Wireless Networking (220-901)

802.11a

802.11a is in the 5GHz range and runs at 54Mbps. A bad thing about 802.11a is that its range is very small.

802.11ac

802.11ac is a natural expansion of the 802.11n standard, incorporating even more streams, wider bandwidth, and higher speed. To avoid density issues in the 2.4GHz band, 802.11ac only used the 5GHz band. The latest versions of 802.11ac include a new version of MIMO called Multiuser MIMO (MU-MIMO). MU-MIMO gives a WAP the ability to broadcast multiple users simultaneously. Like 802.11n, 802.11ac supports dual-band operation.

802.11ad

802.11ad operated in the 60GHz band and has a theoretical limit of 7Gbps. The 60GHz band makes it difficult for other devices to interfere with devices on the network. The only downside is the short range the standard provides.

802.11b

802.11b is in the 2.4GHz range and runs at 11Mbps. It has a larger range than 802.11a, it is just slower. A bad thing about 802.11b is it being in the 2.4GHz range. This range is a popular frequency used by alot of electronic devices so you could get some interference. It is also backwards compatible with 802.11g.

802.11g

802.11g is in the 2.4GHz range and runs at 54Mbps. This standards has a larger range than 802.11a and is faster than 802.11b. But it does run in the 2.4GHz range so you can expect some interference. It is also backwards compatible with 802.11b.

Ad Hoc Mode

Ad hoc mode is sometimes called peer-to-peer mode because the two nodes are in direct contact with each other. Two or more wireless nodes communicating in ad hoc mode form what's called an Independent Basic Service Set (IBSS). Ad hoc mode networks are suited for small groups of computers (less than a dozen or so) that need to transfer files or share printers. Ad hoc mode networks are also good for temporary networks such as study group or business meetings

Bluetooth

Bluetooth wireless technology is designed to create a small wireless networks preconfigured to do very specific jobs. Some great examples of Bluetooth are radio, headsets, etc. Bluetooth is also used alot in personal are networks (PANs), PANs are small networks that use little devices. An example of this is connecting your smartphone to your wireless radio in your car. Bluetooth has been upgraded over the years. Bluetooth 1.1 and 1.2 supported speeds around 1 Mbps. Bluetooth 2.0 and 2.1 supported 3 Mbps and was backwards compatible. Bluetooth 3.0 tops out at 24 Mbps but this is accomplished by using an 802.11 connection. Bluetooth is in the 2.4GH range and uses 128 bit encryption. Bluetooth is also very resistant to interference. Class 1 Bluetooth tops out at 100 meters Class 2 Bluetooth tops out at 10 meters Class 3 Bluetooth tops out at 1 meter Bluetooth hardware comes built in on the hardware or you can get an expansion card to give you the bluetooth capabilities.

Infrared Wireless Networking

Communication through infrared devices is implemented via the Infrared Data Association (IrDA) protocol. The IrDA protocol stack is a widely supported industry standard and has been included in all versions of Windows since Windows 95. In speed and range, infrared isn't impressive at all. Infrared devices are capable of transferring data up to 4 Mbps. The maximum distance between infrared devices is 1 meter. Infrared links are direct line of sight and are susceptible to interference. So if something comes between you and the device you are connecting to it will break the connection. Infrared is designed to make a point to point connection between two devices only in ad hoc mode. No infrastructure mode is available. Infrared is half duplex and is obviously only good for small data transfers, sharing a file.

802.11n

The 802.11n standard brought several improvements to Wi-Fi networking, faster speeds and longer ranges. The 802.11 specification requires all but hand-held devices to use multiple antennas to implement a feature called multiple in/multiple out (MIMO), which enables the devices to make simultaneous connections. With up to four antennas, 802.11n devices can achieve amazing speeds. 802.11n also has a feature called dual band. In dual band, your AP can simultaneously run 2.4GHz and 5GHz simultaneously; some support 802.11a devices as well as 802.11b/g devices.

IEEE 802.11-Based Wireless Networking

The IEEE 802.11 wireless Ethernet standard, more commonly known as Wi-Fi, defines methods devices may use to communicate via spread-spectrum radio waves. The 802.11-based wireless technologies broadcast and receive on one of two radio bands: 2.4GHz and 5GHz. A band is a contiguous range of frequencies that is usually divided up into discrete slices called channels. Over the years, the original 802.11 standard has been extended to 802.11a, 802.11b, 802.11g, 802.11n, and 802.11ac variations used in Wi-Fi wireless networks. Each of these versions of 802.11 uses on of the two bands, with the exception of 802.11n, which uses one or may use both. Newer wireless devices typically provide backwards compatibility with older wireless devices. If you are using a 802.11n WAP, all of your 802.11g devices can use it.

Wireless

To extend the capabilities of a wireless Ethernet network you need a wireless access point (WAP). A WAP centrally connects wireless network nodes in the same way that a hub connects wired Ethernet PCs. Many WAPs also act as switches and Internet routers. Like any other electrical device, most WAPs draw their power from a wall outlet. More advanced WAPs, especially those used in a corporate environment, can also use Power over Ethernet (PoE). Using PoE, you only need to plug a single Ethernet cable into the WAP to provide both power and a network connection. Bluetooth comes in as a built in option in many PCs and devices today.

Wireless Networking Standards

Today's wireless world is dominated by radio frequency (RF) technologies, in particular the 802.11 (Wi-Fi) standards. Other standards, such as infrared, Bluetooth, and cellular, hold a strong place in today's market as well.

Other Wireless Standards

Wi-Fi does dominate the wireless networking market, but there is also standards that are great for smaller networks (two computer small). A lot of smaller networks use Bluetooth or infrared to connect devices. Mobile devices, such as smartphones, wearables, and tablets, connect wirelessly via cellular networks.

Wireless Networking Software

Wireless devices use the same networking protocols and client that their counterparts use, and they operate by using the carrier sense multiple access/collision avoidance (CSMA/CA) networking scheme.

Speed and Range Issues

Wireless networking data throughput speeds depend on several factors. Foremost is the standard that the wireless devices use. Another factor is the distance between wireless nodes. There are also dead spots, which are areas that completely block out the signal between the two devices.

Infrastructure Mode

Wireless networks running in infrastructure mode use one or more WAPs to connect the wireless networks nodes to a wired network segment. A single WAP servicing a given area is called a Basic Service Set (BSS). This service area can be extended by adding more WAPs. This is called an Extended Basic Service Set (EBSS). Wireless networks running in infrastructure mode require more planning and are more complicated to configure than ad hoc networks.