802.11ac bottleneck

Discussion in 'hardware' started by treehouse786, Aug 6, 2013.

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  1. treehouse786

    treehouse786 Registered Member

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    question for you network wizards.

    here is the network scenario;

    wireless router=802.11ac
    server=802.11ac compliant
    workstation1= 802.11ac compliant
    workstation2=802.11n compliant

    will the router fallback to 802.11n for all devices due to the one device on the network being 802.11n or will it separate the wireless signals to achieve the optimal wireless standard for each device?

    thank you in advance
     
  2. Bill_Bright

    Bill_Bright Registered Member

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    Since you did not tell us the model number of your wireless router so we have no clue what your wireless router supports, and no way to research the answer either. :(

    The answer, btw, depends on whether the router is a "simultaneous" dual-band", or just dual-band. Simultaneous dual-band wireless routers actually provide two wireless networks, supporting both speeds at the same time. Regular or "selectable" dual-band supports just one at a time - and therefore to support all devices, will toggle down to the lowest supported speed.

    I suggest you read the manual/specs for your wireless router. You can download it from the maker's site.
     
  3. treehouse786

    treehouse786 Registered Member

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    so its depends on the capability of the router?

    thank you Bill. thats pretty much what i wanted to know.
     
  4. Bill_Bright

    Bill_Bright Registered Member

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    Yes. And you are welcome.
     
  5. kdcdq

    kdcdq Registered Member

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    Gentlemen, I just wanted to add a bit of clarification to this thread:

    802.11n (single band) uses the 2.4ghz band for communication.
    802.11ac uses the 5ghz band only for it's communication.

    This means that a standard n-adapter can NOT interfere with 11ac bandwidth nor can it reduce 11ac speed to 11n speed.

    Now, I am not sure if the same applies to a dual-band n-adapter, because a dual-band adapter communicates on both frequencies. Looking a the specs for several current 11ac routers, it appears (to me at least) that the adapters negotiate the best speed in the 5ghz band that they can, and if this is true, the use of mixed dual-band adapters connected to the same 11ac router will not degrade 11ac performance.
     
  6. Bill_Bright

    Bill_Bright Registered Member

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    Ummm, no. Sorry but that is not correct. 802.11n supports both the 2.4 GHz and the lesser used 5 GHz bands. Support for 5 GHz bands is optional, however.

    Single band simply means one band. Dual band means the WAP (wireless access point) is able to support both 2.4GHz and 5GHz devices. Simultaneous Dual-band means both 2.4GHz and 5GHz devices at the same time.

    http://www.enterprisenetworkingplan...n-Unlocks-the-Potential-of-the-5-GHz-Band.htm
     
  7. kdcdq

    kdcdq Registered Member

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    Bill, I'm trying to clarify what I said previously.

    I have used single and dual band wireless adapters from the following companies: Netgear, Linksys, D-Link, Trendnet, and Belkin. The comments below are based on my networking experience:

    1) Every 802.11n single-band wireless adapter that I have ever used or looked at uses the 2.4ghz band for communication. If you know of or can find a single-band wireless adapter that only uses the 5ghz band, I would appreciate knowing who makes said adapter and what model number it is.

    2) Every 802.11n dual-band wireless adapter that I have ever used or looked at uses one of the two bands for communication, either the 2.4ghz band or the 5ghz. If there is a simultaneous dual-band wireless adapter on the market that can connect to and use both wireless bands simultaneously, I am not aware of it's existence.

    Example: here is a quoted FAQ about a Netgear dual-band adapter from the Netgear website:

    'When does WNDA3100 operate at 2.4GHz and when does it run at 5GHz?

    WNDA3100 will detect wireless routers/AP at both wireless frequencies. During a network scan, it will scan both frequencies to provide all wireless routers/AP in the range. WNDA3100 adapter will operate at the same frequency the wireless router it connects to. The WNDA3100 will operate at 2.4 GHz if connected to a wireless router set at 2.4GHz. If your wireless router is :) configured at 5GHz then WNDA3100 operates at 5GHz.'

    3) Routers or Access Points can be single band, dual band, or simultaneous dual band devices.
     
    Last edited: Aug 12, 2013
  8. Bill_Bright

    Bill_Bright Registered Member

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    To be sure we are on the same page, "adapters" are used by devices (computers, networked printers, NAS devices, etc.) to connect that device to wireless networks.

    Typically in wireless networking, single or dual band refers to the capability of the WAP (wireless access point). The WAP may be a stand-alone device to add wireless support to an existing Ethernet network, or more commonly today, the WAP is integrated with a router (and typically a 4-port Ethernet switch) into what marketing weenies incorrectly call a "wireless router".

    So when I said simultaneous dual band, and I was referring to the capability of the WAP to support both 2.4GHz and 5GHz devices at the same time. Sorry for any confusion.
     
