Manual:Network/WiFi

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WiFi

Clicking on the Network ➤ Wifi tab would bring you to the Wireless Overview page. This page shows the radios present on the device. These may include the on-board radio and the miniPCI/miniPCIe radio card.

The wireless local area networks (WLANs) are displayed under each radio.

CpxWRT Network WiFi Overview.png

The Wireless Overview page showing two radios.

The two tabs are shown at the top, wifi0: Master “M8” and wifi1: Master “M7”. These correspond to the two radios shown below.

The buttons are explained as follows.

Spectrum: Shows the Channel Scan Report and allows you to run the Interference Analyzer.

Add: Allows you to add virtual access points (VAPs) to the radio. By default, there is only one VAP on the radio. Each VAP corresponds to one network.

Enable: Enables the radio.

Disable: Disables the radio.

Edit: Brings you to the configuration page of the network. Clicking this button is equivalent to clicking the corresponding tab above e.g. wifi1: Master “M7” for the radio with SSID given as “M7”.

Radio in AP Mode

When a radio is operating as an AP, the section for Associated Stations shows a list of stations connected to this device.

CpxWRT Network AP Mode.png

The MAC address, network name, received signal strength, noise power, transmit rate, receive rate, and transmission quality for each station are displayed.

Spectrum: Interference Analyzer

For a radio in AP mode, clicking the Spectrum button would bring up the Channel Scan Report.

CpxWRT Network Channel Scan.png

The button 'Radio 1 View' shows the number of neighbouring access points for each channel, the Min RSSI, Max RSSI, Noise Floor, and Channel Load.

Min RSSI: Shows the minimum received signal strength indicator due to the neighbouring access points.

Max RSSI: Shows the maximum received signal strength indicator due to the neighbouring access points.

Noise Floor: Shows the level of the noise on the channel.

Channel Load: Shows how much the channel is utilized. A lower channel load denotes a channel with less interference.

You can click 'Radio 1 Scan' to do the full channel scan again and get the latest results.

The buttons for Radio 2 would be shown if Radio 2 is enabled on the device.

Return: Brings you back to the Wireless Overview page.

Radio in Station Mode

A radio can operate as a Station. This can be set in the Interface Configuration ➤ General Setup ➤ Mode option, after clicking on the Edit button.

CpxWRT Network Station Mode.png

The following buttons are for a radio operating as a station.

Scan: Scans for available wireless networks. This button is available if the device is operating as a Station. You can then select the network to connect to.

Join Network: Associates this device with the selected wireless network.

List of AP will be generated upon clicking on Scan button.

Scan 1 2 3.png

You may check the box Enable Scan List to choose which channel to be scanned.

Enable scan list 1.png

For example, The radio can scan channel 1 only when you check channel 1. All AP which is channel 1 would be listed.

Scan1.png

Device Configuration

The Device Configuration section consists of the section tabs for General Setup and Advanced Settings.

General Setup

Status: Shows a summary of the wireless network.

CpxWRT Network Device Configuration.png

Enable: Enables the wireless network.

Disable: Disables the wireless network.

Country Code: Selects the country. Each country has its own transmit power and frequency regulations. To ensure regulatory compliance, you must select the country where the device is operating in. The transmit power levels for each channel are tuned accordingly.

Wireless Profile: Chooses the wireless standard used. 802.11a and 802.11g are older standards while 802.11n is a newer standard that offers higher data rates. The choice of 802.11g+n is a combination of 802.11g and 802.11n, and operates in the 2.4 GHz frequency band. The choice of 802.11a+n is a combination of 802.11a and 802.11n, and operates in the 5 GHz frequency band. The 802.11ac is the latest standard that offers even higher data rates (up to 1300 Mbps) and it also operates in the 5 GHz frequency band.

Channel Spectrum Width: Selects whether 20 MHz or 20/40 MHz bands are used. A 40 MHz band has twice the throughput of a 20 MHz band. A smaller bandwidth may allow more devices to be connected. The 20/40 MHz option allows both 20 and 40 MHz bands to be used. When the 802.11ac wireless standard is used, the 20/40/80 MHz band can be selected. An 80 MHz band can carry twice the amount of data of a 40 MHz band.

Channel: Chooses the frequency channel. The default setting of Auto is may be used. For an AP, it would select the channel with the least interference from other APs. For a station, it would automatically select the same channel as its AP. The frequency channel may also be manually selected. An AP and its station must have the same channel in order to communicate.

Wiki ACS and Scan List 126.png

Background ACS scan: Automatic channel selection (ACS) is the feature whereby if the AP is not currently associated with a client, periodically, the AP will scan the channels and switch from a noisy channel to the least noisy channel. AP automatically scans and switches to the best channel after a period of time, the default being 60 seconds. Precondition: Dynamic Channel Selection (DCS) has to be enabled first - see below. When a client is connected to the AP, it will not scan. This is to prevent disconnect of the link.

Background ACS scan interval: AP scans for better channel every X seconds, X ranging from 60s to 86400s. The default is 60 seconds.

