OK to use same SSID for 2.4 & 5 GHz?

[ags]

I'm new to wireless-n and have just setup an ASUS RT-N66U.

I've enabled both 2.4 & 5GHz radios. I've given both the same SSID, thinking that it's up to the client to figure out which to connect through. (I originally thought that the 2.4GHz band was slower and/or for .g connections and 5GHz for faster and/or .n, but I guess that's not correct - or is it?)

Is this correct, or should I have different SSIDs and explicitly connect to one or the other when pairing all client devices?

 

[r00t4rd3d]

They should be separate. Most clients will connect to 2.4Ghz cause the signal will be stronger. Different SSID and passwords for both. I label mine Asus and Asus5G.

 

[wouterv]

Technically there is no reason for different SSID's on 2.4 GHz and 5 GHz.
Clients setup to be able to connect to either of your signals will work the same, with the same or different SSID's.
It is for your own convenience to assign different SSID's, that is the only way to determine on the client side if you are connected to 2.4 GHz or 5 GHz.

For the RT-N66U the theorethical maximum speed for 2.4 GHz and 5 GHz is the same: 450 Mbps.
The maximum speed can only be obtained with 802.11n, 40 MHz bandwidth, and the client be able to utilise the 3 supported spatial streams of the router. Many clients have only 2 antenna's and hence support up to 300 Mbps, clients with one antenna support up to 150 Mbps.
The main difference between 2.4 GHz and 5 GHz is the maximum distance and the amount of neighbor disturbance.
2.4 GHz is able to cover and average house.
5 GHz is able to cover one room, maybe one adjacent room.
Due to the longer range, neighbor disturbance on 2.4 GHz is an issue, causing degradation in signal quality and throughput.
Use a program called inSSIDer to check the wireless environment and select the least occupied channel on 2.4 GHz, also the best to set the bandwidth of 2.4 GHz to 20 MHz (the last will decrease the neighbor disturbance, but will also lower the speed).

I suggest different SSID's and explicit assign clients to either 2.4 GHz or 5 GHz depending of their location and purpose.
A common advise is to use 2.4 GHz for general Internet purposes and use 5 GHz for streaming applications (which only works well if the distance is not too long).

For routers that support 802.11ac, the maximum throughput on 5 GHz is increased by using more spatial streams, using a wider bandwidth and an enhanced compession algorithm. Again, the increased throughput only works out if the client supports the applicable techniques.

 

[ags]

Thank you for the very thorough answer. Very helpful.

Many clients have only 2 antenna's and hence support up to 300 Mbps, clients with one antenna support up to 150 Mbps.

So looking at the RT-N66U there are three antennas. It's claimed to support 900 Mbps (450 Mbps on 2.4 & 5 GHz each) so that means that each antenna is supporting one "spatial stream" on each frequency (2.4 & 5 GHz). Is that correct?

Use a program called inSSIDer to check the wireless environment and select the least occupied channel on 2.4 GHz...

The default channel setting is "Auto". I presume that is what most routers in my neighborhood are configured to use. If that's the case, it seems the "best" channel at any one time is dependent on what my neighbors are doing. Selecting the "best" channel at one time may lock me in to a channel with a lot of interference at another time. It may be another incorrect presumption on my part, but I expected that by leaving the setting to "Auto", the router would negotiate with the client and choose/select the best channel with minimum interference. (but I also thought it would choose the best band (2.4/5GHz) which is incorrect).

...also the best to set the bandwidth of 2.4 GHz to 20 MHz (the last will decrease the neighbor disturbance, but will also lower the speed).

On the router admin page, there is an option to set channel bandwidth. Options are 20, 40, and 20/40 MHz. With the 20/40 setting, how is the value chosen? By the router based on interference? By the client?

They should be separate. Most clients will connect to 2.4Ghz cause the signal will be stronger. Different SSID and passwords for both.

