Relay Device Filtering Clock-Time Synchronization Frames
Solution Overview
Problem
The high cost of precision time protocol (PTP) grand master (GM) devices with multiple clock-time information distribution ports is a significant barrier to achieving reliable and cost-effective clock-time synchronization in industrial networks, as the price of GMs increases with the number of ports, leading to increased costs for redundancy and fault tolerance.
Innovation Solution
A communication system utilizing relay devices with multiple ports and processing circuitry that filters and transfers only clock-time synchronization frames, allowing for clock-time synchronization between networks without the need for multiple expensive GMs, thereby reducing costs while maintaining high reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple expensive GMs with multiple clock-time information distribution ports are arranged on a network to enhance fault tolerance, then reliability is improved, but cost increases
Solution Approach 1:
The patent introduces relay devices as intermediary components between the GM and end devices. These relay devices receive clock-time synchronization frames from the GM, filter out other frames, and forward only the clock-time synchronization frames to connected devices. This intermediary approach allows a single GM to serve multiple networks through relay devices, eliminating the need for multiple expensive GMs while maintaining fault tolerance and reliability
Solution Approach 2:
The relay devices create a functional copy of the clock-time distribution capability. Instead of requiring multiple physical GMs, the relay devices replicate the clock-time synchronization function by filtering and forwarding the synchronization frames from a single GM to multiple networks, thereby achieving redundancy and fault tolerance at lower cost
2Reliability
If a GM distributes clock-time information from multiple clock-time information distribution ports, then fault tolerance is improved, but the price of the GM increases in proportion to the number of ports
Solution Approach 1:
The patent segments the clock-time distribution function across multiple devices. Instead of concentrating all distribution ports in a single expensive GM, the system divides the function: the GM generates clock-time synchronization frames, while relay devices handle the distribution to multiple networks. This segmentation allows each device to have fewer ports, reducing the overall system cost while maintaining the ability to serve multiple networks
Solution Approach 2:
The relay devices are designed with multi-functionality, serving both as network traffic relays and as clock-time synchronization distributors. By making the relay devices universal components that can perform multiple functions, the system eliminates the need for dedicated multiple-port GMs, as the relay devices can distribute clock-time information to multiple networks using their existing port infrastructure
Data Source
AI summary
A relay device includes a plurality of physical ports (111-1 to 111-N) that receive frames, and a layer-2 protocol processing unit (113) that transfers the frame received by one of the physical ports (111-1 to 111-N) from at least one of the physical ports (111-1 to 111-N). The layer-2 protocol processing unit (113) has a filtering function for blocking frames other than a clock-time synchronization frame during transfer involving a port selected from the plurality of physical ports (111-1 to 111-N) as a port that relays only the clock-time synchronization frame used for synchronizing clock time.