Front-End Unit Buffering OpenFlow Control Messages
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Solution Overview
Problem
In networks using the OpenFlow protocol, the separation of switch and switch controller leads to increased load on the controller due to redundant packet processing, causing bottlenecks in packet transfer processing, and existing solutions do not adequately address the issue of redundant packet processing.
Innovation Solution
A network system with a front-end unit that temporarily stores control messages, buffers messages hitting a buffer flow entry, and transmits those not hitting any buffer flow entry to the switch controller without buffering, thereby reducing the transmission rate of control messages between the switch and the switch controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the OpenFlow switch transmits all received packets to the OpenFlow switch controller in an initial state or when the flow table is initialized, then the switch controller can determine the transfer method for all packets, but the load of the OpenFlow switch controller increases due to processing redundant packet data
Solution Approach 1:
The front-end unit performs preliminary actions by maintaining a buffer flow table that stores buffer flow entries corresponding to packets already transmitted to the switch controller. Before transmitting control messages to the switch controller, the front-end unit checks whether corresponding buffer flow entries exist in the buffer flow table, and only transmits messages for packets that have not been previously processed, thereby preventing redundant packet processing at the switch controller
Solution Approach 2:
The front-end unit acts as an intermediary between the OpenFlow switch and the OpenFlow switch controller. It intercepts control messages from the switch, checks the buffer flow table to determine whether the packets are redundant, and filters out duplicate messages before forwarding to the switch controller. This intermediary function reduces the load on the switch controller while ensuring it receives necessary control information
2Reliability
If the OpenFlow switch transmits data of all received packets to the OpenFlow switch controller when the flow table is initialized, then the switch controller can process packet transfer determination, but a bottleneck in packet transfer processing occurs due to excessive control messages
Solution Approach 1:
The front-end unit performs preliminary filtering by checking the buffer flow table before transmitting control messages to the switch controller. By maintaining records of previously transmitted packets in the buffer flow table, the front-end unit proactively identifies and filters out duplicate control messages, ensuring that only necessary messages are transmitted to the switch controller, thereby reducing the control message transmission rate and eliminating bottlenecks in packet transfer processing
Solution Approach 2:
The front-end unit extracts and removes redundant control messages from the stream before forwarding to the switch controller. By comparing incoming control messages against the buffer flow table, the front-end unit identifies and extracts only the necessary non-duplicate messages for transmission, leaving redundant messages behind, thus reducing the overall transmission rate and preventing bottlenecks
Data Source
AI summary
A transmission rate of a control message between a switch and a switch controller can be reduced. A network system includes the switch which transfers a packet based on a switch flow table, the switch controller and a front-end unit which relays the control message between the switch controller and the switch. The front-end unit includes a buffer, a flow table storage section and a buffer control section which buffers the control message which hits a buffer flow entry of the flow table in the buffer.