I now realize that by using the same name for 2.4 and 5 GHz radios. I have no idea which I've actually connected to. (I thought the "best" would be selected by the router). By using different names, I can see which radio a client is connected to. AFAIK, none of my clients (MacBook Air, for instance) give me a way to specify "connect to the strongest radio in range", but instead I set a preferred order of connecting. As long as the first specified is in range, it will be used. So there is no way for me to setup my wireless network to automatically connect on the "best" radio (strongest, least interference) in use by my router. Is that true?

What is the benefit of using a different password for the two different radios?

 

[r00t4rd3d]

By default most wireless adapters try to connect to the strongest signal, there is no settings normally to alter it.


I like using different passwords just to be thorough in keeping the two signals separate. It also allows the router admin to dictate to other users what signal can be used, NO 5GHZ FOR YOU!

 

[wouterv]

So looking at the RT-N66U there are three antennas. It's claimed to support 900 Mbps (450 Mbps on 2.4 & 5 GHz each) so that means that each antenna is supporting one "spatial stream" on each frequency (2.4 & 5 GHz). Is that correct??

Correct, again that is the router side which is one end of the wireless connection. The final maximum data rate depends on the match between router and client.

The default channel setting is "Auto". I presume that is what most routers in my neighborhood are configured to use. If that's the case, it seems the "best" channel at any one time is dependent on what my neighbors are doing. Selecting the "best" channel at one time may lock me in to a channel with a lot of interference at another time. It may be another incorrect presumption on my part, but I expected that by leaving the setting to "Auto", the router would negotiate with the client and choose/select the best channel with minimum interference. (but I also thought it would choose the best band (2.4/5GHz) which is incorrect).?

In theory yes, practical not. The best is to manual select the least occupied channel and frequently (weekly?) monitor your situation again and adapt the channel if required.

On the router admin page, there is an option to set channel bandwidth. Options are 20, 40, and 20/40 MHz. With the 20/40 setting, how is the value chosen? By the router based on interference? By the client??

Yes the router will scale down depending on interference. In crowded areas it is the best to manual select 20 MHz, by this (together with the manual channel selection) you keep control.

I now realize that by using the same name for 2.4 and 5 GHz radios. I have no idea which I've actually connected to. (I thought the "best" would be selected by the router). By using different names, I can see which radio a client is connected to. AFAIK, none of my clients (MacBook Air, for instance) give me a way to specify "connect to the strongest radio in range", but instead I set a preferred order of connecting. As long as the first specified is in range, it will be used. So there is no way for me to setup my wireless network to automatically connect on the "best" radio (strongest, least interference) in use by my router. Is that true??

Again, manual selection is the best, I have a PC here that is setup with 5 GHz as preferred and 2.4 GHz as second. In close proximity of the router it selects 5 GHz. Once moved far enough away it fails over to 2.4 GHz, but it will never fail back again to 5 GHz.

What is the benefit of using a different password for the two different radios?

None, unless you like the argument of r00t4rd3d
Most users set different SSID's and equal pre-shared keys.
Be aware that it is strongly suggested to uses alphanumeric characters only (Aa to Zz and 0 to 9, no spaces and no odd characters such as +@#$%) for the SSID's and the pre-shared keys.

 

[sm00thpapa]

I use different SSID's but use the same password for both and have no issues.

2.4 Asus

5G Asus_5G

 

[aaronwt]

I'm new to wireless-n and have just setup an ASUS RT-N66U.

I've enabled both 2.4 & 5GHz radios. I've given both the same SSID, thinking that it's up to the client to figure out which to connect through. (I originally thought that the 2.4GHz band was slower and/or for .g connections and 5GHz for faster and/or .n, but I guess that's not correct - or is it?)

Is this correct, or should I have different SSIDs and explicitly connect to one or the other when pairing all client devices?

I've been running identical SSIDs on 2.4Ghz and 5Ghz on multiple APs for years. Most of my wireless devices that are 5Ghz capable grab the 5Ghz first and then will choose 2.4 Ghz if needed. Although the highest signal strength is the main priority. But I've had no problems doing this over the years with multiple identical SSIDs from multiple APs.

