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5GHz NA-Mixed?

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Paradise

Occasional Visitor
Hi,

i know you should avoid mixing g&b and N.
But i see i have NA-Mixed in the 5GHz settings.
Does the same rule apply here?

I have:
Mixed
A-Only
NA-Mixed
N-Only (5GHz)

Whats the difference between Mixed and NA-Mixed?
And why is in the 5GHz settings only behind N-Only the 5GHz in brackets?
 
Hi,

i know you should avoid mixing g&b and N.
But i see i have NA-Mixed in the 5GHz settings.
Does the same rule apply here?

I have:
Mixed
A-Only
NA-Mixed
N-Only (5GHz)

Whats the difference between Mixed and NA-Mixed?
And why is in the 5GHz settings only behind N-Only the 5GHz in brackets?

This is from the DDWRT wiki:

Wireless Network Mode

Available Settings: Varies by device. Some of the common ones are...
##Disabled
##Mixed
##B-Only
##G-Only
##BG-Mixed
##NG-Mixed
##A-Only
##N-Only
##N-Only (2.4 GHz)
##N-Only (5 GHz)
##NA-Only
##NA-Mixed

Default Setting: Mixed
Recommended Setting: Depends on what exactly your trying to do with the device.

The help file says...
## If you wish to exclude Wireless-G clients, choose B-Only mode. If you would like to disable wireless access, choose Disable.


Note : when changing wireless mode, some advanced parameters are susceptible to be modified ("Afterburner", "Basic Rate" or "Frame Burst").

How it works:

In Mixed mode, dd-wrt routers are able to offer various wifi network types (B, G and N) at the same time from a single 2.4GHz radio. 802.11n transmission is always embedded in an 802.11a, for 5GHz radios, or 802.11g for 2.4GHz radio transmissions. This is called Mixed Mode Format protection (also known as L-SIG TXOP Protection).

For additional info, check the DDWRT Wiki here: http://www.dd-wrt.com/wiki/index.php/Advanced_wireless_settings
 
The whole thing is confusing and the question is not only DD-WRT related.

In Wikipedia i read:
Using the 5 GHz band gives 802.11a a significant advantage, since the 2.4 GHz band is heavily used to the point of being crowded.
Yes 5 GHz is not crowded - but here the sentence talks about the specifications and the frequency.

Hard to explain what i mean but from the sentence it sounds like only "5GHz A"
has advantages and "5GHz N" not.

If i'm reading it right here: http://forums.smallnetbuilder.com/showthread.php?t=2506
then "5GHz a+n" has the same drawbacks like "2.4GHz n+b+g".

I wonder if there are any 5GHz a-only devices/clients?
 
The whole thing is confusing and the question is not only DD-WRT related.

In Wikipedia i read:

Yes 5 GHz is not crowded - but here the sentence talks about the specifications and the frequency.

Hard to explain what i mean but from the sentence it sounds like only "5GHz A"
has advantages and "5GHz N" not.

If i'm reading it right here: http://forums.smallnetbuilder.com/showthread.php?t=2506
then "5GHz a+n" has the same drawbacks like "2.4GHz n+b+g".

I wonder if there are any 5GHz a-only devices/clients?

Yes, there are 5ghz 802.11a clients still out there. But they are largely obsolete at this point. The 802.11a protocol was first issued by IEEE in 1999, and products were released sometime in the early 2000's. The advantage to 11a at that time was that prior to its introduction, wireless was restricted to the 2.4ghz frequencies and they were becoming overcrowded and offered slower speeds (at the time only 11b devices were around, and they were limited to 11Mbps). So the ability to use the less crowded 5ghz band, and the higher potential throughput of up to 54Mbps (theoretical) with 11a was an advantage over 11b. But 802.11a also had significant drawbacks: It was more susceptible to interference, and it's range (because it used the higher frequency 5ghz band) was more limited than the lower frequencies of 2.4ghz (a good example of how lower radio frequencies travel farther than higher ones can be found with cars that have heavy "bass" boosters...you can hear them coming from blocks away even if you can't hear the rest of the music...this is because lower frequencies travel farther than higher ones...radio waves work the same way). And when 802.11g was introduced a few years later, with its greater range (because it used the lower frequencies of 2.4ghz) and the same maximum speed of 54Mbps as 802.11a, the 802.11a standard eventually lost whatever advantages it provided, and except for specialized uses (such as with medical devices or particular industrial applications), 802.11a has mostly faded into oblivion, particularly now that 802.11n and 802.11ac provide much, much higher throughputs on the same 5ghz channels used by 802.11a devices.

