[SOLVED] Set up 2 routers for better coverage

hw_user

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I am using 2 routers for WIFI coverage. The first router (RT1) is connected to the ISP modem and provides DHCP. The second router (RT2) is ethernet connected to the first router and has DHCP disabled. These routers are both dual band (2.4G, 5G) and have channel set up as 'auto'. The first router has SSID "RT1_24G , RT1_5G" and the second router has SSID "RT2_24G, RT2_5G". The setup is working fine.
When I search internet, I found people talking about these 2 routers should be on different channels. Can some some one help me to understand the reason behind it ? Is there any difference between using the same SSID and using 2 different SSID on the 2 routers.
 
Solution
The solution you are using is actually the best option. You the human know much better than any of the equipment what is the best signal. It all depends on how much it actually bothers you.

The other option is to use the same SSID and just stop and start the wifi in the device. That tends to be a bit faster but the end device still can pick the wrong connection.

Your problem is you actually have too much signal. If your router has the option try to reduce the signal power. The method end devices use to decide to switch is based on the power level. When it drops below some point it will search for another. This point is what the roaming aggressiveness option affects. This takes a lot of playing around to get the...

OrlyP

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SSID and Channels are two, unrelated parameters.

SSID
In a nutshell, the SSID you assign to an access point's radio (either or both 2.4/5GHz) is the identifier that it will broadcast (by default) to which mobile devices can connect to. Ideally, if you only have one network at home (ie. one subnet), it's best to keep the SSIDs and its pre-shared kays exactly the same on all your APs so roaming between them is seamless and doesn't require your mobile device to switch SSIDs. This also offers the added benefit of not having to setup multiple SSIDs for each of your devices.

WiFi Channels
Here's the skinny on WiFi channels.... you can't have two or more APs that close to each other use the same or adjacent overlapping channel. Otherwise, they will cause interference and lower your overall WiFi range and throughput. In other words, you'd want your APs configured to use non-overlapping channels.

The diagram below lays down the available channels on both 5 and 2.4GHz. So, for example, if you use 80MHz bandwidth on 5GHz, you can assign up to 6 APs with non-overlapping channels (42, 58, 106, 122, 138, and 155), assuming your APs can use those channels. However, if you're already using channel 42, for example, you can no longer use channels 36, 38, 40, 44, 46, 48, and 50 on your 2nd AP if it's within "earshot" of the first AP, as these channels will overlap and cause interference with channel 42.

For 2.4GHz, best practice is to use the non-overlapping channels 1, 6, and 11, for the same reason as explained above.

DUced8oXkAAkO0O.jpg
 
In general any information about non overlapping channels is outdated.

Since routers on the 2.4g use 40mhz and there is only 60mhz total you can't fit 2 signals.

On the 5g band it uses 80mhz channels. There are only 2 block you are allowed to use. The 2 green ones in the chart posted above. All the ones in DFS you are not allowed to set manually. Many routers and end devices do not support the DFS channels because of all the rules.

So you could set one router to 42 and the other to 155. You could also leave them on auto and see if they do it themselves. The risk is they assign a DFS band and your end devices do not work on those frequencies.

If your main router signal is strong enough to interfere with the remote router then you kinda don't need the remote router in the first place.

Of course the biggest issue with any of this assumes that you live in some magic building where you have no neighbors attempting to use wifi. Almost all the current wifi issues is that everyone is attempting to use up all the radio channels. They are putting in all these fancy tri-band routers and mesh systems that are just stomping on each other. The only hope is the new wifi6e starting to get to market. The 6g radio band has massive amounts of bandwidth.....but I am sure the router guys are trying to figure out how to use all of it on 1 device.
 

OrlyP

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AFAIK, it's not illegal to use DFS channels. The FCC has opened up these channels for WiFi use for as long as your APs has that DFS mechanism.

Dynamic frequency selection (DFS) is a mechanism that dynamically detects signals from other systems and avoids co-channel operation with these systems, notably radar systems.

If your AP supports these channels, they are likely to have DFS capability. Otherwise, they won't be sold in the US or those channels will be hidden.

I have had no issues using the DFS channels. I can see my client devices happily connect to them (ch. 58 and 106) as much as on the non-DFS channels 42 and 155. Though, I had to be a strategic in AP channel assignments. I have four APs; 2 on the ground floor and another pair on the 2nd floor. I found out that if I assigned DFS channels to the 2nd floor APs, I get a "Radar detected" notification several times a week. But if i assign them on the ground floor APs, no more such notifications.

Obviously, the upper floor has the disadvantage of receiving more stray RF and are more likely to receive radar signals.

