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My router can have different SSIDs for 2.4 and 5 GHz and I'm not sure if it's better to have the same SSID or not.

Initially I put the same network but I got confused when the MacBook Pro displayed me two networks with the same name, an I was not able to distinguish between then.

So the next step was to configure two networks, "home" and "home-slow".

I would like to know what are the pros/cons for these configs.

Note, I do have a Cisco E4200 router, configured:

  • 5GHz - SSID "home" - Mixed - Auto 20 MHz/40MHz - Auto-DFS
  • 2.4GHz - SSID "home-slow" - Mixed - Auto 20 MHz/40MHz - Auto

Note, iPhone4 and HTC Desire HD do not see the 5GHz network, only the 2.4 one, not sure why. MacBook Pro seems to detect both of them.

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Are they really different speeds, or does it not really matter as your external speed is too low to saturate the routers? – soandos Nov 28 '11 at 21:28
    
DD-WRT lists this as a 'work in progress'. Be sure to check up from time to time to see if it gets added. – earthmeLon Nov 28 '11 at 21:48

10 Answers 10

up vote 62 down vote accepted

Most wireless stacks do not consider these networks to be different to each other, so 2.4GHz has the same weighting as 5GHz.

If this isn't important to you, then keeping the SSIDs the same will mean it will pick whichever it sees first.

If you keep the SSIDs different, it means that you can prioritise 5GHz over 2.4GHz by adding both to your Wi-Fi connections, and saying that one is better than the other.

Note that 5GHz is not inherently faster than 2.4GHz. They both have the same theoretical maximums, 150 megabits per second (single radio chain), 300 megabits per second (two radio chains and two spacial streams), or 450 megabits per second (three radio chains and three spacial streams). However because the 5GHz frequency band is less crowded, there is more chance that the AP can get a full 40MHz band of radio to carry data.

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19  
His MacBook Pro will differentiate. Macs prefer 5GHz at higher signal strengths for best performance, and prefer 2.4GHz at lower signal strengths for best range. – Spiff Nov 28 '11 at 21:54
11  
Yes, 5GHz tends to be faster, but 2.4GHz has better range. If you use the same SSID then your client can automatically switch from 5 to 2.4 when it gets too far from the AP. The same thing can be achieved with different names, but then you have to configure both. – Tom Dec 29 '12 at 18:33
1  
What about setting each frequency to operate on different combinations of standards? My 880L allows me to set 5GHz as AC only, AC + N etc. Will having multiple standards supported on different frequencies affect performance? – square_eyes May 25 '15 at 0:11
    
This answer may be outdated. I'm reading from a lot of sources that many (most?) devices will pick a "best" frequency, not simply "whichever it sees first". – Drew Dormann Jun 9 at 18:54
    
@DrewDormann Even when this question was answered, there were stacks that would choose "best". But it remains true that what you consider best, and what it considers best may differ. Having them separate keeps the control in your hands. – Paul Jun 12 at 14:00

If you have high quality Wi-Fi client devices, it's best to use the same SSID for both bands so your clients will automatically roam to the band that suits their needs best.

If you have low-quality Wi-Fi client devices, you might need to second-guess their band-choice decisions, so you might want to have separate SSIDs.

Your MacBook Pro should not have shown you two networks with the exact same name, unless you had accidentally configured two different security types for the two networks. Or maybe you thought you had configured the exact same name for both bands, but you'd accidentally put a space at the end of one of the names and didn't notice.

Your iPhone 4 doesn't have a 5GHz radio, which is why it can't see your 5GHz network. I suspect the same is true of your HTC Desire HD.

I recommend that you leave your 2.4GHz network set to 20MHz-only. Using 40MHz in 2.4GHz doesn't leave enough room for other uses of the band, such as Bluetooth. All of Apple's N-capable gear limits itself to 20MHz operation in 2.4GHz (even if the third-party Wi-Fi AP is configured to allow 40MHz operation in 2.4GHz), in order to leave room for Bluetooth. So your MacBook Pro is only going to use 40MHz-wide channels in 5GHz.

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I think I found a solution for Androids that prioritize the 2.4 GHz Wi-Fi band over the 5 GHz band with the same SSID if you access a dual band router at home for example. If both bands have the same SSID find out which band your Android device is currently connected to using the free inSSIDer app. My was connected to channel 6 instead of channel 161 (my desired 5 GHz channel). Move to a location where you can confirm that you are connected to the 2.4 GHz band (hit the refresh button as needed on the top of inSSIDer to update) When you verify that you are connected to the 2.4 GHz band, go back to your Wi-Fi settings, you will see your SSID twice with the top one being the 2.4 GHz connection select that and select Forget.

This is better than having to choose the 5 GHz band only setting in advance settings as there will be many other places where you need to connect to both bands. Now I get great Wi-Fi speeds at home instead of competing against the crowded 2.4 band at home. Hope this helps.

