Single-Port Ethernet Node for Low-Cost Multi-Drop Networking
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Solution Overview
Problem
Network switch devices with multiple ports are costly for certain applications due to the inclusion of hardware and software for each port, making them prohibitive.
Innovation Solution
Implementing a low complexity multi-drop network using half-duplex devices with Ethernet network interface modules (EIMs) that lack processors or controllers, utilizing hardware state machines and logic circuitry to manage data transmission and collision handling on a shared network link.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a network switch device includes multiple ports with hardware and software for each port, then communication capability is improved, but device complexity and cost increase
Solution Approach 1:
Multiple Ethernet ports are merged into a single physical interface. The network interface module includes a single half-duplex port that couples to the shared bus, eliminating the need for separate hardware for each port while maintaining multi-point communication capability through the multi-drop network architecture.
Solution Approach 2:
The single half-duplex port serves multiple functions by communicating with multiple network nodes through the shared bus. The port can dynamically communicate with different nodes (sensors, actuators, master nodes) depending on the protocol state and address matching, making it a universal interface for all network traffic.
2Adaptability or versatility
If a network switch device includes multiple ports with hardware and software for each port, then communication capability is improved, but cost increases
Solution Approach 1:
Multiple Ethernet ports are merged into a single physical interface. The network interface module includes a single half-duplex port that couples to the shared bus, eliminating the need for separate hardware for each port while maintaining multi-point communication capability through the multi-drop network architecture.
Solution Approach 2:
The patent replaces expensive multi-port switch hardware with inexpensive single-port half-duplex devices. Each network node uses a simple network interface module without requiring processors or controllers, significantly reducing the cost per node while maintaining network functionality through the shared bus architecture.
3Reliability
If traditional network switches are used, then communication reliability is maintained, but polling requirements increase latency
Solution Approach 1:
The network interface module autonomously monitors the shared bus for traffic directed to its associated network node without requiring polling by a master controller. When the node's address matches the destination address in received traffic, the module automatically processes the data, eliminating polling delays and reducing latency while maintaining reliable communication.
Data Source
AI summary
A network interface module for coupling a host device to a switched network as a network node is described. The network interface module comprises a single half-duplex port for communicatively coupling to a shared bus of the switched network, at least one frame queue sized to store one multicast read frame received via the shared bus, and logic circuitry. The logic circuitry is configured to decode a read command for the interface module included in a payload of the multicast read frame that includes multiple read commands for other network nodes of the switched network, and transmit a response frame including read data on the shared bus when detecting the shared bus is available for transmitting.