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Babaganoosh Level 1 Level 1 (0 points)

I know that if you have a 802.11n network (populated exclusively by 802.11n devices) and then a device joins which only runs at 802.11b or g, it slows the network down to that speed (b or g). Does this also apply to n devices joining an 802.11ac network?

 

Meaning, if you have a network populated only by 802.11ac devices and you introduce an 802.11n-only device, will it slow THAT network down?


iMac (27-inch, Late 2012), OS X Mountain Lion (10.8.4)
  • Bob Timmons Level 10 Level 10 (90,810 points)
    I know that if you have a 802.11n network (populated exclusively by 802.11n devices) and then a device joins which only runs at 802.11b or g, it slows the network down to that speed (b or g).

     

    This information is not correct. Faster devices will continue to run at faster speeds. If there are a lot of slower "b" or "g" devices on the network, then the faster "n" devices might slow down just a bit, due to the bandwidth on the network being split up among all the devices.

     

    For example, if I am running two "n" devices on the 802.11 n/g/b network here, and I add two older "g" iPhones, the speed of the "n" devices is not affected at all.

     

     

    if you have a network populated only by 802.11ac devices and you introduce an 802.11n-only device, will it slow THAT network down?

     

    No, the same information as above applies. Faster devices will connect at faster speeds. Slower devices will connect at slower speeds.

  • Babaganoosh Level 1 Level 1 (0 points)

    But it's *data transfer between devices* that definitely is a problem, right? Meaning, if there is a network that runs exclusively at 802.11ac and then a N device is introduced, then no device on the network will be able to transfer data to another device at anything greater than N speeds. Correct?

  • Bob Timmons Level 10 Level 10 (90,810 points)

    But it's *data transfer between devices* that definitely is a problem, right?

    Sorry, I do not understand where you are going with this.

     

    802.11ac devices communicate with other 802.11ac devices at 802.11ac levels.

     

    802.11n devices communicate with other 802.11n devices at 802.11n speeds, etc.

     

    802.11ac devices will not be affected by other 802.11n devices or 802.11g devices on the network.

     

    if there is a network that runs exclusively at 802.11ac

    You do understand that an 802.11ac router will produce a compatible signal for ac, n, g, and b devices, correct?  Each wireless device will connect and communicate according to its own capabilities.

  • Babaganoosh Level 1 Level 1 (0 points)

    ^ I meant "a network that has only 802.11ac devices on it".

  • Bob Timmons Level 10 Level 10 (90,810 points)

    A network that has only 802.11ac devices on it will run at 802.11ac levels.  If you introduce an 802.11n device or devices, that device will connect at 802.11n levels. It will not affect the 802.11ac devices running at 802.11ac levels.

     

    I think this is the 3rd time that I've said this.

  • Azqi Level 3 Level 3 (710 points)

    I had the same concern because many years ago I had heard and understood the same thing about b/g/n WiFi networks as Babaganosh wrote. Perhaps it was a misunderstanding that has proliferated across the Internet as a strong, yet incorrect, belief.

     

    Thank you, Bob Timmons, for repeating yourself so many times. You've been very consistent with your information.

     

     

    This concern is particularly troublesome because Apple's website has footnotes that aren't as clear as Bob Timmons has been. For instance, check Apple's product webpages for both the new Airport Extreme (footnote 2) and new Airport Time Capsule (footnote 4). They both contain the following statement that would lend credence to this concern:

     

    "Speed and range will be less if an 802.11a/b/g product joins the network."

     

     

    The complete footnote, for context; I bolded the prior statement to show its place:

     

    "AirPort Time Capsule is based on an IEEE 802.11ac draft specification. Performance based on comparison with Apple’s 802.11n products. Comparison assumes AirPort Time Capsule network with 802.11ac-enabled computer. Speed and range will be less if an 802.11a/b/g product joins the network. Accessing the wireless network requires a Wi-Fi-enabled device. Actual speed will vary based on range, connection rate, site conditions, size of network, and other factors."

     

     

    That statement is not unambiguous as yours, Bob Timmons. Its statements like that one in the footnote on the product pages that appear to support the idea that all products must be the same standard, else the whole network will be reduced to and capped at the slowest standard.

     

    Admittedly, the statement does not refer to 802.11n WiFi networks. Are 802.11n devices the exception? Will those not affect the speed and range of the network?

     

    The big question is to what does "speed and range will be less" refer? Does that refer to the whole network, or just the 802.11a/b/g devices. Because 802.11n was not mentioned, that is suggestive that it's NOT only the 802.11a/b/g devices experience slower speeds and shorter ranges. Otherwise, the lack of mentioning 802.11n implies speed and range will NOT be less for 802.11n devices, which suggests 802.11n devices will experience 802.11ac speed and range. That doesn't seem possible. So, "speed and range will be less" must refer to the whole network being capped at max speed and range based on the lowest standard.

     

    I think Apple needs to rephrase that statement for clarity of whatever they were trying to say. I'm not sure what will happen to the quality of the speed and range of the whole network and for each device if devices other than 802.11ac are wirelessly connected.