Tonight I just added an Rt-N65U(I got a sweet deal on a new one for $60 shipped from ebay) in AP mode to the mix to replace a DLINK AP I was using. I am also using an RT-N56U in AP mode and an RT-N56U in router mode with all three using both 2.4 and 5Ghz with multiple identical SSIDs.

 

[Kris404]

I have used the same name for both bands in Airport Extreme for years without any issues.

But, I would recommend different SSIDs with the same password to ensure clients connect to the intended band.

There is no practical advantage to using the same name; it's not like the throughput from both bands is getting aggregated or anything.

 

[TonyH]

Hi,
Let's be simple and logical, would it be nice if two houses have identical address?

 

[Kris404]

Hi,
Let's be simple and logical, would it be nice if two houses have identical address?

Yes but only if I can join them together to make one big house

But that technology does not exist for wireless yet

 

[aaronwt]

Hi,
Let's be simple and logical, would it be nice if two houses have identical address?

It's more work to have two separate SSIDs. IN my experience since 5Ghz devices grab 5Ghz first, by making both SSIDs the same, they will fall back to 2.4Ghz if they need to. By only having one SSID it makes things simpler. I only need to have one SSID to enter and one key and I just duplicate that in all my APs for both 2.4 and 5Ghz(Although I do have a guest SSID, but that is for visitors). I don't care which Ap my devices connect to as long as it has the strongest signal. And if the signal drops in on AP for some reason, the devices will automatically connect to another one.

 

[L&LD]

More work to have two separate ssids, okay.

The band the client connects to is important; signal quality is secondary (throughput is king).

Setting up a new router with an Intel AC7260 card running driver version 16.10; the 2.4GHz band would show 95% in inssider through a floor, 4 or 5 walls (depending which way the signal might bounce and about 50 feet away to the router (RT-AC68U RMerlin 374.40 Alpha 4 build).

https://downloadcenter.intel.com/Se...ductProduct=Intel®+Dual+Band+Wireless-AC+7260


The identical position in the 5GHz band would show 25% in inssider.

The indicated connection speeds in Windows 8.1 were: 2.4GHz; 144Mbps and 5GHz; 103Mbps to 130Mbps.


Throughput was 10Mbps in the 2.4MHz band and over 21Mbps in the 5GHz band.


Yes, more work (once). But easily worth it.

 

[wouterv]

I agree with L&LD, also as I wrote before: yes, a client should pick the strongest signal. With 2.4 GHz and 5 GHz living next to each other, the 2.4 GHz signal is the strongest 9 out of 10 times.
My experience is that a client configuered for the two frequencies may initially connect to 5 GHz and yes if you move the client away it fails over to 2.4 GHz once the 5 GHz signal is too weak, so far so good. But, once the client is moved back in the range of 5 GHz, it stays nicely connected to 2.4 GHz.

My strong advise: take control yourself, separate SSID's and manually decide to connect a client to 2.4 GHz or 5 GHz.
5 GHz usually only covers one room, sometimes an adjacent room.
2.4 GHz covers an average home.
Fixed devices in good range of 5 GHz: connect these to 5 GHz.
Mobile devices that travel through your house, and clients further away of the router: connect these to 2.4 GHz.

Well, luckily there is the freedom of choice in how to setup your network, everyone to its own taste, as long as throughput and signal strenght is sufficient

 

[aaronwt]

My devices roam back and forth between APs and also between frequencies. I'll get 150Mb/s actual throughput(300Mb/s link rate) at 5Ghz and around 120 Mb/s throughput over 2.4Ghz. SO for my laptop and netbooks either one is fine for the speed. For my other wireless devices and bridges I'll notice them switching periodically even though they are stationary, but if they switch from 5Ghz to 2.4Ghz I'll see them switch back to 5Ghz at some point.

