Layer 2 Switching
Switches are the foundation of the LAN. They forward frames based on MAC addresses, isolate collision domains, and provide the physical connectivity for end users.
VLANs & Trunking
Logical segmentation of Broadcast Domains using 802.1Q tagging. Deep dive into Native VLANs, DTP, and VTP risks.
Deep Dive →Spanning Tree (STP)
Preventing Layer 2 loops. Understanding Root Bridge election, Port Roles, and modern convergence with RSTP/MST.
Deep Dive →EtherChannel
Link Aggregation (LACP) for redundancy and bandwidth. Load balancing algorithms and hashing mechanics.
Deep Dive →Core Concepts
The MAC Address Table (CAM)
A switch operates at Layer 2, using the Source MAC of incoming frames to populate its Content Addressable Memory (CAM) table.
- Learning: Frame arrives on Port 1. Switch records {Src MAC: AA:BB, Port: 1, VLAN: 10}.
- Aging: Entries expire after 300 seconds (default) of inactivity.
- Flooding (BUM Traffic): If the Destination MAC is Unknown Unicast, Broadcast (FF:FF...), or Multicast, the frame is flooded out all ports (except ingress).
- Forwarding: If Destination MAC is known, it is switched only to the destination port (Unicast).