3.4 VLAN Basics Explained
Key Concepts
VLAN (Virtual Local Area Network) is a technology that segments a physical network into multiple logical networks. Key concepts include:
- VLAN ID: Unique identifier for each VLAN.
- Trunk Port: Port that carries traffic for multiple VLANs.
- Access Port: Port that belongs to a single VLAN.
- VLAN Tagging: Process of adding a VLAN tag to Ethernet frames.
VLAN ID
The VLAN ID is a unique number assigned to each VLAN. It helps in identifying and segregating traffic belonging to different VLANs. VLAN IDs range from 1 to 4094, with 1 being the default VLAN.
Example: In a school network, you might create a VLAN for students with ID 10, a VLAN for teachers with ID 20, and a VLAN for administrative staff with ID 30. Each VLAN ID ensures that traffic is isolated and managed separately.
Trunk Port
A trunk port is a network port that carries traffic for multiple VLANs. It is typically used to connect switches or routers and allows for the transmission of VLAN-tagged traffic. Trunk ports are essential for managing large networks with multiple VLANs.
Example: Suppose you have two switches in your network, each managing different VLANs. By configuring a trunk port between the two switches, you can ensure that traffic for all VLANs is transmitted efficiently without the need for multiple physical connections.
Access Port
An access port is a network port that belongs to a single VLAN. Devices connected to an access port are members of that specific VLAN and cannot communicate with devices in other VLANs unless routed.
Example: In a corporate office, each department might have its own VLAN. Computers in the HR department would be connected to an access port configured for the HR VLAN, ensuring that they can only communicate with other HR devices within the same VLAN.
VLAN Tagging
VLAN tagging is the process of adding a VLAN tag to Ethernet frames. This tag contains the VLAN ID, allowing network devices to identify and route traffic to the correct VLAN. VLAN tagging is essential for managing traffic in networks with multiple VLANs.
Example: When a device sends data to another device in a different VLAN, the switch adds a VLAN tag to the Ethernet frame. The receiving switch reads the VLAN tag and routes the frame to the appropriate VLAN, ensuring that traffic is isolated and managed correctly.
Understanding these VLAN basics is crucial for managing and optimizing network performance. By mastering these concepts, you can create a robust and flexible network infrastructure tailored to your specific needs.