Router Charts

Click for Router Charts

Router Ranker

Click for Router Ranker

NAS Charts

Click for NAS Charts

NAS Ranker

Click for NAS Ranker

More Tools

Click for More Tools

LAN & WAN How To

Introduction

What is a VLAN? Is it some sort of highly expensive technology or virtual reality? Not at all. VLANs are relatively simple, yet they offer a wide variety of options and capabilities to improve your network.

VLAN, or Virtual LAN, is a technology that enables dividing a physical network into logical segments at Layer 2. Functionally, VLANs enable a network administrator to partition a network into separate, independent networks. There are many reasons to separate a network into VLANs, and numerous options to consider.

While a useful technology for small LANS, VLANs are often deployed in large networks, too. In larger networks, VLANs are sometimes used to join physically separate LANs or LAN segments into a single logical LAN.

The goal of this article is to explain and discuss VLANs, including why you should consider using VLANs in a smaller network. I'll also walk through a configuration example showing how to configure a VLAN-aware switch to create separate LAN segments.

VLANs and Switches

If you have more than one device on your network, you probably have a switch. A switch is a simple device that operates at Layer 2 of the OSI model, forwarding data frames from one device to another based on their hardware or MAC (Media Access Control) address. The basic Layer 2 switch does not care or know about IP addresses, which operate at Layer 3.

Your switch may be a few ports built into your router, it may be a small unmanaged (non-configurable) switch such as the D-Link DGS-2205 shown in Figure 1. Or you may have a more advanced switch with VLAN capability, possibly referred to as a managed, "smart" or multilayer switch. Larger networks usually have multiple switches at numerous locations.

D-Link switch

Figure 1: D-Link switch without VLAN capability

As stated, switches pass data from one device to another based on their MAC addresses. The key question is, how does the switch know which MAC address is located on which port?

Even the simplest switch has a "learning ability" to read the MAC address of the devices connected, and store those MAC addresses in a table in memory. Switches "learn" by examining the source MAC address of every frame received. New MAC addresses learned on received frames are added to a table, creating in the switch's memory a mapping of MAC addresses to switch ports.

More LAN & WAN

Wi-Fi System Tools
Check out the new Wi-Fi System Charts, Ranker and Finder!

Featured Sponsors



Support Us!

If you like what we do and want to thank us, just buy something on Amazon. We'll get a small commission on anything you buy. Thanks!

Over In The Forums

How many powerline adapters can be in a home system? I seem to be running into a problem with my TP-Link adapters which seem to limit the number of ad...
I have an RT-AC5300 as the main node on the 2nd floor, an RT-AC3100 node on the 1st floor, and another RT-AC5300 as a node in the basement. The baseme...
Hey all, looking to replace my old n66 fork firmware router with a Asus 2900 tomorrow. Thoughts on what firmware to run? Leaning merlin Also is there ...
We we’re looking into setting up another VPN for our home business network. ExpressVPN was running way to slow. Anyone have any recommendations on top...
Routee dropped and one of the atennas came off. I tried to screw it back on the problem is the connecter Insude the router broke off. There are no scr...

Don't Miss These

  • 1
  • 2
  • 3