KB:Access Point

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This is the knowledge base section for Compex Access Points

Getting Started

Is there any difference between the Station mode and the Station WDS mode?

Station mode translates all the packets that pass through device to its own MAC address, thus resulting in a lack of transparency. Unlike the Station mode, the Station WDS enables packet forwarding at layer 2 level; it is fully transparent at layer 2 level. Station WDS must also connect to Access Point configured to Access Point WDS(or RootAP) mode.

Refer Wikipedia-WDS for more details.

How is WiFi repeater bridge (WDS) been done in CompexWRT, either using wds peer mode in driver or using 4addr method?

CompexWRT is using 4addr method to implement WDS.

What are the Advantages of the Pyramidal Antennas inside your Indoor AP Series?

The indoor Access Point MMZ Series contain a Pyramidal smart antenna and the advantages are -High Isolation -Strong anti-jamming capability -Good Coverage

How to reset to factory default?

Hold down the reset button for 8 seconds, while the board is in stable operation (not starting up), then the PCB will reset to factory default.

Are there any requirements for setting the Pre-shared Key?

This option is available when WPA or WPA2, with PSK selected. The pre-shared key is an alpha-numeric password between 8 and 63 characters long.

Can Station WDS work with any AP in the market?

Station WDS can work with most of the AP in the market, eg. Microtik, Ubiquiti, TPlink, etc.

How does LED indicator tell signal strength of wireless.

The LED indicators are summarized in the following table.


LED Description
Power (green) The Power LED emits a steady light when electrical power (normally at 24 V) is supplied to the board.
LAN (green) The LAN/Diagnostic LED is lighted dimly when the LAN ports are not connected. The LAN LED blinks whenever packets are transferred through any of the LAN ports.
LED#1 (red) LED#1 indicates the received signal strength (low).
LED#2 (orange) LED#2 indicates the received signal strength (medium).
LED#3 (green) LED#3 indicates the received signal strength (high).
LED#4 (green) LED#4 indicates the received signal strength (very high).

Does Compex AP support WatchDog Timer, eg. reboot on kernel panic ?

Watchdog Timer is a Linux feature and can be found in the hardware. CompexWRT supports watchdog timer. It will reboot on kernel panic. There is a counter which ticks and device will reboot when it reaches a certain number.

Does CompexWRT support 802.11w and 802.11s?

IEEE 802.11s: Mesh Networking, Extended Service Set (ESS); IEEE 802.11w: Protected Management Frames; CompexWRT does support both 802.11w and 802.11s.

Does CompexWRT support 802.11r standard?

CompexWRT client mode doesn't support 802.11r standard.

Does CompexWRT support 3G/4G in compex AP?

There is no 3G/4G support in CompexWRT. As the kernel used in firmware is quite old, and does not support newer 3G/4G cards.

Do note that Compex firmware/SDK does not have 4G/LTE support protocol ready and customer will need to port this functionality themselves. Note: All 4G modules are compatible with WPJ531 board since we have the USB signal connected to the MiniPCIe slot.

Does CompexWRT support monitoring mode in compex AP?

The existing CompexWRT firmware does not support monitoring mode. This can be done if modify the driver. Please contact tech support for this special build requirement.

In view of CompexWRT software, what is the distance limitation can be set in 802.11N and 802.11AC protocol in Compex AP?

For example, using WLE600 11AC wireless module, its maximum distance is 24km in all 11n, 11a, and 11ac mode, for all 20/40/80MHz channel bandwidth. On the other hand, WLE200 11N wireless module, it can support maximum 48km in HT20, 24km in HT40 and 12km in HT80. Hence it is not possible to go further distance to 60km.

Technical Support

Where can I find the Latest Firmware for All Access Points?

You will have identify your board model via the label on the AP, you could find our downloads at www.compex.com.sg

When I select the 20/40MHz, why is the link unstable?

Selecting 20MHz represents the data transmitted at a bandwidth of 20MHz. 20/40 represents the data transmitted at either 20MHz or 40MHz. In a very noisy environment, it automatically falls back to 20MHz to be more resilient to the interference. In case that auto fall-back does not happen, manually changing the channel spectrum width to 20MHz will help reduce interference on the link and improve performance. Moreover, 40MHz bandwidth is non-standard for 802.11g mode operation except 802.11ac/n. If you experience any unstable performance, change Channel Spectrum Width to 20M.

How many clients can Compex AP support?

This is up to RAM and CPU usage rate. It need to have good bandwidth management in order to support numbers of clients. Besides, DHCP server of Class C Network able to serves for 256 clients in total. Network environment also take into account for the coverage. In general, Compex AP could support 30 clients without issue.

How to minimizing interference?

  • Advertising your SSID including backhaul links between sites, so that other users of the band can take steps to avoid interference and conflicts. This not only makes it easier for users to connect, but also provides other wireless users with all the information needed to minimise interference. This information can be acquired easily via any wireless device when completing a site survey providing information about the user, channels used, general location and the direction in which antennas may be pointed.
  • Using your equipment correctly. Eg. Use the most appropriate antenna; Prefer antenna gain, receive sensitivy and transmit power; Ensure good antenna alignment on directional antennas.

How many of antenna gain should be used on AP device to support long distance range, eg. 24km?

For long distance range of 24km, we recommend to use at least 25dB of antenna with AP device. 25dB antenna is the strongest antenna gain that we have in Compex. Note: In the past we had been tested 11ac radio at 10km only with using 19dB of antenna.

What is ACK Timeout?

