1ī¸âŖ Switch Has a MAC Address Table (CAM Table)
The switch maintains a dynamic table that maps devices to ports:
| Device MAC Address | Port Number |
|---|
| AA:BB:CC:DD:EE:01 | Port 1 |
| AA:BB:CC:DD:EE:02 | Port 3 |
This table is created automatically as traffic passes.
2ī¸âŖ Learning Phase (MAC Learning)
Whenever the switch receives a frame:
- It checks the Source MAC.
- It maps that address to the incoming port.
- If the MAC is not in the table, it adds a new entry.
- If it already exists, it refreshes the timer.
3ī¸âŖ Forwarding Phase (Decision Making)
The switch checks the Destination MAC and takes one of 3 actions:
đ A. Unicast
If Dest MAC is Known:
đ Sends frame ONLY to that specific port.
đ B. Flooding
If Dest MAC is Unknown:
đ Floods out ALL ports except the incoming one.
đ C. Filtering
If Source & Dest are on Same Port:
đ The switch DROPS the frame.