New router - printer not working
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Exactly! That was the point!No, those 3 channels are only completely isolated FROM EACH OTHER !!!
That's plain wrong! If you use channel 2 you will get so much noise from channels 1, 3 and 6! Pretty much all of them!OK, I'll give you a real-world example....
I can "see" 3 WAPs on ch1, and 3 on ch6 when upstairs in my house. The typical signal strength from the ch1 WAPs is -95dB, and -75dB from the ch6 WAPs. My WAP is producing -55dB at that same physical place. What channel am I going to set my WAP to?? I want the minimum signal overlap as possible (assume 7-11 is way more overcrowded with stronger WAPs so isn't viable...
Optimal throughput is actually achieved in this scenario by using ch2....using ch1 leads to infrequent, intermittent loss of authentication. 3,4,and 5 give increasing amounts of loss of authentication and signal attenuation as you get closer (and therefore more RF energy) to and overlapping with ch.6....
A few points that don't seem clear to you. I don't want to sound arrogant but I really don't see that you have understood them:
1) You are convinced that Channel 1 is 'barely' detectable as you only get -95dB. That's wrong. And that was part of the test by Cisco. What happens to all the devices (phones? Laptops?) that are connected to that WAP and are much closer to you than the access point itself? Those too transmit on Channel 1, and they are also part of the traffic
2) Whoever used channel 3 made an error. The only way of getting away of that channel is by using channel 8 (no overlap). That leaves you with only 2 channels usable (3 and 8): so now you have to fill in a space with WAP only using 2 channels instead of three.
3) What you are not getting is the fact that NOISE and WiFi transmissions are two separate things to WiFi devices. A device Y (WAP, laptop, phone, etc) listening/transmitting on channel 6 will use the bandwidth mentioned earlier. If another device Z on the same channel is already transmitting, device Y holds fire until the channel is clear. It's able to do that because he listens to the same channel. If device Z, on the other hand, was using channel 3 (for example), device Y WOULD NOT understand a thing about what that is, because it's basically missing part of the transmission and whatever it detects, it considers it as noise rather than WiFi communication. When there's noise (same happens with noise from microwave ovens for example), device Y transmits anyway, but this obviously leads to interference for both device Z and Y. Remember that if a WAP transmits on a channel, there's a bunch of devices all around it transmitting on the same channel.
In the scenario you presented earlier, the main issue is the device using channel 3. In that case you are still better off using the least congested channel among 1, 6 and 11.
If you use channel 2, you get NOISE from all devices using channels 1 (and that's not just the WAP), 3 and 6.
If you use channel 1, you only get noise from devices using channel 3. Devices already on channel 1 do not pose a noise-threat, as your device (WAP, laptop or else) are already using the whole spectrum of channel 1 and are therefore able to understand all communication taking place on that channel. That leads to coordination among all devices on that channel, something that cannot happen if parts of the WiFi transmission is missing due to a different channel width.
Any network engineer will tell you this. There is no reason of using channels other than 1, 6 and 11 in the 2.4Ghz band, unless you want to annoy people like me that always complain about people setting up WiFi in the wrong way and causing issues
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there's so much wrong in that last post......and certain parts also prove you can't either read and/or understand what's presented. If you read the cisco paper properly, they were all WAPs on a single network, which is obviously going to give different results to a multi-network environment....and no-one mentioned channel 3..........Gettin' There, Wherever There is......
I have a dodgy "i" key, so ignore spelling errors due to "i" issues, ...I blame Apple0 -
This is getting ridiculous now.
What difference does it make if you have 1 network or 50 networks? Do you know what a network is? What difference does it make if you have 4 access points and 1 network or 4 access points and 4 networks? If you are talking about LAN networks, do you know that we are talking about a different layer?If you read the cisco paper properly, they were all WAPs on a single network, which is obviously going to give different results to a multi-network environment....and no-one mentioned channel 3....
No one mentioned channel 3? In your example you said that you could see three access points on channels 1, 3 and 6. I think I am still able to read simple text?
Anyway, if you are still convinced that you are correct, happy days, I am not here to fight battles, if you are interested in the topic Google offers wonders.0 -
This is getting ridiculous now.
What difference does it make if you have 1 network or 50 networks? Do you know what a network is? What difference does it make if you have 4 access points and 1 network or 4 access points and 4 networks? If you are talking about LAN networks, do you know that we are talking about a different layer?
No one mentioned channel 3? In your example you said that you could see three access points on channels 1, 3 and 6. I think I am still able to read simple text?
Anyway, if you are still convinced that you are correct, happy days, I am not here to fight battles, if you are interested in the topic Google offers wonders.
I suggest you go and read it again... I said there are three operating on ch1, and three operating on ch.6.... really think you've misunderstood.... a lot..........Gettin' There, Wherever There is......
I have a dodgy "i" key, so ignore spelling errors due to "i" issues, ...I blame Apple0 -
You are correct, I missed a 'ch'. That doesn't change a thing of what I wrote earlier.I suggest you go and read it again... I said there are three operating on ch1, and three operating on ch.6
If you have three devices on ch1 and three on ch6, using ch2 will give you NOISE from all the devices on channels 1 and 6, plus you will disturb all communications happening on channels 1 and 6. And this is where people like me gets annoyed: you set up your WiFi system the best you can and then your neighbour decides not to stick to the rules.
