Flow Identification Tunneling for OpenFlow and Layer 2 Switch Interoperability
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Solution Overview
Problem
In environments where OpenFlow switches and layer 2 switches coexist, the existing tunneling methods face limitations due to constraints on the number of communication terminals allowed and increased network load, primarily because of the reliance on MAC address tables and IP address translation, which can lead to excessive broadcast packets and high loads on the network.
Innovation Solution
A communication system that includes a first node for packet forwarding using an address table and second nodes with packet processing units, where a control apparatus determines packet forwarding paths and modifies packet headers to include flow identification information, allowing tunneling without relying on the number of MAC addresses and reducing network load by optimizing packet forwarding paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing tunneling methods are used in environments where OpenFlow switches and layer 2 switches coexist, then packet forwarding can be achieved, but the number of communication terminals is constrained and network load increases
Solution Approach 1:
The patent introduces a control apparatus as an intermediary that manages packet forwarding between OpenFlow switches and layer 2 switches. The control apparatus maintains a flow table that maps flow identification information to forwarding paths, acting as a mediator that translates between the different switching mechanisms without requiring MAC address translation or excessive broadcast packets
Solution Approach 2:
The patent changes the parameter used for packet forwarding from MAC addresses to flow identification information. By using flow IDs instead of MAC addresses for tunneling identification, the system eliminates the constraint on the number of communication terminals while maintaining tunneling functionality across heterogeneous switch types
2Adaptability or versatility
If existing tunneling methods are used in environments where OpenFlow switches and layer 2 switches coexist, then packet forwarding can be achieved, but network load increases due to excessive broadcast packets
Solution Approach 1:
The control apparatus serves as an intermediary that optimizes packet forwarding paths and prevents excessive broadcast packets. By managing the flow table and making intelligent forwarding decisions, it reduces unnecessary network traffic and lowers overall network load while maintaining tunneling functionality
Solution Approach 2:
The system enables packets to carry flow identification information that allows them to be routed automatically through the tunnel without requiring broadcast packets for path discovery. Each packet serves itself by containing the necessary flow ID for direct routing, eliminating the need for broadcast-based path finding
3Adaptability or versatility
If MAC address tables and IP address translation are used for tunneling, then packet forwarding between different switch types is enabled, but the system becomes complex and network load increases
Solution Approach 1:
The control apparatus acts as a centralized intermediary that manages all tunneling operations, eliminating the need for complex distributed MAC address translation and IP address mapping logic in each switch. The control apparatus maintains a unified flow table that simplifies the overall system architecture by centralizing the intelligence required for heterogeneous switch interoperability
Data Source
AI summary
When calculating a forwarding path for a packet, a control apparatus determines a second node on the exit side of the packet forwarding path and an output port thereof. Next, the control apparatus sets in a second node located upstream of the first node on the packet forwarding path a packet handling operation for writing flow identification information associated with the output port in a packet header field not to be referred to when the first node forwards the packet and rewriting address information in the packet header such that the packet arrives at the second node on the exit side, and then causing the packet to be forwarded. A packet handling operation for causing the packet with the flow identification information given thereto to be transmitted from the port associated with the flow identification information is set in the second node on the exit side.