Wireless Repeaters or Extenders
Wireless repeater or extender is a device that receives the Wi-Fi signal from the Wi-Fi enabled Router/Gateway, and retransmits it. On the far end, the repeater receives the Wi-Fi signal from the mobile client(s) and retransmits the signal back to the Wi-Fi enabled Router/Gateway.
Note: Wi-Fi by its nature is half-duplex, which means the single channel is used for both Transmit and Receive, however both cannot occur simultaneously.
When a Repeater is introduced into the network, transmissions will double and delays are potentially introduced. This occurs due to the nature of the repeaters catch and forward design. In other words, for every packet it receives, the repeater must process it, and then forward it out its internal transmitter. This has the effect of cutting the performances in half for traffic going through the repeater. Depending upon the nature of the application, this may or may not be an issue and is considered to be a better alternative than providing no connectivity at all.
Depending upon the capabilities of the repeater, it can use the same Service Set Identifier (SSID) or a different SSID. The SSID is the name that uniquely identifies one Wi-Fi network from any neighboring networks. The SSID allows users to control what network they want to connect to.
Both Single and multiple SSID deployments are supported with the following differences:
The illustration below shows how the overlapping Wi-Fi devices work together.
There are many varieties of Wi-Fi repeater and extenders available however they all are designed to support the basic repeater function. As an alternative to wireless repeaters, there are devices with the ability to support additional wired interfaces such as:
These higher end devices are used to inter-connect hardwired devices and backhaul the traffic to the Wi-Fi enabled router/gateway over a Wi-Fi channel. These higher end repeaters or extenders closely resemble WAPs/Routers and are available in a similar price range.