rfconfig command (Radio interface configuration)

The command is used to configure a radio module.

Syntax:

rf interface parameters...

Interface rf5.0 parameters:

• "band   XXX" - bandwidth (MHz) - {double (40)|full (20)|half (10)|quarter (5)}
• "grid   B G" - frequency grid - <bw> freq1[-freq2[/step]],... | clear
• "freq   XXX" - central frequency (MHz)
• "bitr   XXX" - bitrate (Kbps)
• "txpwr XXX" - tx power (dBm)
• "sid    XXX" - system identifier - up to 8 hex digits
• "cap" - RF capabilities
• "dist   XXX" - distance in kilometers or auto
• "txrt   XXX" - max transmit retries [15]
• "txvrt  XXX" - max transmit retries in voice mode [5]
• "[-]burst" - burst mode
• "[-]shortgi" - short guard interval mode
• "noise  XXX" - Noise floor threshold, dB [20]
• "[-]pwrctl" - automatic TPC mode
• "[-]wocd"
• "[modulation OFDM | CCK]"
• "[chntime XXX]"
• "[statistics]"
• "[-]bcsid".

Sets parameters of a radio module specified by the if-name (name of the radio interface) parameter, or displays them if executed without any optional parameter. Optional parameters are as follows:

• "band XXX" - this option allows choosing the bandwidth for transmission (in MHz). Double means 40MHz, Full - 20MHz, half – 10MHz, quarter – 5MHz. Units in one PtP or PtMP connection must have the same bandwidth.

Example,

rf rf5.0 band half

• "grid B G" - this option allows creating a customized frequency grid within the license restrictions. The frequency grid for every band is formed in the form of a list of sub ranges with the defined frequency step (start frequency–end frequency/step), or a list of comma delimited standalone frequencies.

Syntax:

IFNAME grid BAND FREQUENCY_RANGE_LIST

Example,

rf rf5.0 grid 40 4920-5940/5
rf rf5.0 grid 20 5310-5390/10,5450,5500-5580/20
rf rf5.0 grid 10 5480, 5500, 5520, 5540, 5560, 5580

The resulting frequency grid can be viewed in the “rf cap” command output and is used every time the frequency is setup using the “auto” command (roaming, dfs etc).

To remove a frequency grid:

rf IFNAME grid BAND clear

That will restore the default frequency grid supplied in the unit’s license.

• "freq XXX" - central operating frequency (in MHz). Must be equal at the both sides of the link. The list of allowed frequencies can be obtained by executing "rf if-name cap" command.
• "bitr XXX" -  the bit transfer rate (in Kbit/s) of the radio link. Allowed values are:
  • For CKK mode: 11000, 5500, 2000, 1000 Kbit/s
  • For OFDM mode (standard models): 6000, 9000, 12000, 18000, 24000, 36000, 48000, 54000 Kbit/s.
  • For OFDM mode (Xm models):
    • 5 MHz: 3250, 6500, 9750, 13000, 19500, 26000, 29250, 32500 Kbit/s
    • 10 MHz: 6500, 13000, 19500, 26000, 39000, 52000, 58500, 65000 Kbit/s
    • 20 MHz: 13000, 26000, 39000, 52000, 78000, 104000, 117000, 130000 Kbit/s
    • 40 MHz: 30000, 60000, 90000, 120000, 180000, 240000, 270000, 300000 Kbit/s.

The maximum bitrate is limited by the specific model.

If the router is configured as a BS and autobitrate mode is turned on, this parameter will specify the maximum transmitting speed for the BS.

• "txpwr XXX" - sets the emitting power of the transmitter (in dBm). The acceptable transmit power values can vary depending on the type of the radio module installed. The acceptable transmit power values can be viewed using the "rf <if-name> capabilities" command.
• "sid XXX" - system identifier of the router, a hexadecimal number in the range of 1H to FFFFFFH. All routers that are supposed to see each other on the same radio link must have the same identifier.
• "cap" - displays the capabilities of the radio module including acceptable transmit the information on power levels, frequencies etc.
• "dist XXX" - this parameter is used as an alternative method of link range configuring in order to set the exact distance value between two devices (in kilometers). This parameter changes time values for some delays and time-outs thus making possible to work on longer distances with smooth adjustment.

