D-link USB adapter question

Archived from groups: alt.video.ptv.tivo (More info?)

I had a d-link dwl-122 "b" adapter connected to my TiVo and it was slow
but it worked. OfficeDepot had a D-link dwl-g120 "g" adapter on sale
for $20 after rebates so i bought one of them yesterday. It seems like
it transfers slower than the "b" adpater that I had connected. I
lookeda the box after i tried it and saw that it is version B1 and the
Tivo website says that it should be version B2. would it cause that
much of a difference between the versions? should I retrun the b1 and
try to get a b2. My other thought was to get one of the netgear wg111's
but on the internet it seems that there are several versions with
letters after the adapter. not sure which is the right one to use. any
advise would be appreciated.

thanks, Steve
6 answers Last reply
More about link usb adapter question
  1. Archived from groups: alt.video.ptv.tivo (More info?)

    I can't be 100% positive here, but I can conjecture a pretty good guess.

    Presumably your current wireless network supports "b" and "g". Most
    consumer model routers from Netgear, Linksys, and D-Link (esp. D-link), do
    NOT perform as efficiently when running in mixed mode, i.e., support 'b" and
    "g" clients concurrently. Although supported, it's with caveats (that the
    vendor usually doesn't make much mention of, for obvious reasons). First,
    when running both "b" and "g" clients concurrently, most routers will
    DOWNGRADE the "g" clients to "b" performance, simply because it can't
    actually do two things at once, it's either "b" or "g", and if a "b" client
    is transmitting when a "g" client also wants to transmit, rather than wait
    for all "b" transmissions to cease, the router simply forces the "g" client
    to run in "b" mode (or else does make it wait). Second, in order to improve
    the situation, the typical "g" router (a good one anyway, like my D-Link
    DI-624) supports something called "802.11g Only Mode". It may go under some
    other name w/ other products, but if it's there, its under the wireless
    configuration section (e.g., w/ Belkin F5D7230-4 and F5D7231-4 routers, it's
    called "54-G Only"). Why does this exist? Because when you enable this
    feature, the router doesn't have to waste processing cycles to check the
    channel for "b" traffic before transmitting every time! Instead, "b"
    clients are simply rejected, and only "g" clients accepted, and because its
    ONLY "g" clients, the router is much more efficient. Most routers level
    this feature disable by default, for maximum compatibility. But if you ONLY
    have "g" clients, it should be ENABLED for maximum performance. Secondarly,
    it's a respectable security measure, one less class of clients that can
    appropriate your wireless system!

    Granted, I'm speculating here based on very little information, BUT, most
    people don't appreciate these details wrt their low-cost, consumer-level
    routers. These routers are definitely cheap and effective, but it comes at
    a price. Yes, they support "b" and "g", but not without compromises.
    Again, most vendors don't make much of it, they simply say its supports "b"
    and "g", but once you start mixing modes on any given infrastructure, *then*
    you start to see the limitations. If this is indeed your problem, you have
    some options. For example, upgrade ALL clients to "g" and enable "g only"
    mode on the router, or perhaps buy a second router, one dedicated to "b"
    clients, the other "g" clients (naturally, you'll want to exercise
    sufficient channel separation). But the fact "b" and "g" share the same
    2.4GHz band, the situation will always be, to some degree, problematic. The
    only 100% positive means to avoid interference is to use perhaps an "a/b/g"
    router (e.g., D-Link DI-784), since the "a" uses the 5GHz band.

