4.4 Wireless Topologies

With the advent of wireless networks come the challenges of making them work. As traditional wired networks evolved, so did the technologies that they were built upon. Both physically and logically, these "old school" networks began featuring more efficient, less expensive hardware and software for easier and more efficient physical and logical connections.

Since the early days, networking has come a long way. We are currently in the midst of a wireless revolution that has been highlighted by both office and home networks moving to wireless technologies. The reason for this transformation parallels the same reason for updating earlier networks from coax to cat 5 and cat 5 to fiber. Ultimately the profile of technology will reflect the new standards being developed. In the case of wireless networking there are several new areas to consider, including topologies. The following section will explain the newest wireless topologies that are being used as the foundation for wireless networking.


Infrastructure Mode vs. Ad Hoc Mode

Traditional wired networks can be implemented in one of two ways: either as a peer-to-peer network or as a client server network. Wireless networking features comparable profiles known as Infrastructure Mode and Ad-Hoc Mode.


Ad Hoc Mode is also referred to as an Independent Basic Service Set (IBSS).



Infrastructure mode, which is outlined in the 802.11 networking standard, is more common for office environments because sharing resources is usually a priority for these types of networks. An access point connected to a LAN allows the wireless nodes to securely access the LAN’s resources. The WAP basically serves the same function as a hub on a wired LAN.

Infrastructure Mode vs Ad-Hoc Mode

Generally speaking both Ad-Hoc and Infrastructure Mode wireless networks architectures have advantages and disadvantages.

 
Infrastructure Mode
Ad-Hoc Mode
TCO  
X
Security
 
Ease of Implementation  
X
Performance
X
 
Access
X
 
Management
X
 

Bridged Mode

Bridged Mode refers to a wireless networking solution that is implemented when a company wants to extend a wired LAN using WAPs.

To best explain bridged mode it is necessary to understand why it was developed.


Special antennas can be purchased to extend or modify the shape of the radio signal. For example, in bridged mode, antennas that can be focused directly at the WAP on the other building will be more useful than an omni-directional antenna that sends out a signal equally in all directions.

Repeater Mode

Repeater Mode is used to extend the range of a Wireless LAN.



Bridged Mode and Repeater mode are new developments in wireless technologies that enable communication between different segments of a wireless network. They are both useful extensions to the Infrastructure mode. It is important to realize that not all WAPs on the market support all modes. Make sure to check that the WAP being purchased will support the modes you wish to implement.