There are several ways to manage this parameter:

• To set an exact value (in kilometers)
• Use automatic distance calculation (by default). In this case the unit will calculate and set the link distance automatically. In the configuration an automatically calculated value is displayed after the auto parameter: auto (XX).

Auto mode is recommended!

If the distance parameter is set to 0 radio module will use default settings.

• "txrt XXX" - this parameter sets the maximum number of repeat requests (transmit retries) to be done when sending unicast packets. 15 by default
• "txvrt XXX" - this parameter sets the maximum number of repeat requests for data packets (excluding voice packets) in voice mode. 5 by default. The maximum allowed value is 64. Voice mode is turned on automatically when VoIP traffic appears
• "burst" - enables the BURST protocol. “-burst” disables the BURST protocol support. Enabled by default.

The BURST protocol consists in grouping several short packets with the same destination address on a radio link into larger packets, thus cardinally decreasing the response time for applications generating streams of short packets. Burst enabling relates to a radio interface as a whole, and means only that you want to use this mode in this device; but the BURST protocol can only work for destinations where it is also enabled at the other end, and only if MINT protocol is used at both sides.

Burst enabling does not induce any changes in the work of other devices in the network. The BURST protocol reaches its maximal efficiency on high throughput point-to-point "backbone" links.

Some statistics about BURST protocol operation can be viewed by using the "muf stat" command.

• "shortgi" - enables the short guard interval mode. Using short guard interval allows the device to increase its throughput by reducing the time interval between symbols being transmitted. However, this may significantly increase the intersymbol interference and, thus, cause a higher errors rate.

To disable type “-shortgi”. Enabled by default.

• "noise XXX" - sets Noise Floor Threshold for radio interface. Measured in decibel. By default Noise Floor Threshold is 20 dB. Noise Floor Threshold is defined as a positive shift relative to the current level of noise which is measured by a device. The unit begins data transmission only when there are no signals in the air that have signal level higher than Noise Floor Threshold. See Noise Floor and Noise floor Threshold values with “rf IFNAME stat” command
• "pwrctl" - enables Automatic Transmit Power Control (ATPC) on the per-packet basis. When it is enabled (“rf rf5.0 txpwr <power> pwrctl”) the system automatically adjusts device’s output power to the optimal value that is necessary and sufficient to maintain the maximum productivity of the link in the given conditions. Transmit power adjustment is estimated for each sending packet. The upper bound of output power values that can be set by ATPC is limited by the power value specified in “txpwr” parameter.
• “-pwrctl” disables ATPC. Enabled by default.
• "wocd" - disables carrier sense on the radio interface when sending data packets. May only be used on a base station working in WMA (Wireless Marker Access) mode. Reduces the number of retransmitted packets, thus increasing effective throughput of a multipoint radio link. "-wocd" re-enables the standard mechanism of permanent carrier sense. Initial setting is "-wocd" (carrier sense enabled)
• "modulation" - sets the modulation technique for the radio. For 5-6GHz radios OFDM mode is always turned on. For 2.4GHz radios both cck and ofdm modes are available:
  • cck
  • ofdm
• "chntime" - Channel Burst Time. The time for the unit to occupy the radio channel. By default – 0 (dynamic, is not displayed in the configuration). Set in microseconds. Recommended value for PtP links – 5000 (20 MHz channel width)
• "statistics" - displays the radio module's statistics with 1 second update interval.

Below tables show "rfconfig stat" command output for 5GHz and 2.4GHz devices:

• "bcsid" -  enables SID broadcasting (in beacon service packets which are regularly sent by the radio module). This feature is a potential weak place in the security because it lets the device to reply to subscriber's cards requests having no SID value (ANY). Though MINT protocol exclude the possibility of unauthorized network connection, such device's behavior leads to its unstable work, failures and communication link delays
• “-bcsid” disables SID broadcasting. Disabled by default.

Examples,

rfconfig rf5.0 sid 1 bitr 130000 freq 2427 burst
rfconfig rf5.0 bitr 300000 freq 5280 sid 01020304 burst
rfconfig rf5.0 txpwr 18 pwrctl