     

    Until then, it would be much more reassuring if someone can provide a source to an Apple document clearing stating about the 802.11ac supported in the new Airport Extreme and Airport Time Capsule in the way Bob Timmons has stated. The manual and tech specs pages for the new Airport Extreme and Airport Time Capsule didn't seem to have the caveat in any form, and so the footnote on their Overview product pages (but not their Tech Specs page) is reviving this concern at the expense of confusion with their 802.11ac products capabilities.

  • mallanlee Level 1 Level 1 (0 points)

    Well said Azqi.  You clearly described my concern as well.  I would like to hear a response to your post from Mr. Timmons that does not repeat what he has in fact said three times already, but rather cites some real world speed testing data comparing ac speed on "pure" ac networks vs. ac speed on "mixed" networks.

  • chaicka Level 1 Level 1 (15 points)

    Previous generations AEBS have that option to statically (hardcode) set to operate in pure 802.11n mode and noticeable performance (including throughput and coverage range) gain after configuring to pure mode.

     

    Maybe I just missed it. I do not see any option in this new 6th gen 802.11ac AEBS to hardcode radio mode to operate in.

     

    Is that option available in this 802.11ac 6th gen AEBS?

  • Babaganoosh Level 1 Level 1 (0 points)

    ^ I'd like to know this as well. I have no 802.11ac gear, but I wonder if I should buy the new base station simply for the (presumably) better antenna. In that case I would like to have it operate in a pure 802.11n mode. Is this possible with the new station?

     

    Is it confirmed, or denied, that the new base station has greater range simply because of its structure? Is its antenna considered to be stronger than the old stations?

  • Bob Timmons Level 10 Level 10 (90,810 points)
    I would like to have it operate in a pure 802.11n mode. Is this possible with the new station?

     

    No

     

     

    Is it confirmed, or denied, that the new base station has greater range simply because of its structure?

     

    We have seen posts from users who confirm that the base station has better range and speed with their current devices....and....we have posts from users who deny that the new base station has resulted in any noticeable improvement on their network with their current devices.  Take your pick.

     

     

    Is its antenna considered to be stronger than the old stations?

     

     

    Apple added an additional 2.4 GHz antenna and an additional 5 GHz antenna in the new model, for a total of 6 antennas. Older versions of the AirPort Extreme and Time Capsule had a total of 4 antennas. The antennas are now located at the top of the "tower" in the new models.

     

    In theory, this should provide a bit better performance with any wireless device. In practice, this may or may not be true.

     

    No one can tell you what your results might be if you add a new AirPort. You won't know whether the product will give you better performance until you try it out in your home.

     

    If you decide to try a new AirPort, buy from Apple. You have a 14 day, no questions asked, money back guarantee.

  • polatfromfairfax Level 1 Level 1 (0 points)

    My ac airport is so slow to access to certain pages that I turn off the wifi and switch to LTE on iPhone to access the same page faster. My iPad has the same issue on ac but can't test it on lte since it is wifi only.

     

    Not good. Something is wrong.

  • Tinkered Level 1 Level 1 (0 points)

    This sounds less like a hardware problem and more like a DNS issue.  You may want to change the settings on your Airport to manually use another DNS, like openDNS, and see if that fixes the issue.

  • polatfromfairfax Level 1 Level 1 (0 points)

    Sorry...does not make sense...why would I need to change DSN setting...I did not have to play with DSN setting with the previous model of Extreme. I also do not believe that AC should require playing around with DSN settings.

     

    From my Google search, it looks like many other people are having issues. I think this one may require firmware update if not hardware...

     

    Not good...not good at all...

  • Xian Rinpoche Level 1 Level 1 (140 points)

    There's some confusion here. Bob Timmons is speaking in a more technical sense, while Babaganoosh is asking for a more real world scenario. To (hopefully) clarify (and I'm going to stay with 11n + 11g, since I'm not yet sure where 11ac improves on things):

     

    On a mixed-mode network (e.g. backwards compatible), devices capable of connecting at 11n will do so, while devices able to connect at 11g will do the same. So long as only one device is communicating with the router, things should be fine. The problem arises with "simultaneous" communication situations. While the details are perhaps overly technical, the bottom line is that a number of network "gymnastics" ensue to ensure that both devices can communicate in a stable manner, without data loss, etc. The real world implications of this can result in as much as 30% drop in speed compared to the theoretical maximum, but that tends to be extreme (e.g. one device is making constant requests for data, such as streaming, etc).

     

    I don't think Bob Timmons is saying an 11n device will experience no slowdown, just that the whole network won't "drop" to 11g (which is a common misconception).

     

    I'm no genius when it comes to 11ac, but my sense is it's no different. The network will have to "adapt" to the presence of an 11n device, thereby resulting in slower throughput than if no such device existed. That said, it will not "turn off" 11ac and run only at 11n. It'll keep 11ac going and just do what it needs to to ensure all works well.

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