Switch MAC Table Learning to Block Unknown Unicast Flooding

Solution Overview

Problem

Current Layer 2 switching protocols, such as Spanning Tree Protocol and Multiple Spanning Tree Protocol, lead to underutilization of network capacity due to unnecessary bandwidth consumption and buffer utilization caused by flooding unknown unicast traffic across all ports, which results in inefficient bandwidth usage and processing delays.

Innovation Solution

Implementing a switch with a MAC address table that learns and remembers previously connected MAC addresses, allowing only unicast traffic to be forwarded to ports with known destinations, thereby blocking unknown unicast traffic within the same broadcast domain and avoiding L2 flooding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If L2 switches forward unknown unicast traffic to all MAC addresses, then traffic can reach its destination, but unnecessary bandwidth consumption and buffer utilization occur

Engineering Contradiction:

Improvetraffic deliveryVSAvoidbandwidth consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The switch performs preliminary learning of MAC addresses and their associated ports before traffic forwarding occurs. The MAC address table is built in advance by monitoring incoming traffic and recording source MAC addresses with their corresponding ingress ports. This preliminary action enables the switch to make informed forwarding decisions without needing to flood unknown unicast traffic across all ports.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If L2 switches forward unknown unicast traffic to all MAC addresses, then traffic can reach its destination, but processing delays occur

Engineering Contradiction:

Improvetraffic deliveryVSAvoidprocessing delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The switch performs preliminary learning of MAC addresses and their associated ports before traffic forwarding occurs. The MAC address table is built in advance by monitoring incoming traffic and recording source MAC addresses with their corresponding ingress ports. This preliminary action enables the switch to make informed forwarding decisions without needing to flood unknown unicast traffic across all ports.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If redundant links are activated for failover, then network reliability improves, but network loops are created

Engineering Contradiction:

Improvefailover capabilityVSAvoidnetwork loops

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system dynamically adjusts link states based on real-time network conditions and failover requirements. When a primary link fails, previously blocked redundant links are activated to maintain connectivity. This dynamic approach allows the network to maintain loop-free topology during normal operation while providing failover capability when needed, resolving the contradiction between reliability and loop prevention.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10075369B2Systems and methods for improved switch performance by preventing flooding

Publication Date: 2018.09.11 DELL PROD LP

AI summary

Aspects of the present invention include directing traffic in data communications systems. In embodiments of the present invention the traffic is directed based on a Media Access Control (MAC) address table. In embodiments of the present invention traffic directed to an unknown port is blocked to all ports that are in the MAC address table.