    HTH

    Jim


    "Steve Ball" <groucho111@sbcglobal.net> wrote in message
    news:VCc5e.20075$DW.6946@newssvr17.news.prodigy.com...
    > I had a d-link dwl-122 "b" adapter connected to my TiVo and it was slow
    > but it worked. OfficeDepot had a D-link dwl-g120 "g" adapter on sale
    > for $20 after rebates so i bought one of them yesterday. It seems like
    > it transfers slower than the "b" adpater that I had connected. I
    > lookeda the box after i tried it and saw that it is version B1 and the
    > Tivo website says that it should be version B2. would it cause that
    > much of a difference between the versions? should I retrun the b1 and
    > try to get a b2. My other thought was to get one of the netgear wg111's
    > but on the internet it seems that there are several versions with
    > letters after the adapter. not sure which is the right one to use. any
    > advise would be appreciated.
    >
    > thanks, Steve
  2. Archived from groups: alt.video.ptv.tivo (More info?)

    Comments interspersed, please see
    http://www.proxim.com/learn/library/whitepapers/parameters_802.11g_performance.pdf
    for one source of documentation:

    Jim wrote:
    > I can't be 100% positive here, but I can conjecture a pretty good guess.

    Well, your guesses have some bearing with reality, but fall short of the
    mark in several aspects.

    > Presumably your current wireless network supports "b" and "g". Most
    > consumer model routers from Netgear, Linksys, and D-Link (esp. D-link), do
    > NOT perform as efficiently when running in mixed mode, i.e., support 'b" and
    > "g" clients concurrently.

    This is true, though I want to point out (and will back up further down)
    that you are overstating the effects.

    > Although supported, it's with caveats (that the
    > vendor usually doesn't make much mention of, for obvious reasons).

    Mostly because the issue is much too complex to the casual user, and
    doesn't really matter that much to them.

    > First,
    > when running both "b" and "g" clients concurrently, most routers will
    > DOWNGRADE the "g" clients to "b" performance, simply because it can't
    > actually do two things at once, it's either "b" or "g", and if a "b" client
    > is transmitting when a "g" client also wants to transmit, rather than wait
    > for all "b" transmissions to cease, the router simply forces the "g" client
    > to run in "b" mode (or else does make it wait).

    This is sort-of true. It *is* true that only 1 device on a given 802.11
    collision domain can broadcast at once, so that when your "g" device is
    broadcasting, your "b" device must wait. But this happens even if you
    have all "b" devices or all "g" devices. What is *not* true is that
    your "g" devices are forced to transmit in "b" mode. The only change
    that your "g" device has to do is use a longer "slot" time (20
    microseconds vs. 9 microseconds) to be compatible w/ the "b" device slot
    times. This has an effect, but it's probably about a 20% penalty, not
    the 80% penalty that would be incurred from going from 54 Mbps to 11 Mbps.

    The one situation where you *may* see such a high penalty is where you
    have *2* overlapping mixed wireless collision domains (i.e. 2 wireless
    routers) on overlapping or identical channels, but this is not the
    typical residential wireless scenario, it's more of a problem for
    corporate networks.

    > Second, in order to improve
    > the situation, the typical "g" router (a good one anyway, like my D-Link
    > DI-624) supports something called "802.11g Only Mode". It may go under some
    > other name w/ other products, but if it's there, its under the wireless
    > configuration section (e.g., w/ Belkin F5D7230-4 and F5D7231-4 routers, it's
    > called "54-G Only"). Why does this exist? Because when you enable this
    > feature, the router doesn't have to waste processing cycles to check the
    > channel for "b" traffic before transmitting every time! Instead, "b"
    > clients are simply rejected, and only "g" clients accepted, and because its
    > ONLY "g" clients, the router is much more efficient. Most routers level
    > this feature disable by default, for maximum compatibility. But if you ONLY
    > have "g" clients, it should be ENABLED for maximum performance.

    I don't think I can agree that it's *much* more efficient. The shorter
    slot time does improve throughput, but your *maximum* gain is
    theoretically about 33%. While this is significant, it certainly
    doesn't explain why his "g" adapter is *slower* than his "b" adapter
    was. Also, if you look at past threads, maximum Tivo throughput is
    nowhere near what 802.11g can support, but is instead throttled by
    internal processes in the DVR (most likely encryption duties).

