Wireless Networks

Wireless LANs can be implemented internally or externally. Internal wireless LANs are generally used as an alternative to structured cabling systems. They are particularly desirable in areas where mobility is a requirement. For instance this could be a hospital ward, where a doctor uses a laptop to access patient records as he moves from bed to bed. In such a situation it would be impossible to use a cabled system. Internal wireless LANs consist of Access Points which act as a bridge between the wireless network and the fixed LAN and wireless client cards which connect the user to the wireless network. The client cards are fitted into PCs or laptops and connect via wireless to the Access Point, which in turn connects them to the fixed network.

PlanNet21 is a Cisco Advanced Wireless LAN specialized partner. As a wireless LAN partner, PlanNet21 engineers have been trained and certified in the installation and configuration of the Cisco range of wireless LAN products. The engineers at PlanNet21 have designed and installed numerous wireless networks based on the Cisco range of products. Cisco Wireless products can be used for both voice and data connectivity.

The initial step to any wireless rollout is to perform a site survey. This identifies the optimum locations for placement of access points. PlanNet21 can perform the site survey and based on the results design the wireless network that best fits the client's requirements. We can then provide the equipment and install the system for the client. PlanNet21 will fully test the system before putting it into production for the client.

Wireless Standards
802.11b

IEEE 802.11b operates in the 2.4 GHz unlicensed ISM band. 802.11b became a standard in September 1999. It defines Direct Sequence Spread Spectrum (DSSS) RF technology operating at data rates of up to 11 Mbps. Because IEEE 802.11b is a standard, products from different vendors can interoperate together.

802.11a

802.11a uses the less congested 5 GHz band which avoids potential interference from cordless phones and microwaves. 802.11a is not interoperable with 802.11b unless you are using equipment that implements both standards. 802.11a uses orthogonal frequency-division multiplexing (OFDM) and supports data rates up to 54 Mbps.

802.11g

In 2003, a third wireless standard called 802.11g was introduced. 802.11g works in the 2.4 GHz band but uses orthogonal frequency-division multiplexing (OFDM) to obtain higher data speeds. The 802.11g specification offers speeds of up to 54 Mbps. 802.11g hardware is compatible with 802.11b hardware, however with an 802.11b device in the network your speed will drop dramatically.

802.11n

802.11n was finally ratified in 2009. The new specification adds technology called multiple-input multiple-output (MIMO), a signal processing and smart antenna technique for transmitting multiple data streams through multiple antennas. This allows 802.11n to achieve maximum data speeds of approximately 200 Mbps, delivering bandwidth ideally suited for video streaming. 802.11n is compatible with previous generation 802.11a/b/g, but speed and performance will drop if an 802.11a/b/g device joins the network.