Negwork Segmentation

LANs
  • Local Area Networks
    • A group of devices in the same broadcast domain
Virtual LANs
  • Virtual Local Area Networks
    • A group of devices in the same broadcast domain
    • Separated locally instead of physically
802.1Q trunking
  • Take a normal Ethernet frame
Data/Payload = 46 to 1500 bytes

  • Add a VLAN header in the frame


  • VLAN IDs - 12 bits long, 4094 VLANs
    • "Normal range" - 1 through 1005, "Extended range" - 1006 through 4094
    • 0 and 4,095 are reserved VLAN numbers
  • Before 802.1Q, there was ISL (Inter-Switch Link)
    • ISL is no longer used; everyone now uses the 802.1Q standard


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