Granted, YMMV. Success using the DFS channels depends on your proximity to a nearby C band radar installation.
 
Most equipment you can not manually set them. Even if you do all it means is you "enable" the router to use them you can not force it to use them because the router will over ride you. So I guess it is more of a definition thing. If you are forcing it to use them then it is not running DFS detection. It is actually "illegal" to use the radio channels without radar avoidance.

Many end devices do not want to deal with this mess. Mostly this is because things like cell phone radios are designed to run in many different countries and it is just simpler to not support it rather than prove they meet all the legal standards for any country they are going to sell it in.

The other big problem is that many of the DFS channels do not allow full power usage so they tend to work much worse.

In the end it all doesn't matter the wifi performanace is horrible when you live in area with lots of other people. Use to be nobody even thought use a second router now everyone is cramming wifi radios in every room of their house. Without interference a fairly weak radio signal work very well. The biggest issue we have is way too much radio power around. This is like trying to fix the problem of your neighbors tv on too loud by turning yours up even louder.
 

OrlyP

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Most equipment you can not manually set them. Even if you do all it means is you "enable" the router to use them you can not force it to use them because the router will over ride you. So I guess it is more of a definition thing. If you are forcing it to use them then it is not running DFS detection. It is actually "illegal" to use the radio channels without radar avoidance.

True. I made that clear as well... If your AP legitimately supports those channels, they are likely to be DFS-capable and should exhibit this fact in its manual or datasheet.

Many end devices do not want to deal with this mess. Mostly this is because things like cell phone radios are designed to run in many different countries and it is just simpler to not support it rather than prove they meet all the legal standards for any country they are going to sell it in.

I ask this with curiosity. Is this a matter of fact or is it just an assumption? I see many WiFi SoCs on most modern WiFi-capable devices that supports DFS... at least based on their datasheets. And even if they don't, technically, they'll follow whatever channel the AP is at anyway. So, IMHO, it's more important for the AP to have DFS than the other way around.

This is a screenshot of my APs... the boxes in yellow shows that these APs are on the DFS channels and in fact, there are about equal number of clients connecting to DFS and non-DFS channels.

jKY58Js.png


The other big problem is that many of the DFS channels do not allow full power usage so they tend to work much worse.

I can't find any information about that. I know that your transmit power is limited to what the FCC allows on WiFi in general but it is not based on whether it's DFS or not.

If you look at the screencap above, the DFS channels are practically maxed out to the FCC limit for WiFi at these frequencies.

In the end it all doesn't matter the wifi performanace is horrible when you live in area with lots of other people. Use to be nobody even thought use a second router now everyone is cramming wifi radios in every room of their house. Without interference a fairly weak radio signal work very well. The biggest issue we have is way too much radio power around. This is like trying to fix the problem of your neighbors tv on too loud by turning yours up even louder.

That's why RF site-surveys and observing best practices with non-overlapping channels, power settings, and proper AP placements are still a thing... well at least in the commercial/enterprise sector. But these techniques are equally helpful in residential environments, if not more applicable.

TL;DR: At best, the DFS channels will be less crowded, owing to the fact that not all APs supports it. However, you are free to use the DFS channels if your AP supports it. But if you run into issues like if the APs are generating notifications that it's detecting radar, that's the only time to change it to a non-DFS (presumably more crowded) channel.
 
Your chart shows the power is 1/4 the other 2 bands even though I thought the limit was 500mw. The allowed power is very different from country to country which is why many routers just do not want to deal with this.

I forget which exact wifi chipset do not support it. You see people from time to time complaining that their phone can not see the 5g band on this forum. When they change the router channel it works

This may change as the chipset get more mature. If you look at the nwe wifi6 chipset for phones almost none support the 160mhz channels. This again is related to the DFS issue. Many routers also only run 80mhz on wifi6 and a lot of those do not support the DFS radio bands either. This is one of the huge reasons wifi6 does not perform a lot better than 802.11ac using 80mhz channels.

I am just waiting for wifi6e and we can forget about all these strange limitations since there are at least 9 160mhz blocks in the new 6g range.
 

