Switching (Layer 2)

VLANs, trunking, STP, and switching fundamentals for CCNA.

▶Switching (Layer 2 Overview)

Layer 2 switching is responsible for forwarding frames using MAC addresses inside a LAN.

▶MAC Address Table

Switch learns MAC addresses and maps them to specific ports.

▶Frame Forwarding

Switch forwards frames based on MAC lookup in the table.

▶VLANs

Virtual LANs logically separate broadcast domains inside a switch.

▶Trunking (802.1Q)

Trunk links carry multiple VLANs between switches.

▶Spanning Tree Protocol (STP)

Prevents Layer 2 loops by blocking redundant paths.

▶EtherChannel

Combines multiple physical links into one logical link for redundancy and speed.

▶Inter-VLAN Routing

Allows communication between VLANs using a Layer 3 device.