    > Secondarly,
    > it's a respectable security measure, one less class of clients that can
    > appropriate your wireless system!

    Calling it a *respectable* security measure is a stretch. Since most
    new devices use 802.11g I'd say it's pretty much a *marginal* security
    measure, i.e. it doesn't hurt, but it doesn't do much good either.

    <snip>

    My views on this would be buy "g" equipment when you buy new stuff, but
    don't spend money on upgrading existing equipment if it works fine now.
    Mixed mode networks have some penalty involved but it isn't likely
    something that will impact you greatly.

    The *real* speed gains on Tivo DVR transfers are gained by hacking the
    box and removing the encryption processes totally. Others here can tell
    you more about that, but it's not nearly as simple as upgrading a
    wireless adapter.

    Also, "g" won't be the fastest wireless protocol on the block for very
    much longer. 802.11n (touted mostly as "MIMO" right now) has not been
    ratified yet, but pre-ratification products are already coming out.
    These devices are basically very similar to 802.11g (and are backward
    compatible, fortunately) but use multiple receivers and multiple
    transmitters in order to increase range and reduce deadspots. They
    reportedly work very well, I'd definitely recommend getting them when
    they become widely available.

    Randy S.
  3. Archived from groups: alt.video.ptv.tivo (More info?)

    Sorry, I was at work and just saw the replies, which i greatly
    appreciate. Jim, I have the DI-624 same as you and I found the option
    to trun on "g" only and I see what you mean about that. Like I said in
    my origianl post witht he d-link "b" adapter iwas using I think it was
    about 1 1/2 hours to transfer a 1 hour show. does this sound right?
    with the new dwl-g120 adapter it says that it is goignto take 3 hours.
    My big questionwas that on the TiVo website they said the dwl-g120
    version B2 was compatible. after i got it home i saw on the box that it
    was a B1. It looks the same as the B2. does the hardware version make
    that much difference to where the speed would be that much slower? all
    I did when I connected it to my TiVo was plug it in the USB port and
    then the Tivo restarted itself. Should I have done something different?
    Is there a way to tell which device the Tivo thinks is conneceted so i
    can make sure it is using the right driver?

    Thanks for all the replies I greatly appreciate it. Steve.


    Randy S. wrote:

