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Introduction to Wireless LANs in Computer Networks

wireless lans in computer networks

In this blog, you will get introduced to the concept of wireless networks, especially Wireless Local Area Networks (LANs) using Wi-Fi. We will cover all the fundamentals of  wireless LANs in Computer Networks in this blog.

Note: If you haven’t read the previous blog of our CCNA 200-301 series, I highly recommend you do so. 

Make sure that you stick to the end to clear all your concepts about the Wireless LANs in Computer Networks. You must know that there are two types of network technologies:

  • Local Area Networks (LANs)
  • Wide Area Networks (WANs)

The networks that connect devices in a small geographical area such as a room, building, etc are referred to as Local Area Networks (WANs). Further, the LANs are of two types:

  • Wired LANs:

It is a mixture of copper and fiber-optic cables to connect nodes. It is also known as Ethernet LAN.

  • Wireless LANs:

As the name suggests, wireless LANs do not use fiber-optic cables. They use radio signals to connect nodes instead of cables and wires.

Now that you know what’s the difference between wired and wireless LANs, let’s begin learning about wireless LANs in detail!

What are Wireless LANs in Computer Networks?

A wireless network is a type of computer network that does not require wires or cables to connect the user to the network. It is rather a wireless network that connects the nodes. 

In a wireless LAN, an access point (AP) present over a Local Area Network connects other wireless devices to your device.

wireless network

You must already be familiar with the term Wi-Fi. Do you know that according to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards, wireless connections are often called Wi-Fi?

Yes, it is true! Therefore, the terms wireless LANs and Wi-Fi are often used interchangeably with each other. Nowadays, there are so many versions of the standardized Wireless LANs that use the same standard number 802.11 followed by small case alphabets such as 802.11c.

How Do Wireless LANs work?

As wireless LANs do not have fiber optics or cables to communicate over a LAN, they send wireless signals to the network using electromagnetic waves or Radio Frequencies.

  • The sender applies an alternating current to an antenna to send the wireless signals.
  • This, in turn, generates electromagnetic fields that are spread out as waves.
  • In the electromagnetic spectrum, the radio frequency range is from 30 Hz to 300 GHz which can be used for different purposes.
  • IEEE 802.11 wireless LANs use some chunks of ultra-high frequency and super-high frequency.
  • Wi-Fi uses two main frequency ranges:
    • 2.4 GHz band: It provides better penetration through walls and can travel long distances in space.
    • 5 GHz band
radio waves

In the above image, can you spot the radio waves?

What are the 802.11 Wireless Standards?

There are a number of 802.11 Wi-Fi standards. These standards use different frequencies and provide different data rates at different radio frequencies. 

To know about these 802.11 wireless standards, check out the table given below.

802.11 wireless standards
  • The original 802.11 came into existence in the year 1997.
  • The 802.11n is also called ‘Wi-Fi 4’.
  • The 802.11ac is also called ‘Wi-Fi 5’.
  • The brand new 802.11 ax was introduced in the year 2019. It is also known as ‘Wi-Fi 6’.

It is important that you remember the names of these 802.11 wireless standards and their respective frequency ranges as well as maximum data rates.

If you want to learn more about the functionalities of the various ranges of frequencies, check out this flowchart below. The image shows various frequency bands and where they can be used the best!

frequency bands

For example, you can check which Wi-Fi standards are supported by iPhone 11 and the later models.

iPhone 11 and later models

What are the Different Types of Service Sets?

802.11 covers different types of service sets which consist of groups of various wireless network devices.

There are three important types of service sets:

  • Independent service sets
  • Infrastructure service sets
  • Mesh service sets

Note: All the devices in the service sets belong to the same SSID (Service Set Identifier). An SSID identifies a service set. It is a human-readable name and is not always unique.

You can always change the SSID of your Wi-Fi/ wireless LAN to something readable such as Rohit’s Wi-Fi.

Now, let’s discuss different types of service sets.

1. Independent Basic Service Set (IBSS)

An Independent Basic service set (IBSS) is a wireless network that does not need Access Points (APs) to communicate with other computers wirelessly. It can connect two or more wireless devices directly.

  • IBSS is also known as Ad Hoc Networks.
  • IBSS can be used to transfer files. For example, sending photos via Bluetooth from your phone.
  • IBSS is usually used for limited services such as quick file transfers.
  • It is not scalable.

2. Basic Service Set (BSS)

A Basic Service Set (BSS) is a type of Infrastructure service set. BSS connects clients to each other through an Access Point. Remember that the clients are not connected directly to each other through this service set.

  • The Access Point is uniquely identified by a Basic Service ID (BSSID). It acts as the MAC address of the AP’s radio. You already know that MAC addresses are unique!
  • A request is sent by wireless devices to the AP to connect with the BSS.
  • These wireless devices are referred to as ‘clients’ or ‘stations’.
  • There is a defined physical area to which a BSS is limited. This area is called Basic Service Area (BSA). The signals cannot go beyond it.

Note: BSS1 and BSS2 are the two types of BSS. They together form an Extended Service Set (ESS). In this service set, APs present in the BSSs are connected by a wired network!

Extended Service Set

3. Mesh Basic Service Sets (MBSS)

Sometimes, it is difficult to run an Ethernet connection to every Access Point. In these situations, a Mesh Basic Service Set (MBSS) can be used.

An MBSS uses two radios:

  • A radio to provide a BSS to the wireless clients
  • Another radio to form a ‘backhaul network’. It is used to bridge traffic from one AP to another AP.

In an MBSS, at least one Access Point is connected to a wired network. This Access Point is called Root Access Point (RAP).

Note: A protocol is used to find the best path through the mesh in a similar way to how a routing protocol finds the best path to its destination.

Mesh Basic Service Sets (MBSS)

It’s a Wrap!

After reading this blog, you will know everything that you need to know about the fundamentals of a Wired LANs in Computer Networks. Who knew that Wired LANs are simply Wi-Fi?

Later on, we will dig deeper and learn about the different wireless architectures. Stay tuned for the upcoming blog of our CCNA 200-301 series.

Happy learning!

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