OpenFlow Switch Terminal Detection via Source MAC
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Solution Overview
Problem
Large-sized networks face inefficiencies in flow table usage and lack terminal location information when no broadcast packets are transmitted, making it difficult to manage and optimize network behavior.
Innovation Solution
A network system where a switch compares source MAC address and port information with stored data, sending inquiry information to a controller if a match is not found, allowing the controller to manage and update terminal location information and set flow entries for route control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a switch in a large-sized network relies on traditional flow table usage and broadcast packets for terminal detection, then the network can operate with basic packet forwarding, but terminal location information cannot be obtained when no broadcast packets are transmitted, and flow table resources are inefficiently utilized
Solution Approach 1:
The controller proactively sends packet-in messages to switches to obtain terminal location information before broadcast packets are transmitted. This preliminary action ensures that terminal location information is already available in the controller when needed for route control, eliminating the problem of information loss during data plane operations.
Solution Approach 2:
The controller acts as an intermediary between switches and terminals for obtaining location information. Instead of relying on switches to detect terminals independently or using broadcast packets, the controller mediates by sending packet-in messages to switches, which then forward these messages to terminals to obtain their location information centrally.
2Loss of information
If the controller sends packet-in messages to all switches to obtain terminal location information, then complete terminal information can be collected, but the number of inquiries increases unnecessarily, consuming additional network resources
Solution Approach 1:
The controller applies different handling strategies to different switches based on local conditions. For switches that already have terminal location information or where terminals are known to be connected, the controller does not send packet-in messages. Packet-in messages are only sent to switches where terminal location information is actually needed and not yet available, optimizing resource usage while maintaining information completeness.
Solution Approach 2:
Instead of sending packet-in messages to all switches (excessive action), the controller sends messages only to the necessary subset of switches where terminal location information is missing (partial action). This selective approach achieves complete terminal information collection without the resource waste of universal querying.
3Ease of operation
If terminal location information is obtained through broadcast packets, then the detection method is simple, but it cannot determine terminal locations when no broadcast packets are transmitted
Solution Approach 1:
The patent replaces the mechanical broadcast packet mechanism with a control plane-based packet-in message system. Instead of relying on data plane broadcast packets to carry location information, the controller uses the control plane to send packet-in messages to switches, which then obtain terminal information through a different mechanism (packet-in flow) that does not depend on broadcast traffic.
Data Source
AI summary
In an OpenFlow network, it is determined which port of which node device a terminal connected to a group of node devices is connected to, by only using the source MAC address and port number of a packet transmitted from the terminal. Specifically, the node device compares a set of the port number and source MAC address information of a packet transmitted from the terminal to the node device with a set(s) of a port number and MAC address information held in a preliminary search table to check whether they match each other. When the comparison does not result in a match, the node device notifies the controller by using the inquiry information (packet-in) function of OpenFlow. Furthermore, the node device compares the destination MAC address information of the packet with a set(s) of MAC address information held in a final search table to check whether they match each other.