If you use ch1 or ch6 you don't get ANY NOISE AT ALL and get MUCH BETTER performance.0 -
Nope, you should ALWAYS use channels 1, 6 and 11 as these are the only 3 channels in the 2.4Ghz band that DO NOT overlap with each other.
So wireless access point manufacturers are part of a great conspiracy in allowing users to use channels other than 1, 6 or 11...?
Maybe there should be a law passed to stop manufacturers from permitting settings that should NEVER be used...?
Or you might be wrong.0 -
You are correct, I missed a 'ch'. That doesn't change a thing of what I wrote earlier.
If you have three devices on ch1 and three on ch6, using ch2 will give you NOISE from all the devices on channels 1 and 6, plus you will disturb all communications happening on channels 1 and 6. And this is where people like me gets annoyed: you set up your WiFi system the best you can and then your neighbour decides not to stick to the rules.
If you use ch1 or ch6 you don't get ANY NOISE AT ALL and get MUCH BETTER performance.
So let's say you have three neighbours equally far apart. One is using wifi channel 1, the other channel 6, and the last channel 11.
Are you seriously saying that you'd get "MUCH BETTER" performance if you set up your own network on one of these congested channels?! That's ridiculous. You'd want your own network to overlap as little as possible with neighbouring networks.0 -
No, again you are missing the whole point of 'noise' and 'WiFi communication'.So let's say you have three neighbours equally far apart. One is using wifi channel 1, the other channel 6, and the last channel 11.
Are you seriously saying that you'd get "MUCH BETTER" performance if you set up your own network on one of these congested channels?! That's ridiculous. You'd want your own network to overlap as little as possible with neighbouring networks.
If you get a 100% overlap (i.e. using the same channel), you will get a much better performance than using adjacent channels (i.e. 6 and 7 opposed to 6 and 6).
This is because, as I already explained earlier, all devices on the channel are able to coordinate with each other. This can't happen if devices are in channels 6 and 7: they can still 'hear' each other, but they won't be able to understand if that's WiFi communication or just background interference as part of it is missing (due to the devices listening to different portions of the 2.4 band).
If you want to have a more technical explanation, this happens because of the so-called CSMA/CA Carrier-sense multiple access with collision avoidance (I admit I had to Google this because I always get the name wrong).
A device will only transmits when it senses that no other device is transmitting on that channel. And we are obviously talking about WiFi transmissions, not generic 'radio' transmissions on that channel (that can also originate from microwave ovens, DECT phones, etc.).
If CSMA doesn't detect any other WiFi communication, it will transmit full power regardless of noise (at this point, partially-lost WiFi transmission is considered as noise as not understood).
In other words, if you are on the same channel, you can coordinate with each other. If you are on adjacent channels, you will start screaming and talking over each other. The closer you are to another channel, the more interference you will have, the more lost packets you will see.
If you are on the same (overcrowded) channel (and can't be in any of the remaining, non-overlapping two), you will only transmit when the channel is clear, and you have much better chances for your packets to be delivered and understood.
This is another explanation on a paper found online:When two or more access points or wireless clients (stations) that are in range of one another, operate on the same channel, they form one collision domain. If any two devices in the same collision domain transmit at the same time, their radio signals will collide, resulting in corruption or frame loss. Thus, transmission time on the wireless resource is shared among all devices in the collision domain (using CSMA/CA to avoid collisions with any device within range that is on the same channel).
Sometimes, wireless networks that are in range of one another operate on different, but overlapping, channels. This, too, affects the throughput of the networks. In this scenario, traffic from the neighboring network may not be detected by CSMA/CA, but can still cause interference, leading to corruption or frame loss.
...or also:Co-channel congestion is preferable to adjacent channel congestion because of the way the wireless conversations are managed.
[...]To recap, an open channel will always be best when deploying your wireless network, but if you have to share a channel, that’s okay too. Adjacent channel congestion is the one you’ll want to avoid[...]0 -
Unfortunately, you're STILL using examples of multiple access points on one single network.... that does not apply to, for example, my laptop using my SSID on ch1, as that is not communicating with joe bloggs' other SSID on ch.1...........Gettin' There, Wherever There is......
I have a dodgy "i" key, so ignore spelling errors due to "i" issues, ...I blame Apple0 -
It doesn't matter. You are talking about a different OSI layer.Unfortunately, you're STILL using examples of multiple access points on one single network.... that does not apply to, for example, my laptop using my SSID on ch1, as that is not communicating with joe bloggs' other SSID on ch.1.....
Wireless access points, including radio waves, operate on OSI layer 1 and 2 (media/signal/etc).
Networks are layer 3 (as an engineer you should know that).
Anyway, that applies to ANY network (I don't know why you are concerned about networks, since as I said they are on a different layer).
When a wireless access point transmits/receives data, it doesn't care about networks.
If you have 5 access points in one room, you can arrange them as a single LAN network or as 5 separate networks, that doesn't change the way the WAP communicate and coordinate with one another.
Radio signal is radio signal. Network is network.
And this also applies to your laptop on ch1 and joe's SSID on ch1 as well. It's all Wireless communication. The respective WAP's radios will coordinate, transmit and receive regardless of which network they belong to (again, networking is on a different OSI layer, radio signal is not involved there).
Going back to the CSMA/CA, that operates on layer 2 (the data link). What you define 'network' comes after that (layer 3).0
This discussion has been closed.
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