Obey Regulatory Power: Obeys the power regulations specified by each country. This would satisfy the legally permitted maximum for the equivalent isotropically radiated power (EIRP) limits of the selected country, based on the specified Antenna Gain (dBi). The result is that the maximum transmit power may be less than the capability of the radio. Once activated, a refresh of the webpage may be needed to show the settings correctly. If “No Country” is selected, this is not in use.

Antenna Gain (dBi): Represents the gain relative to an isotropic antenna. An antenna with a higher antenna gain focuses the transmit power more towards a certain direction, with less going to other directions. When Obey Regulatory Power is checked, the value of the antenna gain would be taken into account to limit the selectable transmit power, such that the EIRP limits of the country are satisfied.

Transmit Power (dBm): Limits the maximum transmit power of the card at that particular frequency, e.g. 4 dBm, 5 dBm, …, 22 dBm or “Max”. This is the power supplied to the antennas of the radio. The minimum transmit power values for the radios are:

  • For 1-Chain: 1 dBm
  • For 2-Chain: 4 dBm
  • For 3-Chain: 6 dBm

The “Max” power depends on both the country and the frequency channel used.

Outdoor Channels: Limits the available channel frequency selections to 5500-5700 MHz if the country is in the European Union (EU). Based on the EU-Rule 2005/513/EC regulation, only this frequency band is allowed for outdoor use.

For non-EU countries, Outdoor Channels options is not applicable.

Understanding the Maximum Transmit Power Calculation

The maximum transmit power calculation is illustrated with the following examples.

Example 1

  • Country Code: US, Channel = 36
  • Obey Regulatory Power is enabled
  • Antenna Gain is 5dBi
  • Transmit Power is 15dBm
  • Outdoor Channels is disabled

In the US, Channel = 36 would mean the maximum power is 17dBm for EIRP. Transmit Power is 15dBm, so when adding Antenna Gain of 5dBi, it would be 20dBi, which would EXCEED the EIRP. Thus the “Max” transmit power of the card has to be 12dBm, so that when added with 5dBi, it would be 17dBm.

Example 2

  • Country Code: US, Channel = 149
  • Obey Regulatory Power is enabled
  • Antenna Gain is 5dBi
  • Transmit Power is 15dBm
  • Outdoor Channels is disabled

In the US, Channel = 149 would mean the maximum power is 30dBm for EIRP. Transmit Power is 15dBm, so when adding Antenna Gain of 5dBi, it would be 20dBm, which would NOT EXCEED the EIRP. Thus the “Max” transmit power of the card is 15dBm, as Antenna Gain has no effect.

Example 3

  • Country Code: CZ, Channel = 100
  • Obey Regulatory Power is enabled
  • Antenna Gain is 5dBi
  • Transmit Power is 15dBm
  • Outdoor Channels is enabled

In the Czech Republic, Channel = 100 would mean the maximum power is 30dBm for EIRP. Transmit Power is 15dBm, when adding Antenna Gain of 5dBi, it would be 20dBi, which would NOT EXCEED the EIRP. Thus the “Max” transmit power of the card is 15dBm, as Antenna Gain has no effect.

5MHz and 10MHz Channel Spectrum Width

This feature is only available in v1.87 or upwards firmware currently.

From dropdown list of Country Code, choose Half/Quarter Channel. Click Save & Apply to save the configuration.

Wiki 5 10 MHz Picture1.png

Refresh the page and then you will see 5MHz and 10MHz in Channel Spectrum Width.

Wiki 5 10 MHz Picture2.png

Choose 5 MHz or 10 MHz. Bitrate will change to 32.5 Mbit/s and 65 Mbit/s for 5 MHz and 10 MHz respectively.

Wiki 5 10 MHz Picture3.png

Wiki 5 10 MHz Picture4.png

Advanced Settings

CpxWRT Network WiFi Advance Settings.png

Distance Optimization (Auto-ACK Timeout): Determines the distance of the connected station from the AP and automatically adjusts the ACK timeout. This is disabled by default. If the stations are positioned over a wide area at different distances from the AP, it is recommended to disable this option to prevent the ACK timeout from fluctuating widely.

Distance (meters): Specifies the distance between the AP and the station, if the previous option is unchecked. Min: 300, Max: 12000 (80MHz), 24000 (40MHz), 48000 (20MHz). This value should be set to slightly more than the physical distance between the AP and the farthest station.

For example, a customer had an AP on top of a building. They had multiple stations on top of nearby buildings, at various distances. The APs were involved in video transmission. They experienced unstable network performance with Auto-ACK enabled. This is because when a station nearby is communicating, the ACK timeout reduces. When a station farther away is communicating, there will be retransmissions, before the ACK timeout is lengthened again. When they fixed the Distance for the ACK timeout, this problem is resolved.

Chainmask Selection: Sets the antenna port selection on the radio. For example, 2x2 means that 2 antennas are being used.

Note: The following options are for the device operating as an access point (AP).

