Sometimes when you change
some wireless settings for tuning your links have so far that the link is not established or work is not stable anymore and you do not remember what settings you have in the beginning. In this case you can use the command reset-configuration in wireless menu - it will reset all wireless settings for specific wireless interface and you will be able to configure the interface from scratch. Note that running this command also disables the interface, so please be careful to not execute this command if you want to configure the remote router using a wireless link that you want to reset the configuration.
What resend wireless and where to check it?
Wireless retransmission is when the card sends the frame and you do not accept re-acknowledgment (ACK), you send the frame again until you regain recognition. resend wieless can increase latency and reduce throughput of wireless wireless link. To check whether a connection has been retransmission wireless wieless you need to compare two fields in the wireless registration table: hw-frames and frames. Hw-frame if the value is greater than the value of the frame then it means that the wireless link makes retransmissions. If the difference is not so big, it can be ignored, but if-hw frame count two, three or four times or even greater than the number of frames then you need to troubleshoot wireless connection.
Can I compare frames with hw-frames are also on the link Nstreme?
counting only frames that contain the actual data. In the case of Nstreme, only the ACK can be transmitted in one frame, if no other data to send. ACK frame will not be added to the number of frames, but they will appear in the hw-frame. If there is traffic in both directions with a maximum speed (for example, there will be no-ack frame only), then you can not compare the hw-frame to frame as in the case of ordinary wireless link.
What the TX power values can I use?
Tx-power default setting is the maximum power of tx-card that can be used and taken from eeprom card. If you want to use a larger power tx value, you can set it, but do so at your own risk, as it may damage your card at last! Normally, one should use this parameter only to reduce the tx-power.
In general tx power controlling properties should be left at its default setting. Changing the default settings can help with some cards in some situations, but without testing, the most common result is the degradation of range and throughput. Some problems that may occur are:
overheating of the power amplifier chip and the card that will lead to lower efficiency and more data errors;
overdriving the amplifier which will cause more data errors;
excessive use of power for this card and may overload the 3.3V power supply board that the card is located in the resulting voltage drop and reboot or excessive temperatures for the board.
What is the TX-power-mode is the best?
TX-power-mode wireless card tells the tx-power value should be used. By default this setting is enabled.
default means that the card will use the power values from eeprom card tx and will ignore what the settings specified by the user in the field of power tx.
card-rates means that for different data rate tx-power is calculated based on the cards transmit power algorithm from eeprom card and as the argument takes tx-power value is determined by the user.
all-rates-fixed means all that the card will use the tx power value
for all data values specified by the user in the field of power tx.
Note that it is not advisable to use the mode 'all-levels-fixed' as a card tx-power wireless data rates higher and lower by forcing to use the tx-power rates remain well for higher data speeds may cause similar problems as in the previous question about the tx-power setting. For most cases if you want to change the tx power settings are encouraged to use the tx-power-mode = card-level and it is recommended to reduce and not increase the tx-power.
What is the CCQ and how these values determined?
Client Connection Quality (CCQ) is a value in percent that shows how the effective bandwidth is used regarding the theoretically available bandwidth maximum. CCQ is the weighted average value of Tmin / Treal, which can be computed for each frame is sent, where Tmin is the time required to send a given frame at the highest level without retries and Treal is the time required to transmit frames in real life (taking into account account necessary retries it takes to send and transmit frame rate).
What hw-retries setting?
The number of times to send the frame retried without regard to any transmission failure. Decrease in failure rate data and the frame sent again. Three sequential failures on lowest level supported suspend transmission to the destination for a period of on-fail-retry-time. After that, the frame is sent again. frame is retransmitted until successful transmission, or until the client disconnected after disconnect-timeout. Frame can be discarded during this time when the frame-lifetime has been exceeded.
What is the disconnect-timeout setting?
This interval is measured from third sending failure on the lowest data rate. At this time 3 * (hw-retries + 1) transmit data frames on the lowest rate had failed. During the disconnect-timeout packet transmission will be attempted on-fail-retry-time. If no frame can be transmitted successfully during the disconnect-timeout, the connection is closed, and the event is recorded as "extensive data loss". successful frame transmission resets this timer.
What noise-immune adaptive-setting?
