A few quick question for 11b vs 11g

[ninedd]

Hi,

A few quick question for 11b vs 11g:

1) If I have 50 users connected to 11b with 11Mbps rate each, would they be sharing the whole 11Mbps (11Mbps/50) or each will will get 11Mbps? This is important as we are selling wifi to students & they should be getting at least 384Kbps up/down. Simple math, only 11g rate can deliver this (54Mbps/50=1080Kbps per user)

2) Is it true that 11g is best for OFDM signal bouncing compared to 11b which is best at penetrating? Our focus is to have the signal bounced rather than penetrate the walls.

3) Is it true that 11g is more prone to inteference compared to 11b?

- When switched to 11b, I observe that it is difficult for clients to have +90% signal quality compared to 11g. Why is that happened?Hi Fariz;

1) Well, sort of - if everyone is pumping 11Mbit at the same time. In reality, no one does. That's sort of like saying "does everyone on my block (or in my City) all share the same water main?". Well, yes, they do, and if EVERYONE flushed the toilet at exactly the same time, that would be a problem. Realistically, you'll never have that happen. So, if you have 50 people on an 11Mbit connection, and you have then shaped to 384K, I'd really not expect any problems.

2) Sort of - OFDM can 'reconstruct' signal differently. CCK in 11b is a bit stronger in ways, but generally, we see better results with 11g mode.

3) Well, it's affected differently. Of course, in V3, you also have x2 and x4 which can really do wonders to help avoid interference. For us, 11g has been far better than 11b - but that's more a function of the way we can use that tool, instead of just the raw physics of the signal modulations.

- There are TONS of reasons that radios don't have 100% Qualities. Basically, the Q is a PER or Packet Error Rate, so a 50% is telling you that 1/2 of the packets aren't getting through and have to be retransmitted. That certainly can be interference that 11b is being hit by that your 11g can get around. It can also be 'SuperAG' features - we find that sometimes switching Super on and off makes a huge difference, although we are almost all WAR now, and therefor have Super on virtually everywhere.

Generally speaking, we see the best results with 11g, 2x, Short Preamble, Super On.

[tog]

Keep in mind Fariz is working with a hotspot type of setup with random wifi clients, and not with an outdoor fixed wireless AP with fixed clients of his choosing which is what your settings are best suited for.

SuperA/G off, long preamble and 11b-only is the best way to remain the most compatible with every random type of buggy wifi client that comes along on a hotspot.

Hi Fariz;

1) Well, sort of - if everyone is pumping 11Mbit at the same time. In reality, no one does. That's sort of like saying "does everyone on my block (or in my City) all share the same water main?". Well, yes, they do, and if EVERYONE flushed the toilet at exactly the same time, that would be a problem. Realistically, you'll never have that happen. So, if you have 50 people on an 11Mbit connection, and you have then shaped to 384K, I'd really not expect any problems.

2) Sort of - OFDM can 'reconstruct' signal differently. CCK in 11b is a bit stronger in ways, but generally, we see better results with 11g mode.

3) Well, it's affected differently. Of course, in V3, you also have x2 and x4 which can really do wonders to help avoid interference. For us, 11g has been far better than 11b - but that's more a function of the way we can use that tool, instead of just the raw physics of the signal modulations.

- There are TONS of reasons that radios don't have 100% Qualities. Basically, the Q is a PER or Packet Error Rate, so a 50% is telling you that 1/2 of the packets aren't getting through and have to be retransmitted. That certainly can be interference that 11b is being hit by that your 11g can get around. It can also be 'SuperAG' features - we find that sometimes switching Super on and off makes a huge difference, although we are almost all WAR now, and therefor have Super on virtually everywhere.

Generally speaking, we see the best results with 11g, 2x, Short Preamble, Super On.

[ninedd]

Oh yes, correct. I took his questions to be just 11g vs 11b in general, but yes, by all means. In a general 'hotspot' kinda deal, you'll want to keep things as standard as possible - no WEP, no Super, no Short Preamble, no Cloak, no Stealth, no Nuttin.. :)

[fariz]

OK thank you guys :) now (for the sake of evaluation) I'm running 3 APs with 3 different settings:

1) 11b + long preamble + super AG off
2) 11b/g + long preamble + super AG off
3) 11b/g + short preamble + super AG on

Will give you guys a feedback the soonest possible. :)

[David L. Vrablic]

OK thank you guys :) now (for the sake of evaluation) I'm running 3 APs with 3 different settings:

1) 11b + long preamble + super AG off
2) 11b/g + long preamble + super AG off
3) 11b/g + short preamble + super AG on

Will give you guys a feedback the soonest possible. :)

With item 1 above you also might want to try setting the speed to 11M (manual entry) and not auto when you do your testing.