Beacon Interval: Specifies the interval between beacon transmissions by the AP, in ms. A beacon is a frame broadcast by the AP to synchronize the wireless network. For the multiple VAP case, the beacons are transmitted evenly within this interval.

For example, if four VAPs are created and the beacon interval is 200 ms, a beacon will be transmitted from the radio portion every 50 ms, from each VAP in a round-robin fashion. The default value of the interval is 100 ms.

Adaptive noise immunity: Controls radio sensitivity in the face of noise sources. Adaptive noise immunity allows the AP to reject spurs and non-WLAN noise. An advantage is that the AP would have to spend less time decoding the signal, resulting in lower packet loss rate.

Dynamic channel selection: Automatically switches channel to avoid interference. Dynamic channel selection (DCS) is feature to detect and avoid continuous wave (CW) interference. CW interference or spurs cause the noise floor to be high. This stops transmissions as well as causes receives to fail frequently.

The noise floor is monitored by the calibration logic. When the noise floor is above a threshold, the AP is performs an automatic channel selection. It would disconnect from the stations (it would already have due to the interference) and move to a new channel. The stations are expected to re-associate with the AP on their own.

Interface Configuration

The Interface Configuration section contains the section tabs for General Setup, Wireless Security, MAC-Filter, and Advanced Settings.

General Setup

CpxWRT Network WiFi Interface Configuration.png

Mode: Selects whether the device is operating as an Access Point (AP) or a Station. Other options are Access Point WDS and Station WDS.

Note: Setting more than 1 station on a board is not supported because there can only be one default gateway. This is true even if a board has both an onboard radio and a card radio. Both radios cannot be in Station mode at the same time.

ESSID: Specifies the name or extended service set identifier (ESSID) of the wireless network as it is provided in the beacon message. The network name can be up to 32 characters in length and can contain spaces. When running in AP mode, it is the name of the network as advertised in the beacon message. In Station mode, it is the network name that the station associates with.

BSSID: Sets the MAC address of the AP. This option is available for a device operating as a station. This is useful because there can be multiple APs with the same ESSID. Setting the MAC address would prevent the station from roaming to other APs. Guard Interval: Chooses between Short and Long guard intervals. Guard intervals are used to ensure that distinct transmissions do not interfere with one another. Data rate is improved in downlink and uplink if both AP and station use the Short Guard Interval.

Data Rate (Mbps): Selects the data rate or the modulation and coding scheme (MCS). The default setting of Auto is recommended. The MCS and data rates are adjusted automatically depending on the wireless channel conditions.

Note: To simplify chainmask setting process, data rate had been simplified to MCS index from 0 to 7. The MCS index remains the same from index 0 to index 7 even though chainmask setting is changed to different level, which is 1x1, 2x2 or 3x3. However, a same MCS index actually carry different values for each level of chainmask setting. E.g. MCS 3 has different values (3, 11, and 19) for different levels of chainmasks, but they all use the same modulation type and coding rate.

Hide ESSID: Hides the network name (ESSID) from being broadcast publicly. (This option is for a device operating as an AP.)

Note: If the goal is securing your network, use WPA or preferably WPA2 encryption. Hiding the ESSID does not provide complete security.

WDS

A Wireless Distribution System (WDS) is a system enabling the wireless interconnection of access points in an IEEE 802.11 network. It allows a wireless network to be expanded using multiple access points without the traditional requirement for a wired backbone to link them. The notable advantage of WDS over other solutions is it preserves the MAC addresses of client frames across links between access points.

WDS may also be considered a repeater mode because it appears to bridge and accept wireless clients at the same time (unlike traditional bridging). However, with this method, throughput is halved for all clients connected wirelessly.

Setup for the WDS Modes

The wireless distribution system (WDS) allows the Station WDS to bridge wireless traffic transparently, providing the functionality of a repeater. The Station WDS is a transparent client and would need to associate with an AP WDS. The WDS protocol is not defined as a standard so there may be compatibility issues between devices from different vendors. The following figures show an example of a setup.

CpxWRT Network AP WDS mode.png

The first router is set to the AP WDS mode.

CpxWRT Network Station WDS mode.png

The second router is set to the Station WDS mode.

Multiple stations or Stations WDS can connect to an AP WDS. In the previous figure, the Add button creates a virtual access point (VAP) on the second router. You should choose AP WDS mode for the VAP's wireless network e.g. “M8” so that devices in Station WDS mode can connect to this network.

The pair of Station WDS and AP WDS on the same board extends the wireless coverage. If the board has two radios, one onboard and one card radio, one radio can be the Station WDS and the other radio can be the AP WDS. Therefore the Station WDS with AP WDS on the same board functions as a repeater.

In the non-WDS mode, the Station translates all the packets that pass through it to its own MAC address, thus resulting in a lack of transparency. A consequence is that the ARP table of the access point would show the MAC address of the Station assigned to IP addresses of both the Station and the computer connected to it.

Mesh

Mesh Configuration