Wireless Distribution System for 802.11

If you would like to extend the coverage of your WiFi network, you could apply the Wireless Distribution System (WDS) bridging feature that could be found in most of the WiFi chipset. I have connected two Access Point (AP) using WDS to extend the coverage of the network. 1st AP contains single wireless adapter and one Ethernet adapter. Another AP consists of dual wireless adapters. The 802.1d Ethernet Bridging kernel feature is enabled in the kernel while the bridge utilities is installed. The WDS feature must be enabled in both AP so that 4 address format used in 802.11 header can be handled.

[LAN] ---- AP1 ----- [WiFi] ---- AP2 ---- [WiFi]

Here, part of the commands for enabling the bridging between two different interfaces:
# brctl addbr br0
# brctl addif br0 ath0
# brctl addif br0 ath1
# ifconfig br0

As usual, extending the network comes with the price of increased latency and decreased throughput. 802.11 header overhead is increased by adding two additional MAC addresses. The following MAC addresses are needed to ensure the success delivery of 802.11 frame crossing two different APs:
- MAC for the sender
- MAC for the final destination
- MAC for the sending AP
- MAC for the receiving AP

[AP1]
Ping statistics for 172.16.6.1:
Packets: Sent = 9, Received = 9, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 2ms, Maximum = 3ms, Average = 2ms

[AP2]
Ping statistics for 172.16.6.1:
Packets: Sent = 9, Received = 9, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 2ms, Maximum = 5ms, Average = 3ms

Try it out if you could have two WiFi cards in your PC.