OrlyP

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Well don’t hold your breath. Full adoption to WiFi 6 is still years ahead. You will always have stragglers on WiFi 5 or lower that will likely remain for at least several years. That said, even the WiFi 6 AP will still have to operate at WiFi 5 or lower to some degree to be downward compatible. There’s always incentive to optimize what you currently have.
 

hw_user

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My RT1 is for the main floor and RT2 is for second floor. Please correct me if I am wrong. I used the same SSID for both router before. But the device seems to be sticking to the first connected Router and does not switch as I go from main level to second floor. Performance was poor until I noticed something is not right. I had to disconnect and reconnect the device to cause it to connect to the second floor router (RT2). Still I wasn't sure if the switch has happened or not because the SSIDs are the same. That why I changed to use different SSIDs. When I move between floors, I will manually disconnect and reconnect to the correct router. I can leave it alone if I am not on something that needs the performance. I used a WIFI analyzer App. The couple of times I check the 2.4G of both routers are using CH 11. I will try to specify different channels for the two routers to see if there is any difference. With all my neighbors working from home, the 2.4G channels are all crowded. I am not sure if I can get any improvement. For 5G, my two routers are on different channels.
 

OrlyP

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My RT1 is for the main floor and RT2 is for second floor. Please correct me if I am wrong. I used the same SSID for both router before. But the device seems to be sticking to the first connected Router and does not switch as I go from main level to second floor. Performance was poor until I noticed something is not right. I had to disconnect and reconnect the device to cause it to connect to the second floor router (RT2). Still I wasn't sure if the switch has happened or not because the SSIDs are the same. That why I changed to use different SSIDs. When I move between floors, I will manually disconnect and reconnect to the correct router. I can leave it alone if I am not on something that needs the performance. I used a WIFI analyzer App. The couple of times I check the 2.4G of both routers are using CH 11. I will try to specify different channels for the two routers to see if there is any difference. With all my neighbors working from home, the 2.4G channels are all crowded. I am not sure if I can get any improvement. For 5G, my two routers are on different channels.
Ok, first thing.... change one of the router's channel to ch. 1 or 6, whichever is relatively less crowded. The WiFi Analyzer app should give you that indication. 2nd, play around with your routers' transmit power. Setting it to the highest setting isn't always ideal and would often contribute to the "stickiness" you're running into. What you want is for it to have just enough transmit power to work on the floor it's servicing. Once you go up/down another floor, the signal should be weak enough for the other router to take over.

On many Windows devices, you can play around with two parameters, if they're available:
  1. Preferred Band - Set this to "Prefer 5GHz" so it will prioritize connecting to 5GHz. If it fails, it will fallback to 2.4GHz
  2. Roaming Aggressiveness - Set this to Medium-high or High. The more aggressive, the more readily it will disassociate itself from a weaker AP . This can also help with the "stickiness"
 
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microtank

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Hell.. if your 2nd router is right next to other one that’s kinda pointless... cause I’d say screw it set up wds/access point mode in the ideal location. The only thing the 2nd wireless router would need is electricity and the gateway IP. I’m using 4 wireless routers on purpose and I’ve seen no issues on the bottom floor where I’m running tests for gaming. So... figure that one out
 
The solution you are using is actually the best option. You the human know much better than any of the equipment what is the best signal. It all depends on how much it actually bothers you.

The other option is to use the same SSID and just stop and start the wifi in the device. That tends to be a bit faster but the end device still can pick the wrong connection.

Your problem is you actually have too much signal. If your router has the option try to reduce the signal power. The method end devices use to decide to switch is based on the power level. When it drops below some point it will search for another. This point is what the roaming aggressiveness option affects. This takes a lot of playing around to get the settings correct.

I tend to use your first method since I tend to be in one place. This is one of those things that makes me laugh. Tplink shows a idiot watching his phone as he goes up the stairs and talks about their mesh system roaming. I wonder how that made it past the lawyers when you consider people walk in front of cars looking at their phone. Some people just can't be disconnected for even 1 second.
 
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hw_user

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The solution you are using is actually the best option. You the human know much better than any of the equipment what is the best signal. It all depends on how much it actually bothers you.

The other option is to use the same SSID and just stop and start the wifi in the device. That tends to be a bit faster but the end device still can pick the wrong connection.

Your problem is you actually have too much signal. If your router has the option try to reduce the signal power. The method end devices use to decide to switch is based on the power level. When it drops below some point it will search for another. This point is what the roaming aggressiveness option affects. This takes a lot of playing around to get the settings correct.

