Ten Common Misconceptions About Wifi (1)
WiFi is increasingly becoming the preferred mode of internet connection worldwide. According to information published by blog site Gigaom, by 2020, there will be 24 billion devices connected to the Internet. The vast majority of devices will use wireless access to the Internet. While more and more people are aware of WiFi, how it actually works is not. Even in IT expert circles, certain facts about WiFi networks are often misunderstood. Here are ten common misconceptions about WiFi in the industry.
1. Shared Medium
The radio signal is programmed to operate on a single channel at each access point (AP). Within this single channel, multiple clients can connect and communicate. All clients using it share this single channel medium.
The fundamental problem with radio systems, however, is that a radio station cannot listen while transmitting and, therefore, cannot detect a collision. With this in mind, the developers of the 802.11 specification created a collision avoidance mechanism called the Distributed Control Function (DCF). According to DCF, a WiFi station only transmits when it thinks the channel is clear. In this way, the probability of a collision will only increase as traffic increases or if 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 legacy protocols "slow down" the medium
The consequence of having the old protocol running in the same environment is that all other clients will be "slower". In fact, legacy clients take more session time to send the same amount of data as new 802.11n or 802.11ac clients. The call fairness algorithm is proven to be effective in solving this problem.
3. 802.11 function of L1/L2
It is widely believed that WiFi uses radio frequency (RF) technology and there is no physical wired connection between sender and receiver. When an RF current is supplied to the antenna, an electromagnetic field is created, which is then able to propagate through space. In fact, the 802.11 protocol is an L2 technology that utilizes the underlying L1 of the OSI stack to perform its duties. Communication between the client and the access point is connected over the air. Over-the-air communication is handled via 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 provide downstream enhancements.
