Virtual Local Area Network (VLAN)

Virtual Local Area Network (VLAN)

• a logical network division that separates a physical network into multiple broadcast domains

• groups devices based on function or department, not only physical location or cabling

• implemented through software, not hardware

• advantages: greater flexibility in organizing the network, more efficient use and management of network resources

LAN vs VLAN

• If you wanted to separate network segments in a LAN, it would require additional routers, cables, and switches

• VLAN reduces hardware requirements by allowing different logical networks to share same physical hardware

How VLANs work

• Operate at layer 2 of the osi model

• Switches tag each data frame with a VLAN identifier (ID) as it passes through, defining its VLAN

• Tags: used to determine the path of frames, ensuring they stay within their VLAN

Reasons for using VLANs

• Stronger security

  Keeps sensitive data isolates to limit exposure and reduce the risk of breaches

• Better performance

  Shrinks broadcast domains to minimize excess network traffic

• Simplified Management

  makes it easier to apply policies and troubleshoot network issues

• cost savings

  Maximizes use of current hardware and minimizes the need for additional equipment

VLAN Database

• Hold VLAN configuration settings used by switches including:

  identifier

  name

  MTU size

• Cisco Switch

  VLAN.DAT: Helps maintain consistent VLAN settings, allows for easier configuration and deployment across the network

Switch Virtual Interface (SVI)

• A virtual layer 3 interface on a switch that enables communications for VLANs

• enables inter-VLAN routing without requiring an external router

• improves network efficiency by reducing the need for extra routing hardware