WiFi top ten common misunderstanding summary

(Author: Mike Leibovitz)

WiFi is increasingly becoming the preferred mode of global Internet connectivity. According to information published by the blog site Gigaom, by 2020, there will be 24 billion devices connected to the Internet. Most devices will use the wireless way to access the Internet. Although more and more people know about WiFi, how it actually works is not known to most people. Even in the IT expert circle, certain facts about WiFi networks are often misunderstood. Here are some of the top ten common misconceptions about WiFi in the industry.

Shared media

The radio signal is programmed at each access point (AP) to operate on a single channel. Within this single channel, multiple clients can connect and communicate. All clients using it share this single channel medium.

However, the fundamental problem with radio systems is that a wireless station cannot listen while transmitting, and therefore cannot detect collisions. With this in mind, developers of the 802.11 specification have created a collision avoidance mechanism called Distributed Control Function (DCF). According to the DCF, a WiFi station only transmits when it believes that the channel is clear. As a result, the probability of collisions increases with increasing traffic or when the mobile stations cannot "hear" each other. Although there are some protocols for controlling operations, WiFi is similar to the Layer 2 HUB technology of traditional wired networks.

2.802.11b and traditional protocols "slow down" media

The result of having the old protocol run in the same environment is to "slow down" all other clients. In fact, traditional customers need to spend more session time sending the same amount of data as new 802.11n or 802.11 ac clients. The call fairness algorithm proved to be effective in solving this problem.

3.L1/L2 802.11 function

It is widely believed that WiFi uses radio frequency (RF) technology and there is no physical wired connection between the sender and the receiver. When an RF current is supplied to the antenna, an electromagnetic field is created and then propagated through space. In fact, the 802.11 protocol is an L2 technology that uses the underlying L1 of the OSI stack to perform its duties. The communication between the client and the access point is connected in the air. Over-the-air communication is handled by L2 QoS based on the 802.11e standard.

4.Downstream and Upstream

There is a significant difference between the downstream from the access point to the client and the upstream from the client to the access point. Currently, most WiFi over-the-air technologies only offer downstream enhancements.

5. Uplink rate and downlink rate

The only rate that is generally accepted by the industry is the transmission rate. However, the asymmetric rate is typical, and the transmission rate seen at our connectable clients does not necessarily represent the reception rate. This is also confirmed in terms of access points and infrastructure, which demonstrates a separate uplink rate Tx and downlink rate Rx in the WiFi world.

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