Wlan: what is it, definition, 802.11 standard and differences with lan

What is a WLAN

WLAN stands for Wireless Local Area network, that is, wireless local area network, this being the main difference with a local area network or LAN. In it what we have is a data exchange network between computers but that is done through electromagnetic waves through the air, if a physical medium.

The essence of a WLAN is to create a local area network with a certain number of devices that will connect directly to a router or an access point. At no time should we talk about WLAN to refer to the connection between smartphones with the GSM, 3G, 4G or 5G coverage network, since in this case we would rather be talking about a WWAN at least.

A WLAN will provide access to the Internet like any other internal network through a router, and exactly like a LAN, through a gateway protected with a better or worse firewall, which ultimately isolates the internal network from the Internet.

But we can also create a WLAN with our own Smartphone, since currently smartphones have an access point function, this is called WiFi Direct. Being able to supply a certain range of Wi-Fi coverage to other computers even assigning an IP address automatically. Through the terminal we can access the Internet as if it were a router.

WMAN and WWAN

Just as there are MANs and WANs in terms of Ethernet and wired networks, there are also Metropolitan Area Wireless Networks and Wide Area Wireless Networks.

A WMAN includes that network that extends approximately in a metropolitan area such as a medium / large city. A WMAN can be for example WiMAX technology, a means of wide coverage that provides a connection through microwaves for rural areas, or areas where ADSL fiber or anything else does not reach. There are other variants not specifically WiMAX that can be considered WMAN.

And finally a WWAN as it will be a wide area wireless network, which can occupy a country or the entire world. Surely you all imagine what network can be of this type, effectively the GSM, 3G, 4G and 5G network will be WWAN.

Obviously in these cases we are not talking about internal networks, not at least as long as we do not use VPN connections or virtual private network. In this case, the computers connected to a WWAN or WMAN will not be able to see each other, due to having public IP addresses and making their access through a 4G, 5G modem or the version in which it operates.

Differences with an 802.11 vs 802.3 LAN

While a WLAN does not use a physical means to connect the hosts to its internal network, a LAN network uses a cable, usually stranded or fiber optic, to make connections between the router and computers.

It will be the same router that supplies the IP addresses to the hosts and will allow the wireless devices to "see" each other on the internal network.

Another important difference lies in the standard that defines each type of connection. In the case of LAN we talk about IEEE 802.3x and its variants (x), while in WLAN we must refer to IEEE 802.11x also with its variants. This causes for example that the frames (packets) are different due to the type of transmission medium.

The frame according to the Ethernet 802.3 standard consists of a maximum size of 1, 542 bytes, supporting a maximum load of 1, 500 bytes for data. In the case of 802.11 the frame will have a normal extension of 2346 bytes since the MAC address is much more complex to add more security. We will see it graphically:

Address 1 (SA): It is the MAC address of the sender Address 2 (DA): MAC address of the final receiver or destination Address 3 (TA): It is the MAC address of the medium that transmits the frame to the medium Address 4 (RA): This is the MAC address intended to receive the incoming transmission from the TA medium.

In both cases we are talking about the frames that belong to layer 1 or physical medium and layer 2 in data link of the OSI model using the CSMA / CD protocol for Ethernet and CSMA / CA for Wi-Fi.

Can a LAN connect to a WLAN?

There is no impediment for a WLAN and a LAN to connect, in fact they are part of the same internal network unless we decide not to. In principle, a Wi-Fi router supplies the same IP addresses in LAN as in WLAN, with the same subnet mask and on exactly the same network. Therefore, we can share files without problems between a wired PC and a Wi-Fi laptop, being able to do exactly the same functions.

The exact same thing happens in the case of a Wi-Fi access point or a Mesh network. In short, they are devices that extend wireless coverage, so the IP allocation corresponds to the same network and communication would not be cut either.

This will be different, for example, with a guest WiFi network, which, even supplying the same IP address, will be the router itself that limits the access of these users to the rest of the internal network.

IEEE 802.11 classes of standards for WLAN

WMAN and WWLAN is very good, but we consider that it is not an issue to be discussed here, since we are focusing on wireless networks at the local level.

Then it will be important to know the different versions of the standard or name IEEE 802.11 in order to know the speeds and characteristics that each version provides. What will be currently operating on our devices? Well we will find out now.

IEEE 802.11a / b / g

These standards are considered channel and frequency identifiers through which the hosts will connect to the WLAN.

With 802.11a, it operates on the 5 GHz to 20 MHz and 2.4 GHz bands, the two most used in Wi-Fi, at least in the European area. In addition, in this area it operates together with 802.11h, which makes certain modifications in the dynamic control of frequencies and transmission powers so that there are no interferences with satellite signals and radar systems.

802.11 b and g are operating only in the 2.4 GHz band, providing it with 11 channels for WiFi, of which 1, 6 and 11 are normally used. In this band, it operates at a frequency of 25 MHz as bandwidth. The transmission speed in version "b" is 54 Mbps without OFDM sending capacity implemented in the latest available version.

IEEE 802.11n

This version of the standard began operating in 2008 although it was defined in 2004. The speed is 600 Mbps in connections of a maximum of 3 × 3 (3 antennas). It simultaneously uses the 2.4 GHz and 5 GHz bands. It was the first to implement MIMO (Multiple Input - Multiple Output) technology that allows multiple channels to be used at the same time for sending and receiving data with up to 3 antennas.

We have not yet reached speed rates comparable to LAN cabling, but being able to use both frequencies with the same wireless point, all to devices with great coverage.

IEEE 802.11ac

It is also called WiFi 5 and it was implemented in 2014 and today most devices work on this version. In this case it is a version that only operates in the 5 GHz band to provide speeds of 433 Mbps in connections with an antenna (1 × 1) and up to 1.3 Gbps in 3 × 3. Its maximum transfer will be 3.39 Gbps using 4 antennas at a frequency of 160 MHz or 6.77 Gbps with 8 antennas.

This standard implements MU-MIMO technology with up to 8 data streams with bandwidths of up to 160 MHz and 256 QAM. It normally operates in conjunction with 802.11n for devices using the 2.4 GHz band.

IEEE 802.11ax

This is the new version also called WiFi 6 and 6th generation WiFi implemented in 2019 and that many teams already have support thanks to the new hardware. In addition to MU-MIMO, new OFDMA technology is introduced that improves network spectral efficiency for WLANs where large numbers of users are connected. Therefore, it is a standard that above all increases its performance with large client loads and simultaneous transmissions.

It operates on the 2.4 GHz and 5 GHz frequencies, and supports 4 × 4 and 8 × 8 connections in both cases. The transmission speed increases to 11 Gbps with the frequency of 160 MHz and 1024QAM.

Conclusions and more network tutorials

Operating over a WLAN is not an impediment to having our own internal network safe and with enormous speeds as we have seen especially in the 802.11ac and 802.11ax versions. With encryption on connections thanks to WPA and WPA2-PSK it is even more secure than a wired network.

In addition, both LAN and WLAN are compatible and operate on the same data exchange network. Everything will depend on the configuration of our router and its capacity. Now we leave you with some tutorials related to the topic:

What IEEE version do your devices use? Do you have shared files on LAN and WLAN?