The term "walled garden" is used in the context of Wi-Fi hotspots to refer to those web URLs that a user can access without being required to login or to pay for service. For example, the San Francisco International Airport may provide Internet access for the traveling public. A traveler turns on their wireless notebook computer and connects to the airport's network. They then may have the option of viewing the airports web site for terminal maps or flight information at www.flysfo.com, checking the weather at www.weather.com, and viewing local city information at www.sfvisitor.org. They may also log in to one or more subscriber services to access the rest of the Internet, check their email, or connect to their corporate network through the Internet. Without logging in the user can only access the three URLs allowed by the airport. These three URLs comprise the "walled garden" in which the user can browse without logging in. Controlling a user's access, and restricting them to a walled garden, is the job of a hotspot gateway, the piece of equipment that manages the link between the wireless users and the Internet.

Although some definitions of terms such as LAN, MAN, and WAN, depend on the geographical area covered by the network, we prefer a definition that also takes into account the technology used. In general, a WAN (Wide Area Network) covers an area larger than a single city. WAN links are typically point-to-point in nature, although more than one logical WAN link commonly shares a single physical trunk. WAN links may be formed between two buildings in the same city, or between two cities at different places on the globe. WAN technologies include Frame Relay and ATM.

WDS - See "Wireless Distribution System"

WEP is the encryption and authentication method that is specified in the original 802.11 standard. WEP defines an encryption method based on the RC4 stream cipher, in which an algorithm creates a pseudo-random bit-string (known as the keystream ), equal in length to the data that is to be encrypted (known as the plaintext ), and then the plaintext is mathematically combined (XOR'ed) with the keystream to produce the encrypted data (known as the ciphertext ). 

On-line at www.Wi-Fi.org, the Wireless Fidelity Alliance (Wi-Fi) is a nonprofit international association formed in 1999 to certify interoperability of wireless products based on the IEEE 802.11 specification. The term "Wi-Fi" originally referred specifically to 802.11b equipment but the use of the term has been broadened to include any 802.11 equipment (802.11a, b, and g). A "Wi-Fi network", then, is a wireless network consisting of equipment that meets the 802.11 networking standards.

An industry consortium called the Wireless Fidelity Alliance tests equipment to confirm that it complies with the applicable 802.11 standards. Originally, such equipment was said to be certified by the "Wi-Fi Alliance". This was shortened, in common usage, to simply be "Wi-Fi equipment". As time went on the use of the hyphen in the acronym was not used consistently and "WiFi" came to be a common term for equipment and the 802.11 standards in general. If you do a web search for "Wi-Fi" and "WiFi" (including the quotes to force the search to return only specific results) you'll see that both forms are used throughout the Web.

"Worldwide Interoperability of Microwave Access" The term "WiMAX" refers to communication using the IEEE 802.16 standard. Saying "Wi-MAX" instead of "802.16" is like saying "Wi-Fi" instead of saying "802.11". WiMAX is a standards-based wireless technology that provides high-throughput broadband connections over long distances. WiMAX can be used for a number of applications, including "last mile" broadband connections, hotspot and cellular backhaul, and high-speed enterprise connectivity for businesses. An implementation of the IEEE 802.16 standard, WiMAX provides metropolitan area network connectivity at speeds of up to 75 Mb/sec. WiMAX systems can be used to transmit signal as far as 30 miles. However, on the average a WiMAX base-station installation will likely cover between three to five miles. 

The term distribution system in this context refers specifically to the interconnection of 802.11 access points. They are said to communicate to each other over the distribution system" In most cases it's a wired distribution system that's in view since most wireless networks use access points that are interconnected over the in-building Ethernet network.. The access points in a typical Wi-Fi network are star-wired back to one or more Ethernet switches. Ethernet forms a wired distribution system. When access points communicate to each other directly over the air it's referred to as a wireless distribution system. One could say, then, that there are Wi-Fi client services (where client computers associate to, and communicate through, access points and there are distribution services (where access points send data directly to one-another).

WDS links between two end-points are called Point-to-Point links. WDS links can be set up whereby a central access point communicates to multiple other access points (placed in a circle, more or less, with a radius somewhere between 1000-feet and 2-miles from the center). This is called a Point-to-MultiPoint topology. It's important to recognize that many of the descriptions of WDS networks sound strikingly similar to those that would be heard concerning wireless mesh routing. The two technologies do produce a somewhat similar end result, but WDS involves a static pre-configuration of the system with no fault-tolerance and potentially severe bandwidth restrictions. The benefit of WDS is in its simplicity and the resulting significantly lower cost of WDS when compared with mesh routing. We could say, "You get what you pay for" but we would have to temper that with "Don't pay for something you don't need!" Sometimes WDS provides the most cost-effective solution to an interconnection problem. If you're connecting two buildings with a point-to-point connection, WDS is often the best solution. When you've got a campus environment, with multiple buildings requiring interconnections, you have to weigh the capabilities of WDS versus a wireless mesh routing implementation. You may read the mesh routing encyclopedia entry for more details.

There are several topologies and configurations for WDS implementations:

WDS is not a replacement for wireless mesh routing, and wireless mesh routing is not a replacement for WDS. Mesh routing provides higher bandwidth, auto-discovery, and redundancy in the event of a radio failure or communication link interruption. It's a matter of assessing the value proposition to see if your application demands the mesh routing capabilities that WDS does not possess.