active routes to be stored in the forwarding plane, and using a dynamic aging procedure to manage route retention and reactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If inactive routes are stored in the forwarding plane portion of the forwarding table, then route reactivation is faster, but memory utilization decreases
Solution Approach 1:
The forwarding table is segmented into two distinct portions: a control plane portion that stores all routes (including inactive ones) and a forwarding plane portion that stores only active routes. This segmentation allows the system to maintain fast reactivation by keeping route information in the control plane while optimizing memory usage in the forwarding plane by storing only currently active routes.
Solution Approach 2:
The control plane portion acts as an intermediary between the external routing information and the forwarding plane portion. When a route becomes inactive, its information is retained in the control plane, which then serves as a source for rapid reinstallation into the forwarding plane when the route becomes active again, eliminating the need to store inactive routes in the forwarding plane.
2Quantity of substance
If inactive routes are removed from the forwarding table, then memory utilization improves, but route reactivation is delayed
Solution Approach 1:
By segmenting the forwarding table into control plane and forwarding plane portions, the system can remove inactive routes from the forwarding plane (improving memory utilization) while maintaining them in the control plane (enabling fast reactivation). This resolves the contradiction by providing both benefits through strategic placement in different table portions.
Solution Approach 2:
The control plane portion performs preliminary action by maintaining route information in advance before it is needed in the forwarding plane. When a route becomes active again, the information is already prepared in the control plane, allowing for rapid reinstallation into the forwarding plane without delay.
3Ease of operation
If all routes are stored in both control plane and forwarding plane portions, then route management is simplified, but memory usage increases
Solution Approach 1:
Different portions of the forwarding table are assigned different qualities and functions: the control plane portion stores all routes for comprehensive management, while the forwarding plane portion stores only active routes for efficient memory usage. This local differentiation allows each portion to optimize for its specific purpose while working together as a unified system.
Data Source
AI summary
A device may determine that a route is inactive. Information identifying the route may be stored in a forwarding plane portion of a forwarding table and a control plane portion of the forwarding table. The route may be associated with directing network traffic toward an endpoint network device. The device may remove the information identifying the route from the forwarding plane portion of the forwarding table without removing the information identifying the route from the control plane portion of the forwarding table based on determining that the route is inactive. The device may route network traffic based on the forwarding table after removing the information identifying the route from the forwarding plane portion of the forwarding table without removing the information identifying the route from the control plane portion of the forwarding table.