Discusses wireless LAN topologies from a high-level perspective (Part I)
It is more than evident that the wired networks are much different than the wireless networks. In the case of wireless networks there are different topologies that are available. The various topologies that can exist in wireless networks are:
Various Wireless Topologies
These are also known as piconet. For wirelessly connecting things that are very close to you the WPAN networks can be used. Example of things very close can be a mouse, a Bluetooth, a headset and other things that you want around yourself. Characteristics of a WPAN are -
Range: About 20 feet.
No. of Devices: Eight
Frequency: Unlicensed 2.4-GHz spectrum
The most common WPAN device is the Bluetooth. Looking at the number of people that have Bluetooth devices one should expect a huge amount of disturbance, which actually is not the case. This happens because Bluetooth uses Frequency Hopping Spread Spectrum (FHSS). A Bluetooth piconet can have many devices out of which only 8 can be active. Falling under the 2.4 GHz spectrum, these are standardized by 802.15 standards.
These are designed for areas that are bigger than that covered under WPAN. These can perform ideally in small to large offices. The equipment is generally owned and managed by the enterprise in which this network exists. Its characteristics are:
Range: About 100 meters between the client and AP.
Frequency: 2.4 GHz or 5 GHZ spectrum
No. of Devices: More than eight
For covering a larger distance, more power is required and these networks are not personal in nature. Unlike WPAN networks, WLANs are flexible. The first protocol to be used for WLAN was 802.11b, but now 802.11a, 802.11b and 802.11g are being used. WLAN networks are designed for mobile clients and for this very reason there are multiple users on them. Print and presentation servers along with storage devices can also be found on WLANs.
The term WMAN network stands for a wireless metropolitan-area network (WMAN). These networks cover large geographic areas. The characteristics of these networks are:
- The speed of these networks is indirectly related to the distance.
- The speeds is close to the speed of broadband as compared to the Ethernet.
- In both point-to-point, or point-to-multipoint these networks are used as a backbone.
The best example of WMAN networks is WiMax which is used as an alternative to broadband services like DSL and cable. WMAN networks at times can use unlicensed frequencies but this is not always preferred for the reason that interference may be caused due to others using the same frequency. Using of licensed frequency incurs costs.
The acronym WWMAN stands for wireless wide-area network (WWAN). These are ideal where coverage is being sought over large geographic areas. The characteristics of these networks are:
- Low data rates
- One has to pay for using them
- It involves high cost of deployment
These are usually expensive. A cellular service is an example of WWAN network. These offer data as well as voice access. Data rates hover around 115 kbps, while higher data rates may be provided by some service providers.