Since i get excellent throughput on 2.4Ghz and 5Ghz I really don't care which one is being used unless I need to transfer a large file like 30GB or 40GB. And in that instance I'll just connect a cable to the GigE connection in my laptops and netbooks to get 900Mb/s+ throughput for the transfers.

 

[ags]

So now that I realize that the two bands are totally separate radios and connections with no bandwidth aggregation, I am using different SSIDs but the same password since at this time I don't need to control who can and can't connect to one or the other band.

Having said that, now I'm wondering how those that have posted saying they use the same SSID can know which band they are connecting/connected to? How do you establish the initial connection (for instance, on a MacBook Air)? I would think that when you enter the SSID attempting to join the "other" band, you could be joining the existing band without knowing it (unless only one is enabled on the router during this process).

 

[wouterv]

..., now I'm wondering how those that have posted saying they use the same SSID can know which band they are connecting/connected to? How do you establish the initial connection (for instance, on a MacBook Air)? I would think that when you enter the SSID attempting to join the "other" band, you could be joining the existing band without knowing it (unless only one is enabled on the router during this process).

On most clients (e.g Windows) you cannot tell to which band you are connected (hence the advise for different SSID's as your helper).
The Wireless Log in the router can tell you though.

 

[ged]

Many clients favor 5 GHz if they can - and it is possible to change the wlan adapter settings in Windows to do the same quite easily. Thus you can use the same SSID, and get 5 GHz into use easily - with automatic fallback to 2.4 GHz when you go further away. Just take a peek at your wlan adapter settings.

I have my WLAN set up to use the same SSID for both bands, and then I have a separate "guest" SSID for 5 GHz if I ever feel a pressing need for speed. Sofar, I haven't ever used it, because in reality I get the speed I need, and if I didn't get it, then I would be out of good 5 GHz range anyway.

In my neighborhood, the 2.4 GHz band is quite crowded, but mostly with a competing signal strength of << 80 dB. In practice I cannot really tell when I'm on 5 GHz and when I'm on 2.4 GHz.

As for displaying the band you are using in Windows, just open a command prompt (cmd.exe) and type in

netsh wlan show interfaces

That will display both the band and the channel you are using. Unfortunately, the link rate displayed tends to be the maximum, and not the actual link rate. I.e. I tend to get 450 all the time.

 

[wouterv]

...
As for displaying the band you are using in Windows, just open a command prompt (cmd.exe) and type in

netsh wlan show interfaces

That will display both the band and the channel you are using. Unfortunately, the link rate displayed tends to be the maximum, and not the actual link rate. I.e. I tend to get 450 all the time.

In at least Windows 7 the above command does not tell you to which band the computer is connected, e.g. radio type 802.11n can be 2.4 GHz or 5 GHz.
Only if you are smart enough you can guess which band by looking at the channel number: any channel between 1 and 14 is usually 2.4 GHz, channels 34 and up are 5 GHz.
Anyway, my experience is that with both bands configured in Windows, with 5 GHz on top of the list, it will fail over to 2.4 GHz once the 5 GHz signal is too low, but it will never change back to 5 GHz once you are back in range (because the 2.4 GHz signal if often slightly stronger).

 

[ged]

Only if you are smart enough you can guess which band by looking at the channel number: any channel between 1 and 14 is usually 2.4 GHz, channels 34 and up are 5 GHz.

Sorry for being imprecise - that was exactly what I meant. I.e. from the channel you can derive which band is being used.

Anyway, my experience is that with both bands configured in Windows, with 5 GHz on top of the list, it will fail over to 2.4 GHz once the 5 GHz signal is too low, but it will never change back to 5 GHz once you are back in range (because the 2.4 GHz signal if often slightly stronger).

At least my experience with Intel adapters shows that if I select "prefer 5 GHz" in the adapter settings, I will mostly be on the 5 GHz band. This is a vendor setting though, so different adapters will work differently.