Ad-Hoc and 802.11N

Discussion in 'Wireless Networking' started by JohnO, May 5, 2008.

  1. JohnO

    JohnO Guest

    A while back I posted about using 802.11A and ad-hoc for use at trade shows,
    where 2.4 was saturated and all but unusable. 802.11A is fine, but the
    hardware is difficult to locate, and probably going to get worse. I did find
    a ZyXEL AG-220 that seems to fit the bill, and its control software is easy
    to use. But I need a long-term solution that I can keep buying into the

    So, why not just use 802.11n?? (I said to myself when I realized it also
    used the 5 GHz channels.) Brilliant!

    So I picked up a pair of D-Link DWA-140 USB adapters, but the control
    software won't let me setup an ad-hoc LAN on any N (5 GHz) channels. WZC and
    the adapter's driver don't take me there either, as far as I can tell. Drat.
    So, here comes my question, finally:

    Does the current version of the 802.11n standard provide for or allow for
    ad-hoc on 5 GHz channels? Maybe I just need a different brand, one that
    allows ad-hoc on 5 GHz.

    -John O
    JohnO, May 5, 2008
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  2. JohnO

    smlunatick Guest

    I believe that the 802.11n would not be using the 802.11a signal
    channels. N is supposed to be directly compatible with 802.11g and
    802.11b. These seem to all use the 2.4GHz signals.
    smlunatick, May 5, 2008
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  3. JohnO

    Pavel A. Guest

    N works in both G and A bands, either in coexistense, or exclusive (so
    called "greenfield") mode .

    Mode of ad-hoc (for initiator side) is a proprietary driver parameter,
    located for XP
    drivers usually on the properties->advanced tab.

    As always, infractructure mode is far more reliable and easier than ad-hoc,
    so I'd
    advise to use a router and save a lot of nerve cells (or hair... whatever
    you value more).

    Pavel A., May 5, 2008
  4. JohnO

    JohnO Guest

    This is an area that's not clear to me at all, and clarity is apparently
    elusive...however the Cisco Whitepaper at the link below does say that N
    uses A's channels, as well as G's channels. Page 15 discusses migration to N
    from A.

    I'm guessing, but it seems that my inability to specify channel 52 (5 GHz)
    is simply a limitation of the control software provided by the manufacturer.
    Unless the committee tossed ad-hoc under the bus.

    -John O
    -John O
    JohnO, May 5, 2008
  5. JohnO

    JohnO Guest

    As always, infractructure mode is far more reliable and easier than
    Yeah, I know it. The application is a Remote Desktop session between a
    laptop and a mobile robot, and sales people doing presentations at random
    places. Infrastructure is a non-starter, unfortunately. That's also why I'm
    trying to get away from 2.4, you never know what's in the area, and the
    sales staff can't perform a site survey. ;-) They can't switch channels
    either, it's got to come out of the box and work wherever they may end up.
    I've been somewhat lucky with 11G on channel 1 so far, but the total
    available throughput on a single channel is so friggin low that any other
    device on the channel just about kills the connection. "Three channels is
    plenty" is right up there with 640k. LOL

    The little ZyXEL USB plug has an "AP mode" which seems to work pretty well
    in A. I can use that on the robot and the laptop can connect at full speed,
    really no different than ad-hoc when making the connection, but maybe a bit
    faster. I don't know if any other brands offer that mode.

    Is there any A channel that's least likely used? How would I choose one over
    the other?

    -John O
    JohnO, May 5, 2008
  6. JohnO

    Lem Guest

    You are correct that 802.11n provides for operation on both the 2.4 GHz
    band (like b and g) and the 5 GHz band (like a). Just because the spec
    permits such operation, however, does not mean that all products
    marketed as 802.11n do both bands or all functions on both bands.

    Not to say that this product will do what you want, but Netgear makes a
    5 GHz *only* 802.11n access point/bridge that supports ad hoc
    connections: WNHDE111

    I don't know if Netgear makes 802.11n 5 GHz USB adapters ... you'll have
    to search the Netgear site.

    Lem -- MS-MVP

    To the moon and back with 2K words of RAM and 36K words of ROM.
    Lem, May 5, 2008
  7. Hi
    The truth is that there is No future investment in any of this staff, and
    especially in Draft-N (there is No 802.11n). When the standard comes out
    whatever is sold now as draft-N might or might Not be compatible.
    A plastic/silicone gizmo that cost about $100 is hardly an investment that
    has to be guaranteed for the future. 802.11a is Not going to change and if
    it works for you buy a 802.11b/g/a Access Point land use it for the
    foreseeable future.
    If in few years, there will be something better, then you could switch.
    Jack (MVP-Networking).
    Jack \(MVP-Networking\)., May 5, 2008
  8. JohnO

    Pavel A. Guest

    I doubt that their bridge mode really works as ad-hoc (the lower diagram on
    the Overview tab).
    It can be some other protocol (WDP?) that the marketoids understood as

    The real ad-hoc is so complex that manufacturers eventually begin providing
    "AP mode" drivers for station adapters, so the station can pretend to be AP
    for other peers. From Linux this gradually leaks into Windows
    (AP mode is almost transparent for software running on such client, it only
    works better :)

    Pavel A., May 5, 2008
  9. JohnO

    Pavel A. Guest

    Duh! if you can find a client adapter that has AP driver in Windows - this
    is the best option.
    Sorry, for this IMHO you'd better consult with local specialists. AFAIK use
    of A channels is
    geo dependent and subject to local regulations. Otherwise... just try and
    find a channel where
    SNR is better.

    Pavel A., May 5, 2008
  10. JohnO

    JohnO Guest

    Sorry, for this IMHO you'd better consult with local specialists. AFAIK
    Unfortunately I can't predict where the system will be used, other than it's
    in the US. Two weeks ago Jackson MS, or someplace nearby...last week
    somewhere in the KC MO area, next week here in Michigan someplace...and
    there aren't any techs accompanying the system....just non-tech sales staff.

    I'll just pick a random channel and hope for the best.

    -John O
    JohnO, May 6, 2008
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