ACK Timeout: Acknowledgement Timeout Windows. When a packet is sent out from one wireless station to the other, it will waits for an Acknowledgement frame from the remote station. The station will only wait for a certain amount of time, this time is called the ACK timeout. If the ACK is NOT received within that timeout period then the packet will be re-transmitted resulting in reduced throughput. If the ACK setting is too high then throughput will be lost due to waiting for the ACk Window to timeout on lost packets. If the ACK setting is too low then the ACK window will have expired and the returning packet will be dropped, greatly lowering throughput. By having the ability to adjust the ACK setting we can effectively optimize the throughput over long distance links. This is especially true for 802.11a and 802.11g networks. Setting the correct ACK timeout value need to consider 3 factors: distance, AP response time, and interference. The AC.TOP provides ACK adjustment capability in form of either distance or direct input. When you enter the distance parameter, the AP will automatically calculate the correct ACK timeout value, it should have a value of 0-255 sec.

The issue with ACK is mainly if you are set short. Whichever side is sending data will keep sending it, since it doesn't get the ACK response back to confirm/ACKnowledge the packet was received. If you look at it as timing (which it is) You have a time schedule of 0-255 (default 91) The device is expecting that ACK to come back within the time frame of 0-91. If it doesn't, resend the packet. So falling short on ACK setting makes an almost/ if not, unusable link. Go long, is better. But adds a slight delay, since the radio will wait longer for the ACK. In turn, will reduce bandwidth a bit. That's part of why most say add a bit to your mileage for the ACK setting. It allows some timing overhead so your link doesn't just crap out.

Edit/ Addition:

You can have the same ACK timing "issues" with an overloaded AP also.. If the AP is too busy it won't send the ACK fast enough to the client. Thus another packet retry/resend. It's another thing to watch out for, and can daisy chain itself to a totally messed up AP site.

Troubleshooting

Tips for Improving Home Wi-Fi Performance

  1. Upgrade and Add AP - Wi-Fi technology continually improves. Newer Wi-Fi gear typically runs faster, is more reliable and offers better compatibility with your home electronic gadgets. The alternative involves installing an additional device called a repeater.
  2. Move the AP to a Better Location - The netowork might crashes when a microwave oven or cordless phone is turned on. One easy way to address poor WiFi performance is to simply move the wireless AP to a better location. More details for best place.
  3. Change the Wi-Fi Channel Number - Interference on a channel can impact your Wi-Fi network's performance. Most wireless routers ship with the same default channel numbers and you may experience radio interference from a neighbor's router on the same channel. Changing the Wi-Fi channel is often the best way to fix this problem. More details for best 2.4GHz channels and more details for best 5GHz channels.
  4. Upgrade Ap firmware - Updating your firmware can provide performance improvements, security enhancements or better reliability. Look for firmware updates on Compex's website changelog
  5. Increase Signal Strength and Range of the AP - Sometimes the Wi-Fi signal will simply not be strong enough to maintain a good connection. The likelihood of this problem increases the further away from the router a client is and the more obstructions, such as brick walls, stand between the client and the router. One way to solve this problem is to upgrade the Wi-Fi antenna installed on the AP.

Where is the Best Place For Your Wireless AP?

  1. Don't settle prematurely on a location for the wireless AP. Experiment; try placing the device in several different promising locations. While trial-and-error may not be the most scientific way to find a good spot for your AP, it is often the only practical way to assure the best possible Wi-Fi performance.
  2. Strive to install the wireless AP in a central location. If you have only one wireless client, installing the base station near this client is best. For WLANs with multiple wireless clients, find a good compromise position. Clients too far away from the AP will obtain only 10% to 50% the network bandwidth of clients nearby to it. You may need to sacrifice the network performance of one client for the good of the others.
  3. Avoid physical obstructions whenever possible. Any barriers along the "line of sight" between client and base station will degrade a Wi-Fi radio signal. Plaster or brick walls tend to have the most negative impact, but really any obstruction including cabinets or furniture will weaken the signal to some degree. Obstruction tend to reside closer to floor level; therefore, some folks prefer to install their wireless AP on or near the ceiling.
  4. Avoiding reflective surfaces whenever possible. Some Wi-Fi signals literally bounce off of windows, mirrors, metal file cabinets and stainless steel countertops, lessening both network range and performance.
  5. Install the wireless AP at least 1m (3 feet) away from other home appliances that send wireless signals in the same frequency range. Such appliances include some microwave ovens, codrless telephones, and home automation equipment. Appliances that transmit in the 2.4GHz frequency range ar most likely to generate Wi-Fi interference.
  6. Likewise, install the router away from electrical equipment that also generates interference. Avoid electric fans, other motors, and fluorescent lighting.
  7. If the best location you find is only marginally acceptable, consider adjusting the AP's antennas to improve performance.

Which 2.4GHz Wi-Fi Channel is Best?

The three Wi-Fi channels 1,6,and 11 have no frequency overlap with each other. Use one of these three channels for best results.

Which 5GHz Wi-Fi Channel is Best?

Choices vary by country but in the US these non-overlapping 5GHz channels are most recommended: 36, 40, 44, 48, 149, 153, 157 and 161.

Note:Usable non-overlapping 5 GHz channels also exist in between 48 and 149, specifically - 52, 56, 60, 64, 100, 104, 108, 112, 116, 132, and 136. These channels fall into a specially regulated category where a Wi-Fi transmitter is required to detect whether other devices are already transmitting on the same channel and automatically changes its channel to avoid conflict. While this Dynamic Frequency Selection (DFS) feature avoids interference issues, many network administrators simply avoid using these channels altogether to minimize complications