Token Circulation Management for Ethernet Transmission Delay
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Solution Overview
Problem
In communication systems using a token passing method over Ethernet, there is a delay in data transmission after acquiring a token frame, leading to deviations in the order of data transmission and scheduling issues among nodes.
Innovation Solution
A communication management apparatus that includes a token-circulation-order storing unit, a token-frame receiving unit, and a data-frame-communication processing unit to determine and manage the transmission rights and frame units, allowing nodes to transmit data only when they have the necessary rights and within specified frame limits, reducing the time required for data transmission and ensuring ordered transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a communication node calculates the amount of data to be transmitted and compares it with the allowed transmission data amount in the token frame, then the transmission control is achieved, but the time required until data transmission after acquiring the token frame increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the amount of data to be transmitted in the communication node before acquiring the token frame. When the token frame is acquired, the node immediately compares the pre-calculated data amount with the allowed transmission data amount in the token frame, eliminating the need for real-time calculation and thus reducing the time required until data transmission begins
2Reliability
If data transmission is delayed until the next token frame acquisition, then transmission control is maintained, but the transmission order deviates from the data generation order
Solution Approach 1:
The patent applies feedback by having each communication node monitor the token frame circulation and track which nodes have already transmitted data. When a node acquires the token frame, it checks whether previous nodes in the circulation order have completed transmission, and only transmits when appropriate, ensuring data is sent in the correct order while maintaining transmission control through the token mechanism
3Reliability
If the allowed transmission data amount is set to 0 in the token frame, then data transmission is prevented for that node, but the node cannot transmit even when data amount is small
Solution Approach 1:
The patent applies dynamics by making the allowed transmission data amount in the token frame variable rather than fixed at zero. The management station dynamically adjusts the allowed transmission data amount based on the actual data amount that each communication node needs to transmit, allowing nodes to transmit appropriate amounts of data while maintaining overall transmission control, thus providing both reliability and operational flexibility
Data Source
AI summary
A communication management apparatus includes a token-circulation-order-information storing unit that stores token circulation order, a token-frame processing unit that determines whether transmission right acquiring apparatus information of the token frame indicates the own apparatus and transmits a token frame in which first transmission right acquisition determination information indicating a sequence number of a communication apparatus that can acquire a transmission right in the token circulation order, second transmission right acquisition determination information indicating the number of frames that can be transmitted during one token frame circulation, and transmission right acquiring apparatus information indicating the next transmission destination of the token frame after the own apparatus acquired from the token circulation order are set, and a data-frame-communication processing unit that transmits and receives the data frame, thereby to reduce time required until a communication node that acquired the token frame transmits data.