The link you're reading about "mixing" devices simply explains backwards compatibility and what routers do to insure that compatibility at the expense of newer protocol functionality.

What occurs is that when you actually connect devices that are using an older and slower 802.11 standard, it will slow down even your newer, faster 802.11 standards devices to the maximum speed of the older standard protocol. And this happens with devices on both 2.4 or 5ghz bands.

For example, if you have an 802.11n device connected to your router on the 2.4 ghz band, and then connect an older, slower 802.11g device, this will limit your maximum speed and throughput on the channel on which both devices are connecting to the theoretical maximum speed that the older and slower 802.11g device is capable of using. This will therefore limit your newer, faster 802.11n device to the maximum speed that can be achieved by the older 11g device (or 54Mbps).

Same principle applies to 5ghz devices. If you've got an 802.11ac dual band router and connect an 802.11a (not "ac" but "a") to the 5ghz channel, you've now limited the maximum speed of any 802.11ac or 802.11n devices also connected to that 5ghz channel to the theoretical maximum speed of 802.11a (again, 54Mbps).

So the particular settings you enable on your router will affect which devices can connect and will ultimately affect the speed of your fastest devices in a downward manner. And that's what the DDWRT settings wiki attempts to explain.
 
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Yes, there are 5ghz 802.11a clients still out there. But they are largely obsolete at this point. The 802.11a protocol was first issued by IEEE in 1999, and products were released sometime in the early 2000's. The advantage to 11a at that time was that prior to its introduction, wireless was restricted to the 2.4ghz frequencies and they were becoming overcrowded and offered slower speeds (at the time only 11b devices were around, and they were limited to 11Mbps). So the ability to use the less crowded 5ghz band, and the higher potential throughput of up to 54Mbps (theoretical) with 11a was an advantage over 11b. But 802.11a also had significant drawbacks: It was more susceptible to interference, and it's range (because it used the higher frequency 5ghz band) was more limited than the lower frequencies of 2.4ghz (a good example of how lower radio frequencies travel farther than higher ones can be found with cars that have heavy "bass" boosters...you can hear them coming from blocks away even if you can't hear the rest of the music...this is because lower frequencies travel farther than higher ones...radio waves work the same way). And when 802.11g was introduced a few years later, with its greater range (because it used the lower frequencies of 2.4ghz) and the same maximum speed of 54Mbps as 802.11a, the 802.11a standard eventually lost whatever advantages it provided, and except for specialized uses (such as with medical devices or particular industrial applications), 802.11a has mostly faded into oblivion, particularly now that 802.11n and 802.11ac provide much, much higher throughputs on the same 5ghz channels used by 802.11a devices.

The link you're reading about "mixing" devices simply explains backwards compatibility and what routers do to insure that compatibility at the expense of newer protocol functionality.

What occurs is that when you actually connect devices that are using an older and slower 802.11 standard, it will slow down even your newer, faster 802.11 standards devices to the maximum speed of the older standard protocol. And this happens with devices on both 2.4 or 5ghz bands.

For example, if you have an 802.11n device connected to your router on the 2.4 ghz band, and then connect an older, slower 802.11g device, this will limit your maximum speed and throughput on the channel on which both devices are connecting to the theoretical maximum speed that the older and slower 802.11g device is capable of using. This will therefore limit your newer, faster 802.11n device to the maximum speed that can be achieved by the older 11g device (or 54Mbps).