Adaptive Noise Immunity (ANI) adjust the parameters of the receiver dynamic range to minimize interference and noise effects on signal quality [1] setting is added to the wireless driver for Atheros AR5212 chipset and the newer cards
How to measure the signal strength of wireless devices, when the access-list or a linked-list is used?
reported signal levels exponentially weighted moving average with smoothing factor of 50%.
What method of error correction is supported in RouterOS wireless?
ARQ method is supported in the protocol nstreme. Regular 802.11 standard does not include ARQ - retrasmission corrupt frame is based on the recognition protocol. RouterOS supports forward error correction coding (convolutional coding) with coding rate: 1 / 2, 2 / 3, or 3 / 4.
Setup
Amplifier will increase the speed on my link?
It depends on the quality of your signal and noise. Remember that you can probably get a better link with low output power settings, and a good antenna. Amplifier increases the noise and will only cause problems with the link.
Amplifier got a boost on both the transmitted and received signals. Thus, in "silent", where you're alone or with very little "noise" or "competition", you might get very good results. On the other hand, in crowded areas, with lots of wireless activity, you will also increase the signal received from any other competitors or sources of noise, which can dramatically lower the overall quality of the link. Moreover, in taking account EIRP to see if your link remains within the bounds of the law.
You can also get a better signal on the "11b only" radio, which saw most of 802.11g as "noise", thus screening better signal can be used.
How to improve wireless link with the hw-retries?
You must understand that for 802.11 device is really there is limited information (or "feedback" from the environment) that the device can be used to tune their behavior:
signal strength, which can be used to determine the best level of sensitivity of the receiver knows to send. Sill is not reliable account that the sensitivity varies for different recipients (eg change from time to time), the condition of roads that are not symmetrical (and the device can only measure the received signal strength), etc.
by receiving / not receiving recognition for frames sent.
Taking into account that the use of signal strength is not reliable, 802.11 devices are basically left with only "feedback" to fine-tune the operation - success / failure of the transmission. When the transmission failed (ACK is not received in time), there is no way how the sender can find out why it fails - either because of noise, multipath, direct interference (and the weather that disrupted the actual data or ACK frame itself) - the frame just did not make and generally does not matter "why". What is important is the packet error rate.
Therefore RouterOS implements the algorithm to try to use the most efficient medium in any environment using only limited information, giving users the ability to control the workings of the algorithm and describe the algorithm. And there are only a few use guidelines, not a set of values you should use in certain situations.
In general - hw-retries a bigger, better "feedback" is the ability of the device will provide a frame at a certain level (for example if the frame rate to 54Mbps transmission failed 16 times, it said more than if it fails with 2 retries) and the better can find the optimum transmit level, at the expense of latency can be introduced in the network - as long as all retries fail, the other devices in these channels can not be sent. So the larger hw-retries can be recommended for backbone links PTP - which note that the link must always be active). Hw-retries minus one makes the choice more quickly adapt to the expense of some accuracy (under 2 will not make sense in most cases, it may be advisable to link PTMP, where it is normal for links can connect / disconnect and keep the latency under is essential.
on-fail-retry-time and disconnect disconnect-timeout controls how the hardware will try to consider the remote "connect". disconnect-timeout larger will make the device do not "disconnect" the other party, even if there is a lot of losses in transmission rates as small as possible. This again is most useful for "weak" link is known that they "should" be formed (eg backbone link). In a large PTMP network disconnect-timeout longer will increase the latency in the network over time as the AP will try to send data to several clients who had just turned off (AP will try to do is to disconnect-timeout overall).
frame-lifetime makes it possible to track how long the AP tries to use frames for transmission before considering that it's not worth giving it (for example, if the delivery fails frames on the lowest level, on-fail-retry-time timer is activated, if during the lifetime of this frame- end, a particular frame is dropped and the next transmission attempt will happen with the next frame. "Disabled frame-lifetime means that wireless will ensure order in the delivery of" all data "frame no matter how long it takes, or" will drop the connection if all else fails ). This makes it possible to optimize for various types of traffic such as for real-time traffic - if the primary use of voip wireless networks, for example, it could make sense to limit the frame-lifetime, because voip tolerate a small loss is better than high latency.
Is it possible to use a wireless repeater with only one radio interface?
This setup is possible by using WDS on the wireless interface that runs in ap-bridge mode.
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