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inSSIDer doesn't seem to be free – Daniel Serodio Aug 20 '14 at 3:29
    
It is free `till 3rd version, 4th is not. – Pax0r Sep 8 '15 at 21:25

Depending on your network card, you may be able to configure it in the driver. For example, in Windows 8:

enter image description here

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This is good for people like us who have ac but not for those who still use n for both 2.4 and 5Ghz of course. Isn't there also a way to disable wireless n to pretty much achieve the same results? – mchid Oct 15 '15 at 23:37

But even with all of this, one thing to bear in mind is that the client is making the decision as to which SSID it connects to. So even if you have 2.4Ghz and 5Ghz with the same SSID, once the client has connected to whatever channel it decides it wants to first, in most cases it will hold on to that SSID for dear life. Certainly Apple devices, they will hold on to an SSID until it barely has any signal at all. For Android there are a number of APPS that you can install that will manage this for you, by simply selecting the strongest SSID Access Point. For Apple there are no APPS available, so trial and error seems to be the best option!!

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Unless you force your client device to choose a specific SSID, it will usually choose the one with the strongest received radio signal. So, if you use the same SSID for both 2.4G and 5G, more than likely the 2.4G radio, which has a longer range and passes through walls and floors better, will be the stronger signal.

I set up separate SSIDs with names that identify which frequency is used, so I know which radio frequency I'm using.

Regarding which channel to use, it's a fallacy to assume that the highest channel is the best. In fact, as the frequency increases, the attenuation increases as distance from the radio increases, so it's better to use the lowest possible frequency. Also, with 5G, the lowest four channels are power limited (per FCC) so they don't interfere with other devices using those frequencies (airport radar?). So, the lowest 5G frequency to use is actually the fifth lowest channel.

-rb

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Short & Sweet!

I keep mine Separate. Home_2.4Ghz & Home_5GHz. The devices that can support 5Ghz I want them utilizing 5Ghz. The devices that only support 2.4GHz I want them on 2.4Ghz. I do not want my router choosing for me. In addition I keep both wireless settings at 40Mhz doubling up on the speed and put them on the highest channel for the best performance. One thing to keep in mind 2.4Ghz can reach further than 5Ghz. So if you have a 5Ghz device and it is far from the router use 2.4Ghz.

C-ya!

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3  
This comment is formed as personal opinion. It could be improved by focusing on facts that would be apply to the question rather than personal preference. – Mark Stosberg Feb 2 '15 at 20:48
    
As well as some of the facts are not verifiable. Putting it on the highest channel only improves performance if other things in the area are on lower channels. Channel 1&11 are both at the end of the spectrum and work equally well as long as all other devices are in the mid range. No throughput is gained either way. – Lofful Oct 13 '15 at 22:29

It would definitely make sense to use one (1) SSID for both 2.4 and 5 GHz band and just allow your devices (smartphones, tablets, laptops, etc) select the appropriate band.

For Android devices (with Kit Kat or Lollipop) there is actually an 'Advanced' setting under WiFi to select which band you want to use: Auto, 2.4 GHz or 5 GHz. For this I always select 5 GHz to get the fatter and fastest band with my AC router.

My iPod touch and Dell laptop would only connect to the 2.4 GHz band (20 MHz).

The desktop computer connects wirelessly via the 5 GHz (20/40/80 MHz) thru its USB AC dongle.

Having different names for the SSID 2.4. GHz and 5 GHz is helpful if you really want to separate your connected devices. I used to have that setup before.

But the advantage of just having one (1) name for SSID avoids my confusion as to which name to use for 2.4 GHz or 5 GHz. I just allow my devices pick the band it is capable of.

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My experience is that you should not give the different bands the same SSIDs unless you have two dual band routers and set each router with one particular channel for each band with the same name. Example below:

router 1: 2.4ghz TwoFourG set to channel 1 5.0ghz FiveOh set to channel auto *if in complex put next to end of home and external wall and reduce power output for 25%

router 2: 2.4ghz TwoFourG set to channel 6 5.0ghz FiveOh set to channel auto *put next to opposite end of home and reduce power output for 25%

router 3: 2.4ghz TwoFourG set to channel 11 5.0ghz FiveOh set to channel auto *put center of home (on center of 2nd floor if 2 levels) and reduce power output for 25%

Set 2.4 channels because the spectrum range is 11 channels but only 3 non-overlapping channels (1,6,11) of 5 frequencies apart give best chance of

2.4ghz are saturated but give more sustainability at greater distances but I found I can resolve disconnect and interference issues with multiple routers. The same applies to 5.0ghz but I don't specifiy channels as there 23 non-overlapping channels and far less devices interferring and 5g doesn't have to adhere to the Coexistence Neighbor of 40Mhz which prevents for Wireless 2.4ghz in high populated zones (apartments, condos, etc) from getting jammed.

I'm not an engineer but I've been configuring SME/SMB LAN/WAN/WLAN for 17+ years.

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I would say yes, use different SSID's to differentiate. You don't want your own system to bounce between bands. Plus if you are like me and have an access point, you will have nothing but headaches trying to diagnose issues when they arise. I have found that the primary router output and access point interfere between bands if I don't isolate 2.5GHz and 5GHz. Sounds weird, but that one change saved me from continuously getting WiFi issues and not.

So get in the habit now of using an SSID for each band you have. It'll save yo headaches in the long run.

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