Relay Apparatus MAC Table Entry Replacement
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Solution Overview
Problem
In Ethernet networks, especially in vehicle communication systems, the MAC address table often becomes full, leading to flooding when an unregistered device sends a frame, as there is no available entry to record the transmission source MAC address, causing bandwidth issues and potential erasure of necessary MAC addresses with aging, which does not effectively prevent flooding.
Innovation Solution
A relay apparatus that specifies and updates the entry with the lowest communication frequency in the MAC address table when a frame from an unrecorded device is received, ensuring that the transmission source MAC address and port are recorded, thereby preventing flooding without relying on aging mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the MAC address table is filled with recorded entries, then the recording capacity is maximized, but the ability to record new transmission source MAC addresses is lost
Solution Approach 1:
The patent implements dynamic entry replacement in the MAC address table by identifying and replacing the entry with the lowest communication frequency when the table is full. This dynamic adjustment allows the system to adapt to changing network conditions and prioritize recording of actively communicating devices while maintaining the ability to record new MAC addresses.
Solution Approach 2:
The patent changes the parameter selection criterion from static (e.g., first-come-first-served or random) to dynamic based on communication frequency. By using communication frequency as the replacement criterion, the system optimizes which MAC address entries to retain and which to replace, balancing table capacity utilization with adaptability to new devices.
2Productivity
If aging mechanism is used to manage full MAC address table, then old entries are automatically removed, but important MAC addresses may be erased prematurely
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring communication frequency for each MAC address entry. This feedback information is used to determine which entry to replace when the table is full, ensuring that entries with higher communication frequency (more important connections) are retained while less active entries are replaced, thus preventing premature erasure of important MAC addresses.
Solution Approach 2:
The patent replaces the time-based aging parameter with a communication-frequency-based parameter for determining entry replacement. This parameter change allows the system to prioritize retention of actively used MAC addresses over simply maintaining entries based on their age, improving both management efficiency and reliability.
3Ease of operation
If flooding is performed when MAC address table is full, then all frames are transmitted to all ports, but network bandwidth is wasted and performance degrades
Solution Approach 1:
The patent performs preliminary action by proactively maintaining accurate MAC address to port mappings in the table even when full, using communication frequency to prioritize entries. This preliminary maintenance of table accuracy prevents the need for flooding, as the switch can continue to make informed forwarding decisions based on the existing table entries.
Data Source
AI summary
A relay apparatus is provided to specify, in a plurality of recording areas in an information table, a target recording area being a recording area which records a transmission source data-item included in a frame and indicating as transmission source a device having a lowest frequency of communication via the relay apparatus, in response to receiving an unrecorded frame via a port of a plurality of ports under a fully recorded state of the plurality of recording areas. The unrecorded frame is a frame including a transmission source data-item that is not recorded in any of the plurality of recording areas. The fully recorded state of the plurality of recording areas is a state where the transmission source data-item and the port data-item are recorded fully in each of all the plurality of recording areas included in the information table.