Frame-Forwarding Process

To successfully troubleshoot Layer 2 forwarding issues, you need a solid understanding of how a switch operates. You would have learned this back in CCNA Routing and Switching. However, we spend time here reviewing switch operations because our troubleshooting efforts will be based on this knowledge. This section reviews how a switch populates its MAC address table and how it decides what to do with a frame based on the information in the MAC address table.


Unlike Ethernet hubs, which take bits in one port and send those same bits out all other ports, Ethernet switches learn about the devices connected to their ports. ...

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