Smart Switch Connection Tables for Idle Flow Offloading
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Solution Overview
Problem
Existing data processing units (DPUs) in smart switches and SDN appliances face challenges in managing large numbers of idle connections, which consume memory and processing resources, leading to performance issues and potential application failures due to TCP time-outs.
Innovation Solution
Implementing an overflow connection table to hold underutilized connections, offloading them to an additional processor and memory subsystem, allowing for a larger active connection table without burdening the fast path with idle connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the connection table size is increased to maintain more connections, then the number of maintained connections is improved, but memory consumption and processing resource usage increase
Solution Approach 1:
The connection table is segmented into two parts: an active connection table for frequently accessed connections and a dormant connection table for idle connections. This segmentation allows the system to maintain a large total number of connections while keeping the active table small and efficient, thus resolving the contradiction between maintaining more connections and reducing resource consumption.
Solution Approach 2:
Idle connections are extracted from the active connection table and moved to a separate dormant connection table. This extraction removes the burden of managing large numbers of inactive connections from the fast path processing, allowing the active table to remain small and efficient while still maintaining the ability to track a large total number of connections.
2Reliability
If idle connections are kept in the active connection table, then connection state information is preserved, but fast path processing performance deteriorates
Solution Approach 1:
The connection table is divided into active and dormant segments, allowing the system to preserve connection state information for all connections while isolating idle connections from the fast path. This segmentation ensures that active connections are processed efficiently while dormant connections maintain their state information without impacting performance.
Solution Approach 2:
The dormant connection table acts as an intermediary storage mechanism that preserves connection state information without interfering with fast path processing. Connections can be moved between active and dormant tables based on their activity status, allowing the system to maintain reliability while protecting fast path performance.
3Quantity of substance
If the connection table is expanded to hold more connections, then connection capacity is improved, but resource burden on the fast path increases
Solution Approach 1:
The connection management system is segmented into two independent tables: active connections handled by the fast path and dormant connections handled separately. This segmentation allows the system to expand total connection capacity without increasing the burden on the fast path, as dormant connections are managed independently with simpler resource requirements.
Data Source
AI summary
Techniques are disclosed for managing states at a networking device configured to track connections or bidirectional flows of a communication session in a software defined network (SDN). The networking device has an active processing engine and a passive processing engine. The connection record for an idle connection is maintained in the connection table stored at the passive processing engine, thereby allowing the passive processing engine to maintain connection state information for the idle connection and avoid storing connection state information for the idle connection at the active processing engine.