  9. kdcdq

    kdcdq Registered Member

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    It took a while, but it looks like we are all singing from the same hymnal now. :rolleyes:
     
  10. Bill_Bright

    Bill_Bright Registered Member

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    Right - except we still don't know the capability of treehouse's wireless router though with only 3 attached devices, I doubt there will be any problems unless all 3 doing some serious downloading at once, and even then, the bottleneck may be the ISP and not the local network.
     
  11. kdcdq

    kdcdq Registered Member

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    Very well stated Bill.... :thumb:
     
  12. treehouse786

    treehouse786 Registered Member

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    sorry Bill for not clarifying. it was a hypothetical scenario, i have not actually bought any devices with regards to this thread, wanted knowledge for the future just in case i did take the wireless route for my new home.
     
  13. Bill_Bright

    Bill_Bright Registered Member

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    No problem - it allowed for some good exchange of information. :)

    Of course the problem with hypothetical scenarios is they call for hypothetical solutions. But then again, it is hard to be specific when just starting to learn what those specifics might be.

    Well, the problem there is advances in high-tech technologies move so rapidly that planning for the future can be a challenge, especially if we don't know what our requirements will be in the future.

    If your new home is not yet built, I sure would recommend pre-wiring it with CAT-6 Ethernet cable and avoid wireless, if possible because of the (1) exposure (you can't hide the fact you have a wireless network and computers) and (2) increased administrative (security) responsibilities with wireless. Pre-wiring is a lot easier than punching holes in walls, floors, and ceilings, and pulling cable through attics and crawl-spaces.

    In any case, at the very least, use a basic Ethernet router, even if your network consists of just one connected computer. The added layer of security even a simple, basic router provides is significant.
     
  14. agoretsky

    agoretsky Eset Staff Account

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    Hello,

    One thing to keep in mind about 802.11ac external network adapters is that many of them only have USB 2.0 interfaces, which means a theoretical maximum of 480Mbit/s (60Mbyte/s) throughput. Of course, since the USB protocol has some overhead itself, the real world speed will be lower.

    Regards,

    Aryeh Goretsky
     
  15. Bill_Bright

    Bill_Bright Registered Member

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    While true, the 11ac standard calls for a single link throughput of at least 500 megabits per second (500 Mbit/s). So, in theory, USB 2.0 would create a tiny (very tiny) 20Mbit/s bottleneck, I highly doubt any human can detect that in a blind A/B comparision.

    Still, Aryeh's point is sound. If shopping for a USB 11ac adapter (actually, for any USB device under consideration) ensure "future proofing" by getting USB 3.0.

    Of course, to take advantage of USB 3.0 performance, you must ensure the device is connected to a USB 3.0 port on your computer - assuming your computer/motherboard is new enough to support 3.0 (or you have added a PCIe USB 3.0 card).
     
  16. funkydude

    funkydude Registered Member

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  17. Bill_Bright

    Bill_Bright Registered Member

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    Glad you edited your post. My email notification showed you initially said PCI - which would create a bottleneck.

    As mentioned earlier, a PCIe card is good option but if going that route, I would get one with external antennas. The internal cards work, but we have to remember these devices are tiny radio (RF) transmitters and receivers. And RF signal strength can be greatly impacted if the antenna is located inside a metal cage. And in my mind, a metal cage is exactly what the chassis a PC case is. So get a card with external antennas.
     
  18. BoerenkoolMetWorst

    BoerenkoolMetWorst Registered Member

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    Practical USB 2.0 throughput seems to be much lower. I have not tried USB 2.0 WiFi AC adapters, but when using external hard drives connected through USB 2.0, practical transfer speeds are about 30MB/s (240Mbit/s). The hard drives read and write speed are both a lot higher so they are not the bottleneck. I've also tried this with different enclosures and connected to different machines, so this doesn't seem to be related to a specific piece of hardware either. Here are more users reporting lower practical throughput:
    http://superuser.com/questions/317217/whats-the-maximum-typical-speed-possible-with-a-usb2-0-drive

    Also:
    http://www.everythingusb.com/hi-speed-usb.html
     
    Last edited: Sep 3, 2013
  19. Bill_Bright

    Bill_Bright Registered Member

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    Well, as I have noted many times (though not in this thread), theory and real-world (practical examples) rarely see eye-to-eye, especially, it would seem, when it comes to bandwidth - like advertised gas mileage and real-world gas mileage. :(

    Still, regardless, it is pretty safe to assume that newer technologies will provide better (in theory and real-world) performance. So again, if buying a USB devices today, get USB 3.0, even if the rest of your hardware only supports 2.0. The new device will not create a bottleneck, and it will carry you further (and keep up longer) into the future.
     
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