OpenFlow Controller Synchronization via Communication Apparatus
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Solution Overview
Problem
In OpenFlow communication systems, multiple controllers managing an OpenFlow switch struggle with synchronization when network failures occur between controllers, leading to disconnection and inability to exchange necessary information for interoperation.
Innovation Solution
A communication system where a communication apparatus processes packets according to control information set by control apparatuses, allowing first and second control apparatuses to transmit and receive information necessary for interoperation via the communication apparatus, even in the presence of network failures, using the OpenFlow protocol's Packet-Out message or Vendor-defined messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple controllers directly communicate with each other to exchange status information, then synchronization between controllers is achieved, but network failures between controllers cause disconnection and inability to exchange information
Solution Approach 1:
The patent introduces a communication apparatus as an intermediary between multiple controllers. Controllers exchange status information by communicating with the communication apparatus rather than directly with each other. The communication apparatus receives status information from one controller and forwards it to other controllers, enabling indirect communication that maintains synchronization even when direct controller-to-controller communication fails due to network issues.
2Loss of information
If controllers exchange status information directly, then interoperation information is synchronized, but network failures prevent information exchange
Solution Approach 1:
The communication apparatus serves as a reliable intermediary that guarantees information exchange between controllers. When one controller sends status information to the communication apparatus, it is stored and subsequently forwarded to all other controllers. This intermediary mechanism ensures that information is not lost even when direct communication paths between controllers fail, as the communication apparatus maintains the information and redistributes it through alternative paths.
3Reliability
If controllers use indirect communication through communication apparatus, then information exchange continues during network failures, but communication overhead increases
Solution Approach 1:
The communication apparatus performs preliminary actions by pre-establishing communication channels and maintaining status information buffers. When status information arrives from one controller, the communication apparatus immediately stores it and prepares it for forwarding. This preliminary preparation ensures that when other controllers request status information, it is already available for immediate transmission, reducing the actual communication delay despite the indirect path.
Data Source
AI summary
A communication system includes a communication apparatus that processes a packet according to control information set by a control apparatus; a first control apparatus that controls the communication apparatus by setting the control information in the communication apparatus; and a second control apparatus that operates in concert with the first control apparatus. The first control apparatus transmits information necessary for interoperation between the first and second control apparatuses to the second control apparatus via the communication apparatus.