3. Virtual Local Area Networks

Part 03 of Computer Networking Fundamentals: Virtual Local Area Networks (VLANs)

Virtual Local Area Networks

At the end of this episode, I will be able to:

1. Identify the characteristics and importance of VLANs.

Learner Objective: Identify the characteristics and importance of VLANs

Description: In this episode, the learner will be introduced to Virtual Local Area Networks or VLANs as well as identify the purpose of implementing them in networks.

• Introduction to Network Infrastructure
  • What are VLANs? - A logical division of networked devices connected within a local area networked
  • Why are VLANs important? - VLANs allow administrators to divide ports on a switch into logical groupings. This creates multiple logical switches out of a single physical switch. This can be done for performance and security.
  • Understanding communication types
    • Broadcast - A communication message that is sent by a single device to every other device connected to the switch.
      • One to all communication
    • Unicast - A communication message that is sent by a single device to another device on the network.
      • One to one communication
    • Multicast - A communication message that is sent by a single device to a group or subset of the devices on the network.
    • Broadcast domain - A group of devices connected to a network that receive broadcast communications. This grouping can be based on physical or logical segments.
    • Segments - A divison that splits a network into smaller parts.
  • Performance benefits - VLANs create virtual boundaries that reduce the amount of broadcast traffic between devices on a larger network and ease administration.
  • Security benefits - VLANs allow network administrators to group devices together to assign an enforce security policies. Devices within a VLAN can only communicate with other devices assigned to the same VLAN.
  • How are VLANs implemented?
    • VLANs require configuration of managed switches.
    • VLANs use tagging information that is inspected by the switch to determine which VLAN the communication belongs to.