Guide to Optimize Advanced WiFi Settings – Maximize Range and Performance

  1. The following guide can be used to improve your WiFi performance by tweaking the advanced settings within your wireless router. You will need to connect to your Wireless Router's setup page using your Internet browser to be able to adjust these settings. Make sure you check your manufacturers guide to see how to connect to your particular Router's setup page and reach these settings.

  2. Advanced Settings:
    • Short vs. Long Preamble
    • ACK Timeouts
    • RTS Threshold and Fragmentation Threshold
    • DTIM and Beacon Interval
    • Afterburner

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  3. Short vs. Long Preamble
    Optimum Setting: Generally the best setting to use with modern WiFi Routers (e.g. 802.11g/n) in a home or business is to set everything to use Short Preamble. If you are still using any older 802.11b equipment, you should however use Long Preamble.

  4. How it works: Preambles are pauses that come before a wireless signal hits a networking device. This pause varies in length, the duration of which defines it as a long or short preamble. This data packet supplies the receiving device with the timing data each device needs for proper network synchronization. Following the preamble, the header supplies the receiving device with the broadcast type, speed and length of time it takes to complete the entire transmission of the data.

    • Long Preamble: Most wireless "b" devices are preset for long preambles. This allows increased compatibility between wireless devices, sometimes at the expense of speed. All wireless "b" devices must support long preambles, while short preambles are optional. The 802.11b protocol, for example, allows switching from a short preamble to long and back again to remedy difficulties in data transmission between devices.
    • Short Preamble: Newer wireless "b" devices using a short preamble typically experience quicker data transfers. Moving from a long to short preamble will not solve poor connection issues or slow Internet speeds. However, moving to wireless "g" and wireless "n" devices increases transfer speed and range. Short preambles work with every wireless type other than older types with limited transmission rates in the 1 to 2 Mbps range.

  5. ACK Timeouts
    Optimum Setting: Generally the best setting for indoor home or office use is 0 micro-second for the ACK. If any of the clients connected to a wireless router are operating at distances longer than 300 meters (about 1000 feet), please see the table below.

  6. How it works: ACK timeouts are used to an additional time-delay buffer to wireless transmissions at very long distances. For standard transmissions at short distances (e.g. those under 300m), almost no buffer is required. The following table shows the optimum ACK value versus your longest range to a particular client. Note that you cannot set an ACK value for each client so this is the maximum range for all of the clients.

  7. Max Link Distance ACK
    (in Meters) (in Feet) (in micro seconds)
    300 984 1
    600 1969 2
    900 2953 3
    1200 3937 4
    1500 4921 5
    1800 5906 6
    2100 6890 7
    2400 7874 8
    2700 8858 9
    3000 9843 10

  8. RTS and Fragmentation Threshold
    Optimum Setting: In general, you should not change the Fragmentation Threshold and Request-to-send (RTS) Threshold unless you are in an area with a lot of APs. Lowering the RTS Threshold (which is by default set to 2346, the maximum 802.11 frame size) causes your device (could be a station or an AP) to use Request-to-send/Clear-to-send (RTS/CTS) whenever it sends data. It actually is a protocol that clears the channel before data is sent. The RTS clears the area around the transmitter while the CTS clears the area around the receiver.

  9. How it works: Lowering your RTS Threshold will reduce collisions in an area with lots of Wi-Fi on the channel. In apartment complexes, hotels and offices you'll often find more than one AP occupying each channel, and in those cases, RTS/CTS usually helps WLAN performance by eliminating most collisions. RTS/CTS does add overhead to the channel because RTS and CTS frames don't contain data, but in a crowded area it usually helps, not hurts.

  10. Fragmentation is a little bit different from RTS/CTS in that the protocol overhead often causes it to harm the network. The idea with fragmentation is that smaller transmissions will result in better performance if there's lots of interference around. Best practice is to only lower your fragmentation threshold if there's significant interference in the area, and even then the results should be tested.

  11. DTIM and Beacon Interval
    Optimum Settings: If your WiFi clients support this feature, tweaking it can slightly improve the battery life on your WiFi devices. The default value for DTIM is 1. For best battery life on your WiFi devices, you may want to increase your DTIM Interval and Beacon Period a little bit to squeeze a little more battery life out of smaller devices. However, note that broadcast and multicast data get buffered on the AP between DTIM beacons. If your WiFi devices use time-sensitive applications that use a lot of broadcasts or multicasts (like VoIP for example), you should stick with the DTIM defaults.

  12. How it works: DTIM stands for Delivery Traffic Indication Message. Most modern (meaning post-802.11b) Wi-Fi devices come with this power saving features. To see if your WiFi device allows you to change the DTIM, check your client utility and the adapter's advanced properties (Properties > Configure > Advanced).

  13. APs have two config settings - Beacon Period and DTIM Interval - that will affect a station's battery life. The basic idea is that a higher DTIM Interval and/or Beacon Period will allow your stations to sleep longer. Stations have to wake up for every DTIM beacon, so the product of those two settings tells your station how many milliseconds it can sleep for (e.g., if DI=4 and BP = 100 your WiFi devices are allowed to sleep for up to 400 ms). For best results in areas wit poor receptions, set your Beacon Period to 50.