Same principle applies to 5ghz devices. If you've got an 802.11ac dual band router and connect an 802.11a (not "ac" but "a") to the 5ghz channel, you've now limited the maximum speed of any 802.11ac or 802.11n devices also connected to that 5ghz channel to the theoretical maximum speed of 802.11a (again, 54Mbps).

So the particular settings you enable on your router will affect which devices can connect and will ultimately affect the speed of your fastest devices in a downward manner. And that's what the DDWRT settings wiki attempts to explain.

Well, no, you don't limit the faster devices to the speeds of a slower standard. You are sharing airtime, so it WILL slow things down as the router transitions between clients. If one client needs 5Mbps, it is going to take up a lot more air time if it is being transmitted at 54Mbps than if it was being transmitted at 150Mbps, or 300Mbps or 867Mbps. This leaves less airtime for the faster devices, limiting their performance.

What you also have is legacy things, like slower beacon frames, larger pauses between packets (guard interval), etc. that CAN bleed over in to the faster devices potentially limiting performance a bit, even if NO legacy devices are connected. Simply by virtue of having the ability for slower devices being able to connect to your network, some of the old cruft has to continue to operate, even if newer standards don't require it.

Newer routers tend to be better at this stuff than older routers in my experience. Older ones it deffinitely benefited to disable compatibility with older standards. I'd see an easy 10-15% boost by disabling 11b/g and similar supported bits for those standards on my 11n devices on some older 11n routers. On my newer 11n/11ac routers, I see relatively little performance increase (within the margin of error in testing really, but it COULD be 3-4%), but at the same time, I don't want older devices connecting to my network at all potentially slowing things down.
 
Well, no, you don't limit the faster devices to the speeds of a slower standard. You are sharing airtime, so it WILL slow things down as the router transitions between clients. If one client needs 5Mbps, it is going to take up a lot more air time if it is being transmitted at 54Mbps than if it was being transmitted at 150Mbps, or 300Mbps or 867Mbps. This leaves less airtime for the faster devices, limiting their performance..

Just one minor quibble with this, and that is that when both legacy and newer devices are connecting at the same time, it will slow down the faster devices; so yes, they are limited to the speed of a slower standard when connecting at the same time. But generally you are also correct about the principal of shared airtime too. Thanks for bringing that up. Nevertheless, I find that there is a performance hit with is a lot greater than 3-4% when legacy devices are connected to the same channels on 2.4ghz. But like you I just disable the slower standards because I don't want that stuff connecting to my network. If I truly must have an older device connect, I try to use a bridge and even if it's a fast 100 internet LAN port, if I bridge to it using 5ghz and an 80Mhz wide channel, it's not as bad as connecting with b/g.
 
Yes, WHEN THEY ARE connected. When they aren't, it is minor to have a lot of the legacy cruft still enabled on newer APs. Which were the hits I was talking about.

Have an 11b device connected and streaming data and you can easily see a 40-80% performance hit on your faster devices.

That isn't because the faster device is at a much lower modulation rate, it is because of the airtime being taken up. The AP will immediately shift to the higher modulation rate to talk to the newer device when it is the other devices turn to Tx/Rx. It is not forcing the newer device to use an older standard, it is principally about how much air time the slow device uses, which is going to be a lot more since it is running at a lower data rate. If it was at a higher data rate it could spend less time talking/receiving to get the same amount of data, leaving more airtime for fast devices.

That said, I'll admit if there are older devices that need RTS/CTS to operate, that will force newer devices to also function with RTS/CTS even when it is their time to talk/receive (at least to the best of my knowledge), which does have an overall performance hit, but they are still using the much higher modulation rates.

