Relay Device Selective Flooding Reduces Traffic Load
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Solution Overview
Problem
Conventional relay devices experience high traffic loads on communication devices when receiving frames with unlearned destination addresses, especially when the output port is connected to a branch circuit.
Innovation Solution
The relay device includes a timer unit that starts clocking when the address table is cleared during a trunk network path switch, and a destination determination unit that transfers frames to a port connected to the trunk circuit if the port number is not found within a set time, thereby reducing unnecessary traffic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flooding is performed for all ports except the receiving port when the address table is cleared, then the frame can be relayed to the destination communication device even when the destination address is unlearned, but the traffic load on communication devices is increased
Solution Approach 1:
The patent applies local quality by differentiating between trunk ports and branch ports in the flooding process. When the address table is cleared and a frame with an unlearned destination address is received, the relay device performs flooding only to trunk ports (ports connected to other relay devices in the trunk network) rather than to all ports. This selective flooding approach maintains the ability to relay frames to destinations while reducing unnecessary traffic load on communication devices connected to branch ports.
2Reliability
If flooding is performed to all ports including branch ports when the address table is cleared, then the frame can reach the destination even through unnecessary paths, but communication speed and quality of the communication device are badly affected
Solution Approach 1:
The patent differentiates between trunk ports and branch ports to apply selective flooding. By identifying that branch ports connect to communication devices that do not need to receive flooded frames during address table clearing, the relay device restricts flooding to trunk ports only. This preserves frame delivery capability through the trunk network while preventing degradation of communication speed and quality for devices on branch networks.
3Reliability
If flooding is performed to all ports when the address table is cleared, then the frame can be transferred to the destination communication device, but the number of unnecessary frames transferred is increased
Solution Approach 1:
The patent implements local quality by applying different flooding behaviors to different port types. When the address table is cleared and a frame arrives with an unlearned destination address, the relay device determines whether to flood based on the port type: frames are flooded to trunk ports to maintain transfer capability, but not flooded to branch ports where they would constitute unnecessary transfers. This reduces the number of unnecessary frames transferred while preserving essential frame transfer functionality.
Data Source
AI summary
The conventional relay device has a problem that a traffic load on a communication device is large when an output port of a frame including a destination address, which an address table has not learned yet, is a port connected to a branch circuit, since flooding is performed on all ports except for a port that has received the frame. A relay device (21) is provided with a destination determination unit (41) to transfer, when a time clocked by a timer unit (40) to start clocking is within a set time, a frame to ports (511 and 512) connected to trunk circuits (61 and 64), and when the time clocked by the timer unit (40) exceeds the set time, to transfer the frame to the ports (511 and 512) connected to the trunk circuits (61 and 64) and a port (513) connected to a branch circuit (65), in a case wherein it is impossible for a search unit (43) to obtain from a first storage unit (33) a port number corresponding to a destination address included in the frame received, and the first storage unit (33) is cleared.