[Soekris] PCMCIA + MiniPCI cards in net 4511
jim at netgate.com
Wed Sep 22 22:40:51 UTC 2004
Christopher R. Hertel wrote:
> On Wed, Sep 22, 2004 at 05:47:15PM -0400, Henry Spencer wrote:
>>On Wed, 22 Sep 2004, Christopher R. Hertel wrote:
>>>I work at a big University. We still have a pile of those old Orinoco
>>>AP-1000's in production. They've got two PCMCIA slots right next to one
>>>another for two radios. We use them in large lecture halls to get extra
>>Oh, I don't say it *can't* work, just that the odds are against it. And
>>the more ambitious you get -- distance, 802.11 type, etc. -- the worse the
>>odds get. Don't lose the radio cards that work; others might not.
> Our hope had been that we would see more 802.11b/g/a combo radios in
> laptops and palmtops. Then we'd install 802.11a radios scattered about in
> large lecture halls (we have some that seat 1000). The annoyance then
> would be forcing load balancing, but hey...
Palmtops, probably not.
Laptops: Intel now produces an 802.11a/b/g Centrino.
> The practical problem is that there simply isn't enough bandwidth
> available if 1000 people are all trying to run 802.11 in a single space.
> We ran into this the last time the IETF held a meeting in Minneapolis (a
> quaint suburb of St. Paul).
Yeah, 802.11 doesn't scale quite that well. Most APs would limit
associations way before 1,000. The protocol runs out of AID space at
2008 (the max size of a TIM).
But the contention-based aspect of the protocol will fail long before
you reach that level.
There have been a number of theoretic and emperical studies of the
problem. Asking Google for "802.11 throughput" will get you some of
them. Here is one example:
> When the APs were cranked down low enough to
> force localized cells in the room, the W/XP and MacOSX clients would
> automagically switch into ad-hoc mode and everyone around them would
> be sucked in.
Thats an implementation issue (not a protocol issue).
I can't help it that Microsoft and Apple made the world worse.
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