That said, this is again ONLY if there are legacy wireless devices active on the network. If there aren't, then legacy compatibility functionality has a very tiny performance hit, when legacy devices are active it can increase that hit and if they are actively streaming data the hit can be huge.

That's why friends don't connect their legacy devices to other friend's WLANs. Also why I never keep legacy compatibility enabled unless I am not able to disable it. I don't want your legacy junk connected to my network if you are a guest and I certainly don't have any, nor will I ever, so no point in keeping compatibility there (and I don't need to worry about legacy compatibility with neighboring networks. My closest neighbor network is >35dB lower in signal strength than mine at my weakest spot).
 
For 5GHz, I would just run in Mixed Mode, as there isn't any benefit to running N-Only, and there isn't a lot of 11a gear out there...

Not only that, but even if one has 11a gear, there isn't the cruft associated with mixed mode in 5Ghz that one has down in the 2.4GHz band, so a mix of 11a/11n/11ac clients on an 11n/11ac Router/AP doesn't have the impact of what one sees with 11b/11g/11n downstairs in 2.4GHz.

sfx
 
For 5GHz, I would just run in Mixed Mode, as there isn't any benefit to running N-Only, and there isn't a lot of 11a gear out there...

Not only that, but even if one has 11a gear, there isn't the cruft associated with mixed mode in 5Ghz that one has down in the 2.4GHz band, so a mix of 11a/11n/11ac clients on an 11n/11ac Router/AP doesn't have the impact of what one sees with 11b/11g/11n downstairs in 2.4GHz.

sfx
^
|
|

Completely agree with this.
 
That's why friends don't connect their legacy devices to other friend's WLANs. Also why I never keep legacy compatibility enabled unless I am not able to disable it. I don't want your legacy junk connected to my network if you are a guest and I certainly don't have any, nor will I ever, so no point in keeping compatibility there (and I don't need to worry about legacy compatibility with neighboring networks. My closest neighbor network is >35dB lower in signal strength than mine at my weakest spot).

In urban/suburban areas, it's always best to run in mix-mode (b/g/n and a/n/ac) - 11n greenfield operation in 2.4GHz can impact adjacent WLAN's (and impacted by them) by going into Protected Mode operation. Which incurs a fairly significant penalty.

This is why Greenfield (N-only) was removed from 11ac BTW...

sfx
 
I am aware.

That is why I said I don't have to worry about compatibility with neighboring networks as they are all massively lower signal strength than my own network due to large distance. Closest house is >100ft away, second closest is >200ft away and the 3rd closest is over 300ft away. The strongest network rings in at -85dBm inside of my house if I stand by the window, the others generally are not visible at all, or InSSIDer can sometimes pick them up on my laptop in the -92 to -94dBm range if I stand in the right spot in my house...making my network roughly 20,000 times stronger signal strength in the LOWEST signal strength spot for my network in my house compared to the strongest for them at that location and it averages closer to 100,000 times stronger signal strength if not higher. By converse, their networks in their house should be tens of thousands of times stronger if not more. So interference is never going to happen. You've gotta be approaching 20dB of signal strength difference for that to possibly be a concern in anyway, and I am not even coming close to 30dB.

Even my outdoor AP sees at most 25dB of cochannel interference from my neighbors networks if I am near the edge of my property nearest the interefering network (my closer neighbors network is stronger than that if I stand near their house, but it isn't cochannel and my outdoor AP is still about 20dB higher signal strength). Over most of my property I have a good 30-40dB higher signal strength than my neighbors (and in their houses, odds are good that their networks are still going to be at least 20-30dB higher signal strength than my outdoor AP...because much closer to their router and walls in the way of mine).
 
My Cisco WAP321 has settings for 11an and 11n only in 5GHz range.

Greenfield (802.11n) Mode was removed in 802.11ac - but in 5GHz, if you don't have 802.11a clients, might as well use it, but leaving it in mix-mode won't hurt performance...

In 802.11ac - best to leave in mixed-mode for 5GHz... best performance for all clients, mixed or not...
 
