SDN Switch Fabric Segmentation for Elephant Subflow Handling
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Solution Overview
Problem
Conventional SDN switches face inefficiencies in handling elephant subflows and switch partitioning, as they require extensive processing by powerful processors for deep packet inspection, leading to high costs and resource utilization inefficiencies.
Innovation Solution
The implementation of a network architecture that includes Network Flow Switch (NFX) circuits, which are less expensive and less powerful, and a Network Flow Processor (NFP) circuit, where NFX circuits handle packet forwarding without instruction-fetching processors, and the NFP circuit manages flow entries and configures NFX circuits to handle subflows efficiently, reducing the need for deep packet inspection and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional SDN switches use powerful processors for deep packet inspection and flow management, then packet forwarding accuracy and control are improved, but device cost and resource consumption increase significantly
Solution Approach 1:
The patent segments the SDN switch into two distinct parts: NFX circuits that handle packet forwarding using simple flow tables, and an NFP circuit that handles deep packet inspection and flow management. This segmentation allows the majority of packets to be forwarded by simple circuits while only requiring powerful processing for specific control functions, thereby reducing overall device complexity and cost while maintaining forwarding accuracy.
Solution Approach 2:
The patent introduces NFX circuits as intermediary components between incoming packets and the powerful NFP processor. These NFX circuits maintain simple flow tables and can forward packets directly without involving the powerful NFP processor, acting as an intermediary layer that handles routine forwarding while allowing the NFP to focus on complex control plane functions.
2Reliability
If SDN switches require extensive processing by powerful processors for each packet, then flow control precision is improved, but switching speed and resource utilization deteriorate
Solution Approach 1:
The patent divides packet processing into two segments: fast path processing by NFX circuits using simple flow table lookups for high-speed forwarding, and slow path processing by the NFP circuit for deep packet inspection and flow control decisions. This segmentation enables most packets to be switched at high speed while maintaining precise flow control for packets requiring inspection.
Solution Approach 2:
The patent applies partial action by having NFX circuits handle only the essential forwarding function using simple flow tables, while the more intensive deep packet inspection and flow control are applied selectively only when necessary by the NFP circuit. This partial application of processing power maintains switching speed while achieving sufficient flow control precision.
3Device complexity
If SDN switches use simple forwarding circuits without instruction-fetching processors, then device cost is reduced, but ability to handle dynamic flow changes and elephant subflows deteriorates
Solution Approach 1:
The patent segments flow handling responsibilities: NFX circuits with simple flow tables handle static, high-volume flows at line rate, while the NFP circuit handles dynamic flow changes, elephant subflow detection, and policy-based routing. This segmentation allows simple circuits to maintain low cost while the system as a whole retains dynamic adaptability through the NFP.
Solution Approach 2:
The patent implements feedback mechanisms where the NFP circuit monitors traffic patterns and dynamically updates flow tables in NFX circuits. This feedback loop enables simple NFX circuits to adapt to changing flow conditions and elephant subflows by receiving updated forwarding rules from the NFP, maintaining versatility without requiring complex processing in the NFX circuits themselves.
Data Source
AI summary
A Software-Defined Networking (SDN) switch that includes external network ports for receiving external network traffic onto the SDN switch, external network ports for transmitting external network traffic out of the SDN switch, a Network Flow Switch (NFX) integrated circuit that has multiple network ports and that maintains a flow table, another NFX integrated circuit that has multiple network ports and that maintains a flow table, and a Network Flow Processor (NFP) circuit that maintains a flow table. The NFP circuit couples directly to a network port of the first NFX integrated circuit but does not couple directly to any network port of the second NFX integrated circuit. The NFP circuit sends a flow entry to one NFX integrated circuit along with an addressing label and the NFX integrated circuit uses the addressing label to determine that the flow entry is to be forwarded to the second NFX integrated circuit.