I tend to use your first method since I tend to be in one place. This is one of those things that makes me laugh. Tplink shows a idiot watching his phone as he goes up the stairs and talks about their mesh system roaming. I wonder how that made it past the lawyers when you consider people walk in front of cars looking at their phone. Some people just can't be disconnected for even 1 second.
It is very difficult to play with the signal strength. My situation is I have to place the router on the main floor closer to the back of the house in order to have WIFI access in the backyard. This makes weak signal spot close to the front of the house especially on the second floor. That's the reason I need the second router on the second floor near the front. The problem is in the area right above the first router. Enough signal is transmitted through the floor which makes the device confused about which one it should connect to. That's the main reason why I changed to use two different SSIDs.
For my education purpose, some one suggested me to spend the money to get a mesh WIFI system. Does it really make a different ? I know that the mesh system has the main module and satellite modules. (kind of like the router and APs). Does the device still has to connect and disconnect between the main module and the satellite modules as you move around different area covered by the mesh network ? Is there enough advantages over my current set up to justify the extra money ?
 

microtank

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It is very difficult to play with the signal strength. My situation is I have to place the router on the main floor closer to the back of the house in order to have WIFI access in the backyard. This makes weak signal spot close to the front of the house especially on the second floor. That's the reason I need the second router on the second floor near the front. The problem is in the area right above the first router. Enough signal is transmitted through the floor which makes the device confused about which one it should connect to. That's the main reason why I changed to use two different SSIDs.
For my education purpose, some one suggested me to spend the money to get a mesh WIFI system. Does it really make a different ? I know that the mesh system has the main module and satellite modules. (kind of like the router and APs). Does the device still has to connect and disconnect between the main module and the satellite modules as you move around different area covered by the mesh network ? Is there enough advantages over my current set up to justify the extra money ?
Are the 2 routers on the same floor next to each other or not? Cause WDS is basically mesh. If the mesh network needs 5 ghz to connect... you need multiple... like to get the best performance the devices need to “physically” see each other for the best signal. These wireless device are going to point A straight to point B. WDS nodes and Mesh nodes... whatever your priorities are... I mean the mbps plan is by far the most important thing to give an idea what can bring going on, then the set up and what devices are mandatory and what ones are not. Getting max bandwidth on one device... it’s only important for testing and mandatory downloads and uploads...

like.. buying more stuff isn’t going to fix anything. Especially when you already have 2 wireless routers.. what’s the mbps plan?
 
Mesh is mostly marketing to get people to buy new stuff. They figured people would not be tricked by putting "new and improved" so they put "MESH" on the box. It is your standard thing people think if it is something they don't understand then they must need it.

It purely is a better form of wifi repeater. It is used by people that do not have the option like your do to have the second router connected via ethernet. It must get a signal from the main router that is strong enough and still be able to transmit it to the remote location that has poor signal.

Now they pretend that you can get so called seamless roaming but that is not really true. The end device is in full control of what it connects to...unlike say a cell phone where the towers are in control. So the best a mesh system could do is try to force a device off the network and hope it connects better. The problem is the mesh network does not actually know the signal level the device is receiving it is basing its forcing based on the signal levels it receives which many times is very different.

It really doesn't matter what system you use proper wifi signal design is key to a good function system. This is what is called a site survey and the design of the location and power output of your wifi routers is key to good performance. Every house is different so every install is custom. There is no magic you have to do the work and figure out what is best for your house. Maybe a central located router and a outdoor AP would be better....all depends on where you have ethernet jacks.

This is actually a very complex problem people make their whole career wifi design and installation in business.
 
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hw_user

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Mesh is mostly marketing to get people to buy new stuff. They figured people would not be tricked by putting "new and improved" so they put "MESH" on the box. It is your standard thing people think if it is something they don't understand then they must need it.

It purely is a better form of wifi repeater. It is used by people that do not have the option like your do to have the second router connected via ethernet. It must get a signal from the main router that is strong enough and still be able to transmit it to the remote location that has poor signal.

Now they pretend that you can get so called seamless roaming but that is not really true. The end device is in full control of what it connects to...unlike say a cell phone where the towers are in control. So the best a mesh system could do is try to force a device off the network and hope it connects better. The problem is the mesh network does not actually know the signal level the device is receiving it is basing its forcing based on the signal levels it receives which many times is very different.

It really doesn't matter what system you use proper wifi signal design is key to a good function system. This is what is called a site survey and the design of the location and power output of your wifi routers is key to good performance. Every house is different so every install is custom. There is no magic you have to do the work and figure out what is best for your house. Maybe a central located router and a outdoor AP would be better....all depends on where you have ethernet jacks.

This is actually a very complex problem people make their whole career wifi design and installation in business.
Thanks for the info. I will stay with my current set up using different SSIDs. This way , with a little inconvenience, I definitely know that I am connecting to the best signal.
 

OrlyP

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Thanks for the info. I will stay with my current set up using different SSIDs. This way , with a little inconvenience, I definitely know that I am connecting to the best signal.
You can still keep the same SSID for both APs. You just need to cycle the WiFi button on your device and it should choose the stronger signal when comes back up.