    > Comments interspersed, please see
    > http://www.proxim.com/learn/library/whitepapers/parameters_802.11g_performance.pdf
    > for one source of documentation:
    >
    > Jim wrote:
    >
    >> I can't be 100% positive here, but I can conjecture a pretty good guess.
    >
    >
    > Well, your guesses have some bearing with reality, but fall short of the
    > mark in several aspects.
    >
    >> Presumably your current wireless network supports "b" and "g". Most
    >> consumer model routers from Netgear, Linksys, and D-Link (esp.
    >> D-link), do
    >> NOT perform as efficiently when running in mixed mode, i.e., support
    >> 'b" and
    >> "g" clients concurrently.
    >
    >
    > This is true, though I want to point out (and will back up further down)
    > that you are overstating the effects.
    >
    >> Although supported, it's with caveats (that the
    >> vendor usually doesn't make much mention of, for obvious reasons).
    >
    >
    > Mostly because the issue is much too complex to the casual user, and
    > doesn't really matter that much to them.
    >
    >> First,
    >> when running both "b" and "g" clients concurrently, most routers will
    >> DOWNGRADE the "g" clients to "b" performance, simply because it can't
    >> actually do two things at once, it's either "b" or "g", and if a "b"
    >> client
    >> is transmitting when a "g" client also wants to transmit, rather than
    >> wait
    >> for all "b" transmissions to cease, the router simply forces the "g"
    >> client
    >> to run in "b" mode (or else does make it wait).
    >
    >
    > This is sort-of true. It *is* true that only 1 device on a given 802.11
    > collision domain can broadcast at once, so that when your "g" device is
    > broadcasting, your "b" device must wait. But this happens even if you
    > have all "b" devices or all "g" devices. What is *not* true is that
    > your "g" devices are forced to transmit in "b" mode. The only change
    > that your "g" device has to do is use a longer "slot" time (20
    > microseconds vs. 9 microseconds) to be compatible w/ the "b" device slot
    > times. This has an effect, but it's probably about a 20% penalty, not
    > the 80% penalty that would be incurred from going from 54 Mbps to 11 Mbps.
    >
    > The one situation where you *may* see such a high penalty is where you
    > have *2* overlapping mixed wireless collision domains (i.e. 2 wireless
    > routers) on overlapping or identical channels, but this is not the
    > typical residential wireless scenario, it's more of a problem for
    > corporate networks.
    >
    >> Second, in order to improve
    >> the situation, the typical "g" router (a good one anyway, like my D-Link
    >> DI-624) supports something called "802.11g Only Mode". It may go
    >> under some
    >> other name w/ other products, but if it's there, its under the wireless
    >> configuration section (e.g., w/ Belkin F5D7230-4 and F5D7231-4
    >> routers, it's
    >> called "54-G Only"). Why does this exist? Because when you enable this
    >> feature, the router doesn't have to waste processing cycles to check the
    >> channel for "b" traffic before transmitting every time! Instead, "b"
    >> clients are simply rejected, and only "g" clients accepted, and
    >> because its
    >> ONLY "g" clients, the router is much more efficient. Most routers level
    >> this feature disable by default, for maximum compatibility. But if
    >> you ONLY
    >> have "g" clients, it should be ENABLED for maximum performance.
    >
    >
    > I don't think I can agree that it's *much* more efficient. The shorter
    > slot time does improve throughput, but your *maximum* gain is
    > theoretically about 33%. While this is significant, it certainly
    > doesn't explain why his "g" adapter is *slower* than his "b" adapter
    > was. Also, if you look at past threads, maximum Tivo throughput is
    > nowhere near what 802.11g can support, but is instead throttled by
    > internal processes in the DVR (most likely encryption duties).
    >
    >> Secondarly,
    >> it's a respectable security measure, one less class of clients that can
    >> appropriate your wireless system!
    >
    >
    > Calling it a *respectable* security measure is a stretch. Since most
    > new devices use 802.11g I'd say it's pretty much a *marginal* security
    > measure, i.e. it doesn't hurt, but it doesn't do much good either.
    >
    > <snip>
    >
    > My views on this would be buy "g" equipment when you buy new stuff, but
    > don't spend money on upgrading existing equipment if it works fine now.
    > Mixed mode networks have some penalty involved but it isn't likely
    > something that will impact you greatly.
    >
    > The *real* speed gains on Tivo DVR transfers are gained by hacking the
    > box and removing the encryption processes totally. Others here can tell
    > you more about that, but it's not nearly as simple as upgrading a
    > wireless adapter.
    >
    > Also, "g" won't be the fastest wireless protocol on the block for very
    > much longer. 802.11n (touted mostly as "MIMO" right now) has not been
    > ratified yet, but pre-ratification products are already coming out.
    > These devices are basically very similar to 802.11g (and are backward
    > compatible, fortunately) but use multiple receivers and multiple
    > transmitters in order to increase range and reduce deadspots. They
    > reportedly work very well, I'd definitely recommend getting them when
    > they become widely available.
    >
    > Randy S.
  4. Archived from groups: alt.video.ptv.tivo (More info?)

    Steve Ball wrote:
    > Sorry, I was at work and just saw the replies, which i greatly
    > appreciate. Jim, I have the DI-624 same as you and I found the option
    > to trun on "g" only and I see what you mean about that. Like I said in
    > my origianl post witht he d-link "b" adapter iwas using I think it was
    > about 1 1/2 hours to transfer a 1 hour show. does this sound right?
    > with the new dwl-g120 adapter it says that it is goignto take 3 hours.
    > My big questionwas that on the TiVo website they said the dwl-g120
    > version B2 was compatible. after i got it home i saw on the box that it
    > was a B1. It looks the same as the B2. does the hardware version make
    > that much difference to where the speed would be that much slower?