I never was able to connect my fathers Lumia to the 11n and my fathers Motorola Xoom tablet did also not really work.
I switched now from N-Only to NG-Mixed for 2.4GHz and NA-Mixed for 5GHz and now it works.

Is there a reason that there is no NB-Mixed?
 
I wish these routers would start coming with AC Only. Not liking the mixed mode on AC routers as mixed mode has A,N and AC. I mean really are than any A or B devices still being used out there?
 
I have to say I have tested wireless 802.11a on my old laptop and the speed seems fine. I would not use b mode but a mode seems fine for web browsing. I may not bother to upgrade my wireless on my old laptop. I mainly use a wired connection anyway on my laptop.

I have 22 networks on 2.4GHz around me. I have been testing 5GHz and I think I am going to run 5GHz mixed 802.11an mode only now. Everything seems faster. Coverage will work in my house with 2 Cisco WAP321 wireless APs. My only problem now is outside so I will need to rethink my setting area in my back yard.


I know 802.11a mode is only 54Mbits on 5GHz but seems much faster than a 300MHz 2.4GHZ connection here at my house. I guess the 22 surrounding networks have a negative impact on my felt wireless speed. My wife’s iPad air seems twice as fast web browsing using 5GHz. It makes her really happy so I have made the switch to 5GHz today.
 
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Is that onlt 11a on your laptop? If the iPad is an iPad 3 or newer, it IS twice as fast. Apple products are 20MHz only in 2.4GHz, but can utilize 40MHz in 5GHz (except for the iPhone 4 and iPad 2, which are 65Mbps in 5GHz also, but the iPhone 5, 5s are 150Mbps as are the iPad 3 and 4. The Air maybe have moved to dual stream adapter, I don't remember and the iPhone 6/6+ and Air 2 can do 150/433Mbps depending on 11n or 11ac in 5GHz, though the Air 2 might be 300/867Mps in 5GHz, not sure).
 
I wish these routers would start coming with AC Only. Not liking the mixed mode on AC routers as mixed mode has A,N and AC. I mean really are than any A or B devices still being used out there?

From an IEEE 802.11ac perspective, there is no such thing as "AC Only" mode - AC is always mixed mode operation.

Lessons learned from 802.11n Greenfield problems in the field..

sfx
 
Is that onlt 11a on your laptop? If the iPad is an iPad 3 or newer, it IS twice as fast. Apple products are 20MHz only in 2.4GHz, but can utilize 40MHz in 5GHz (except for the iPhone 4 and iPad 2, which are 65Mbps in 5GHz also, but the iPhone 5, 5s are 150Mbps as are the iPad 3 and 4. The Air maybe have moved to dual stream adapter, I don't remember and the iPhone 6/6+ and Air 2 can do 150/433Mbps depending on 11n or 11ac in 5GHz, though the Air 2 might be 300/867Mps in 5GHz, not sure).

5GHz for iOS devices:

iPad 1, 2, 3 - single stream, narrow channels, a/n
iPad 4 - single stream, narrow channels a/n # iPad4 might support wide channels, but IIRC they don't, as it was basically a rush job to get the A6X and Lightning connectors, otherwise skin job on the iPad3

iPad Air - dual stream, wide channels, a/n
iPad Air2 - dual stream, wide channels, a/n/ac

iPad Mini - single stream, wide channels, a/n
iPad Mini2 (Retina), dual stream, wide channels, a/n
ipad Mini3 - dual stream, wide channels, a/n

iPhone 5 - single stream, wide channels, a/n
iPhone 5s - single stream, wide channels, a/n
iPhone 6/6+ - single stream, wide channels, a/n/ac

iPod Touch 5th Gen - single stream, wide channels, a/n

Apple TV 2nd/3rd Gen - single stream, narrow channels, a/n

All are narrow channels in 2.4Ghz, the Air/Air2/Mini2/Mini3 are dual stream
 
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