CCNA All in One

802.11ac The first thing to get out of the way is – like past Wi-Fi standards – 802.11ac is backwards compatible with 802.11b, g and n. This means you can buy an 802.11ac-equipped device and it will work just fine with your existing router. Similarly you can upgrade to an 802.11ac router and it will work happily with all your existing devices. That said you will need both an 802.11ac router and an 802.11ac device to enjoy the standard’s biggest benefits. And those begin with… 802.11ac Speed With any new wireless technology speed is always the headline-grabbing feature but, as with every wireless standard to date, the figures tossed around can be highly misleading. 1.3 gigabits per second (Gbps) is the speed most commonly cited as the 802.11ac standard. This translates to 166 megabytes per second (MBps) or 1331 megabits per second (Mbps). It is vastly quicker than the 450Mbit per second (0.45Gbps) headline speeds quoted on the highest performing 802.11n routers. So

802.11ac, the emerging standard from the IEEE, is like the movie  The Godfather Part II . It takes something great and makes it even better. 802.11ac is a faster and more scalable version of 802.11n. It couples the freedom of wireless with the capabilities of Gigabit Ethernet. Wireless LAN sites will see significant improvements in the number of clients supported by an access point (AP), a better experience for each client, and more available bandwidth for a higher number of parallel video streams. Even when the network is not fully loaded, users see a benefit: their file downloads and email sync happen at low‑lag gigabit speeds. Also, device battery life is extended, since the device’s Wi-Fi interface can wake up, exchange data with its AP, and then revert to dozing that much more quickly. 802.11ac achieves its raw speed increase by pushing on three different dimensions: ●     More channel bonding, increased from a maximum of 40 MHz with 802.11n up to 80 or even 160 MHz (for s

Nowadays there are three organizations influencing WLAN standards. They are: ITU-R  : is responsible for allocation of the RF bands IEEE  : specifies how RF is modulated to transfer data Wi-Fi Alliance  : improves the interoperability of wireless products among vendors But the most popular type of wireless LAN today is based on the IEEE 802.11 standard, which is known informally as Wi-Fi. * 802.11a: operates in the 5.7 GHz ISM band. Maximum transmission speed is 54Mbps and approximate wireless range is 25-75 feet indoors. * 802.11b: operates in the 2.4 GHz ISM band. Maximum transmission speed is 11Mbps and approximate wireless range is 100-200 feet indoors. * 802/11g: operates in the 2.4 GHz ISM band. Maximum transmission speed is 54Mbps and approximate wireless range is 100-200 feet indoors. * 802.11n: operates in the 2.4 GHz ISM band. Maximum transmission speed is 300Mbps and approximate wireless range is 100-200 feet indoors. ISM Band: The I