What is WDS

A Wireless Distribution System (WDS) Is A System That Enables The Wireless Interconnection Of Access Points In A Wireless Network Environment.

WDS allows a wireless network to be expanded using multiple access points without the need for a wired backbone to link them, as is traditionally required. The notable advantage of WDS over other solutions is that it preserves the MAC addresses of client packets across links between access points.

An access point can be either a main, relay or remote base station. A main base station is typically connected to the wired Ethernet. A relay base station relays data between remote base stations, wireless clients or other relay stations to either a main or another relay base station. A remote base station accepts connections from wireless clients and passes them on to relay or main stations. Connections between “clients” are made using MAC addresses rather than by specifying IP assignments.

All base stations in a Wireless Distribution System must be configured to use the same radio channel, method of encryption (none, WEP, or WPA) and encryption keys. They can be configured to different service set identifiers (SSID). Wireless Distribution System (WDS) also requires that every base station be configured to forward to others in the system.

WDS Point to Point Bridge

Wireless Distribution System (WDS) may also be referred to as repeater mode because it appears to bridge and accept wireless clients at the same time (unlike traditional bridging). It should be noted; however, that throughput in this method is halved for all clients connected wirelessly.

WDS Point to multipoint

With WDS, it allows you to build a completely wireless infrastructure because the network equipment no longer has to be connected to a wired LAN. Also, WDS features allow you to create large wireless networks by linking several wireless access points with WDS links. WDS is normally used in large, open areas where pulling wires is cost prohibitive, restricted or physically impossible.

WDS repeater

Wireless Bridge and Wireless Repeater

As shown in the above three pictures, WDS can be deployed in several configurations, point-to-point WDS Link; point-to-multipoint WDS Links; and WDS repeater.

Wireless Distribution System (WDS) can be used to provide two modes of wireless AP-to-AP connectivity:

• Wireless Bridging in which WDS APs communicate only with each other and don’t allow wireless clients or Stations (STA) to access them
• Wireless Repeating in which APs communicate with each other and with wireless STAs

Advantages

Two disadvantages to using Wireless Distribution System (WDS) are:

• The maximum wireless effective throughput is halved after the first retransmission (hop) that is made. For example, in the case of two routers connected via Wireless Distribution System (WDS), and communication is made between a computer that is plugged into router A and a laptop that is connected wirelessly using router B’s access point, the throughput is halved, because router B has to retransmit the information during the communication of the two sides. However, in the case of communications between a computer that is plugged into router A and a computer that is plugged into router B, the throughput is not halved since there is no need to retransmit the information.
• Dynamically assigned and rotated encryption keys are usually not supported in a Wireless Distribution System (WDS) connection. This means that dynamic Wi-Fi Protected Access (WPA) and other dynamic key assignment technology in most cases can not be used, though WPA using pre-shared keys is possible. This is due to the lack of standardization in this field, which may be resolved with the upcoming 802.11s standard. As a result only static WEP or WPA keys may be used in a WDS connection, including any STAs that associate to a WDS repeating AP.

There are many wireless access points available at the market today which have the capability of wireless distribution system (WDS) such as DAP-2590 D-Link; TRENDnet wireless 300N Access point; Cisco WP4400 Access point.

By Ki Grinsing