What is VLAN (Virtual LAN)?

VLAN

A virtual local area network (VLAN) is a logical group of devices on a single physical network. Devices in a VLAN can communicate with each other as if they were on a single, local network, even if they are physically located on different parts of the network.

VLANs are created by adding configuration parameters to network devices, such as switches and routers. Once a VLAN is created, network devices that are configured for that VLAN can communicate with each other. 

Devices that are not configured for the VLAN cannot communicate with devices in that VLAN.

VLANs can be used to segment a network into different subnets for security or performance reasons. 

For example, a network administrator might create a VLAN for the accounting department that includes all of the devices in that department, such as computers, printers, and servers. 

The administrator can then configure security parameters that only allow devices on the accounting VLAN to communicate with each other, and not with devices on other VLANs. This prevents unauthorized access to the accounting department's network resources.

Advantages and Disadvantages of VLAN:

Advantage of VLAN

VLANs are useful because they:

• Isolate traffic. Devices in different VLANs cannot communicate with each other unless they have a router in between them. This can be used to segment traffic and improve security.
• Simplify network management. Devices in the same VLAN can be managed as a group, making it easier to add, remove, or move devices.
• Improve performance. Devices in different VLANs can be on different physical networks. This can improve performance because the traffic between VLANs does not have to travel through a router.

Disadvantages of VLAN:

Disadvantages of VLAN:

There are some disadvantages to using VLANs. For example, they can:

• Complicate the network. Adding VLANs can make the network more complex.
• Decrease performance. If a router is needed to communicate between VLANs, this can decrease performance.
• Increase costs. Adding hardware, such as routers and switches, can increase the costs of a network.

VLAN Protocols:

What is VLAN (Virtual LAN)

There are multiple VLAN protocols available, each with its own advantages and disadvantages. The most common VLAN protocols are 802.1Q, ISL, and PVST+.

802.1Q is the most widely used VLAN protocol, and is supported by most switches. It is a very simple protocol, which makes it easy to configure and manage. However, it does have some limitations, such as the maximum number of VLANs that can be created.

ISL is another popular VLAN protocol, which is supported by many Cisco switches. It is a more complex protocol than 802.1Q, but it provides more features and flexibility. However, it is not as widely supported as 802.1Q, and can be more difficult to configure.

PVST+ is a Cisco-proprietary VLAN protocol that provides enhanced features and performance. It is supported by most Cisco switches, but is not compatible with other brands of switches. PVST+ can be more difficult to configure than other VLAN protocols, but it provides the best performance and features.

What is VLAN tagging?

What is VLAN tagging

A VLAN tag is a small piece of information that is added to a data packet to identify which VLAN the packet belongs to. VLAN tags are used by switches to keep track of which packets belong to which VLANs, and to ensure that packets are only sent to the correct devices.

VLAN tags are added to data packets by network devices such as routers and switches. When a packet arrives at a device, the device looks at the VLAN tag to determine which VLAN the packet belongs to. The device then forwards the packet to the correct destination device or devices.

What is VLAN tagging

VLAN tags are used to improve network performance and security. By keeping track of which packets belong to which VLANs, devices can quickly and easily forward packets to the correct destination. This reduces the amount of time that packets spend travelling through the network, and improves overall network efficiency.

In addition, VLAN tags can be used to improve network security. By only forwarding packets to devices that are part of the correct VLAN, devices can help to prevent sensitive data from being leaked to unauthorized devices. This can help to protect the privacy of individuals and businesses, and to prevent data breaches.

How to Configure VLANs on Cisco Switch?

How to Configure VLANs on Cisco Switch?

To configure VLANs on a Cisco switch, you'll need to use the switch's command line interface (CLI). The process is relatively simple and can be done using the following steps:

1. Enter the switch's CLI by opening a terminal and typing in the switch's IP address.

2. Type (write) in the username and password.

3. Type in the command "enable" to enter enable mode.

4. Type command "configure terminal" to enter configuration mode.

5. Type in the command "VLAN [ID]" to create a new VLAN with the specified ID.

6. Type in the command "exit" to exit configuration mode.

7. Type in the command "write memory" to save the changes.

VLAN Troubleshooting:

VLAN troubleshooting:

There are a few things to keep in mind when troubleshooting VLANs. First, make sure that the switch ports are configured correctly. Each port should be configured with the correct VLAN ID. 

Secondly, check the switch configuration to make sure that the VLANs are configured correctly. The VLAN ID and the switch port assignment should match. 

Finally, make sure that the router is configured to route between the VLANs. The router should have a route for each VLAN that is configured on the switch.

Difference between VLAN and VPN:

VLANs (Virtual Local Area Networks) and VPNs (Virtual Private Networks) are both popular methods of creating isolated networks within a larger network.

VLANs create to dividing a physical N/W into logical segments. This allows each segment to be isolated from the others, which can be useful for security or performance reasons. VPNs, on the other hand, use encryption to create a private network that is tunneled through a public network (usually the Internet).

VPNs are often used to extend a private network across a public network, such as the Internet. This allows remote users to securely connect to the private network. VLANs, on the other hand, are typically used within a single physical network.

Another key difference is that VLANs can be controlled by software, while VPNs require special hardware or software at both ends of the connection. This makes VLANs much simpler to configure and manage.

Conclusion:

A VLAN is a group of networked computers which are separated from other networked computers by a switch or hub. 

A VLAN is usually based on the work of a company or organization. A VLAN is created by using the software that is sold with a switch, or by using the software that is sold with a router. 

It's very important to create a VLAN because it allows the different departments in a company to communicate on the same network without outside interference. 

This allows each department to communicate with each other without having to worry about someone else being able to see the information that's being shared. To learn more, you can contact us at ___.