Edited as suggested :
Quote "I would suggest, David, that you edit your original post to be more precise, stating clear checkbox, so any other reader would be clear from the start what you mean. Checkbox for new guys is not "new" feature, it has "always" been there, as far as they know :)."

[rbolduc]

With item 1 above you also might want to try setting the speed to 11M fixed and not auto when you do your testing.

I second that, I have some old D-link bridges I use at home for printers and they will not pass data unless I set the speed for 11 but don't check the "fixed" (so it can go slower)

My Home AP/hotspot is

802.11 B/G
Max Rate 11mb
short preamble
Super a/g on

Seems to work fine with all my friends laptops and the old bridges and even the *cough* older macs with the agere cards :)

Reed

[David L. Vrablic]

I second that, I have some old D-link bridges I use at home for printers and they will not pass data unless I set the speed for 11 but don't check the "fixed" (so it can go slower)

My Home AP/hotspot is

802.11 B/G
Max Rate 11mb
short preamble
Super a/g on

Seems to work fine with all my friends laptops and the old bridges and even the *cough* older macs with the agere cards :)

Reed

Thanks Reed for the catch.
Translation from "reversed ethnic notation."
I meant fixed as in not auto.
Not Fixed, as in locked to 11M only.

Thanks again,

[fariz]

Thanks Reed for the catch.
Translation from "reversed ethnic notation."
I meant fixed as in not auto.
Not Fixed, as in locked to 11M only.

Thanks again,

Thanks David,

Does that means any client with a speed of 5.5 & lower still be able to connect?

[DrLove73]

Thanks David,

Does that means any client with a speed of 5.5 & lower still be able to connect?

No, fixed means just 11Mbit connections, all that do not have good signal for 11Mbit connection would be disconnected.

[ripv]

No, fixed means just 11Mbit connections, all that do not have good signal for 11Mbit connection would be disconnected.

I think there are crossed wires here - as long as you don't tick the fixed box to the right of the transmit rate the rate operates as a Max rate and can step back as required. Assuming you are using 1.3.x
see here: http://forums.star-os.com/showpost.php?p=46851&postcount=1

[DrLove73]

David said:
With item 1 above you also might want to try setting the speed to 11M fixed and not auto when you do your testing.

He stated that fariz should use NOT-AUTO, but FIXED (fixed checkbox filled) rate at 11Mbit, so no 5,5 or lesser rates would be allowed (bad idea for bunch of lap-top's roaming around if you ask me).

However ripv, your statement is correct. If "fixed" checkbox is clear, entered rate is only the "max possible rate with allowed fallback". If "fixed" checkbox is checked (not empty), entered rate is only possible connection rate, and no higher or lower rates are allowed.

[rbolduc]

I meant set to max 11mb not fixed 11mb that way its more compatible to all users, I don't know a reason you would use a "fixed" rate too much chance for an error with signal and such causing disconnects..

Reed

[David L. Vrablic]

Wheww This is getting confusing.
We all know we do not want to lock the rate when dealing with potential weak or fading signals.

Dr Love, your translator failed to pick up on the difference between fixed as in designated speed manually entered, not auto---- and the Star-Os term fixed as in the fixed box checked and locked to a single rate.

Maybe the fixed should be changed to locked?

I thought I cleared the confusion up when Reed pointed out that I had posted in a manner that could be misunderstood and indeed it was.
Until that check box showed up in the menu selections the term fixed used to mean a manual entry that was not automatically determined by the software.
---------------
Fariz, As long as you don't lock the setting it should step back to 5.5 and then 2 until there is nothing for it to work with and then just go away bye bye!

[DrLove73]

Dr Love, your translator failed to pick up on the difference between fixed as in designated speed manually entered, not auto---- and the Star-Os term fixed as in the fixed box checked and locked to a single rate.

Maybe the fixed should be changed to locked?
Clear as mud right?That had nothing to do with the translator, I can understand it perfectly, I am known to even think in english sometimes, translator kicks in only with writing and forming my own sentences since in my native language we have ideal "one letter per sound" rule. So that was not an issue here.

Until that check box showed up in the menu selections the term fixed used to mean a manual entry that was not automatically determined by the software.This is an culprit. I understood you in 1.3.x terms, after the checkbox, rather than in earlier terms. I would suggest, David, that you edit your original post to be more precise, stating clear checkbox, so any other reader would be clear from the start what you mean. Checkbox for new guys is not "new" feature, it has "always" been there, as far as they know :).

[fariz]

OK thank you guys :) now (for the sake of evaluation) I'm running 3 APs with 3 different settings:

1) 11b + long preamble + super AG off
2) 11b/g + long preamble + super AG off
3) 11b/g + short preamble + super AG on

Will give you guys a feedback the soonest possible. :)


OK guys, here comes the feedback http://forums.star-os.com/showthread.php?p=56435#post56435