Copyright (c) 2026 MindMesh Academy. All rights reserved. This content is proprietary and may not be reproduced or distributed without permission.

2.13.1. MAC Learning and Aging

Learning Process:
  1. Frame arrives on a switch port
  2. Switch reads the source MAC address
  3. Switch adds an entry: "MAC X is reachable via Port Y"
  4. Entry includes a timestamp for aging
Aging:
  • Default aging time: 300 seconds (5 minutes)
  • If no frames from a MAC address in that time, entry is removed
  • Aging keeps the table current and manageable
Switch# show mac address-table
          Mac Address Table
-------------------------------------------
Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    0011.2233.4455    DYNAMIC     Gi0/1
   1    0011.2233.4466    DYNAMIC     Gi0/2