    Somewhat unlikely, but certainly possible.

    > all
    > I did when I connected it to my TiVo was plug it in the USB port and
    > then the Tivo restarted itself. Should I have done something different?
    > Is there a way to tell which device the Tivo thinks is conneceted so i
    > can make sure it is using the right driver?

    When adding a USB wireless adapter to your Tivo, always restart it
    afterwards. I don't think Linux is quite as plug and play (or plug and
    pray ;-) ) as Windows is.

    But I would guess you may be running into interference issues. Try
    setting your router to use a different channel. If it's on 1, try 11.
    If it's at 11 try 1. If it's at 6 try either 1 or 11. The rest of the
    channels overlap, so 1, 6, and 11 are probably the best ones to try.

    Randy S.
  5. Archived from groups: alt.video.ptv.tivo (More info?)

    D-link is awful in respect to their internals.
    They will keep the same product model number, but change the understand in
    the process make them not compatible with previous drivers.
    The B1 and B2 are very different.

    If you go to their web site and try to download drivers for it. the driver
    version is different for each Sub-release.

    This problem spans their product line.

    --
    Steven BerkHolz
    Send to Domain TESCOGroup dot com, username SB

    Note: you may also want to know that you should never send mail to:
    blacklist-my-ip@admins.ws
    info@dautrap.uceprotect.net
    listme@sorbs.net
    spamtrap@sandes.dk
    spamtrap@stop.mail-abuse.org
    spamtrap@frankenbiker.de
    spamtrap@blars.org
    "Steve Ball" <groucho111@sbcglobal.net> wrote in message
    news:VCc5e.20075$DW.6946@newssvr17.news.prodigy.com...
    >I had a d-link dwl-122 "b" adapter connected to my TiVo and it was slow but
    >it worked. OfficeDepot had a D-link dwl-g120 "g" adapter on sale for $20
    >after rebates so i bought one of them yesterday. It seems like it
    >transfers slower than the "b" adpater that I had connected. I lookeda the
    >box after i tried it and saw that it is version B1 and the Tivo website
    >says that it should be version B2. would it cause that much of a
    >difference between the versions? should I retrun the b1 and try to get a
    >b2. My other thought was to get one of the netgear wg111's but on the
    >internet it seems that there are several versions with letters after the
    >adapter. not sure which is the right one to use. any advise would be
    >appreciated.
    >
    > thanks, Steve
  6. Archived from groups: alt.video.ptv.tivo (More info?)

    Thanks for all the repiles. I think I am going to retuontrn the
    dwl-g120 and just stay with the "b" adapter i have right now. To verify
    what i was saying i tried to move a 1 hour show with the dwl-g120
    attached and tivo desktop said it was going to take over 3 hours to
    transfer the show. I disconnected the dwl-g120 and reconnected the
    dwl-122 i had before and tried it again. With the "b" adapter connected
    it said it was only going to take a little under 2 hours to transfer the
    same show. I tried all the things i could such as setting my router for
    "g" only and it didnt make a difference. the only thing i can think of
    is the version of the card being 1 off from what tivo says is supported.
    oh well. maybe they'll add some drivers later for faster devices that
    wll actually work.

    thanks for all the help.

    Steve

    BerkHolz, Steven wrote:
    > D-link is awful in respect to their internals.
    > They will keep the same product model number, but change the understand in
    > the process make them not compatible with previous drivers.
    > The B1 and B2 are very different.
    >
    > If you go to their web site and try to download drivers for it. the driver
    > version is different for each Sub-release.
    >
    > This problem spans their product line.
    >
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