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samsoft08
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Max clients on single radio RB with WDS..

Sat Feb 24, 2007 9:52 pm

I read somewhere here that the theoritical MAX clients on a single radio RB532 ia about 50 user ..

what if i made a WDS with 3 RB532 , the first one is connected to the main MT-PC , the other 2 RB's are connected to each other and to the first RB ..

can I put more than 50 user on the whole network ?
is it possible for example to put 50 on the 2nd RB and 50 on the 3rd RB?

note : the link between the RB's made by another radio 5G..
 
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marksx
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Sun Feb 25, 2007 9:56 pm

clients on 5GHz ?
yes, but only on other MT's with nstreme with polling enabled

If you are planning to use classic windows machines with 5GHz card installed, you can't reach more than 1200meters and more than 10-15clients - even with strong signal.

Let assume that we will have

RB532 Base station with Atheros card with 16dBi sector antenna

100 Clients with RB 133C with atheros card with 18dBi antenna

you probably can reach stable 2-3km distance ( assuming low noise area, and good wireless instalation with clear LOS ) and performance should be about 10Mbps full duplex (excluding intrabss traffic) agregate on whole wireless interface
so 10Mbps / 100 = 100Kbits
we can assume that not all clients will consume their bandwidth, but only 20%, so that can allow us to sell them ~512Kbits
if that's ok to you - there shouldn't be any problem

Here in Poland, some WISP's have running 5GHz bases with 30 CPE to one base station antenna, but with 1 or 2Mbps bandwidth option for client,.
 
babyface
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Mon Feb 26, 2007 6:36 pm

One questions... is better WDS than AP-Client with multiple stations scenarios??
 
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marksx
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Mon Feb 26, 2007 6:53 pm

the only difference between routing (clasic AP-bridge - station structure) and wds-bridge, are 6 addional bytes in header of wireless packet, related to mac addresess behind the station-wds site.
So there's no really difference in performance (just 6 bytes per packet), but in bigger network, there's problem with packet colisions and with broadcast ( add to this Vulnerabilities to arp attacks) , so i'd preffer routed network over bridged one.
 
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samsoft08
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Mon Feb 26, 2007 11:57 pm

5G for the link between RB nodes ..
2.4G for clients ..
its a WDS setup consists of 3 RB nodes linked to each other , and one of them is connected with the main MT-PC by wire ..
all of the 3 RB's are connected to regular clients (2.4G) with d-link , senao ... etc ..
so my question if the single RB max clients is 50 , what about the one which is connected to the main MT-PC ? assuming that there are 50 user connected to it , and the other 50 user for each 2 RB's ..??
 
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marksx
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Tue Feb 27, 2007 3:13 am

there's no such limit on RB's
you can connect even more but:

maximum (with still some quality level) performance of single 802.11b radio is about 2500Kbits (assuming normal outdoor conditions and medium noise levels), but thats only in one direction - so you can have 1500/1000 or 2000/500 etc
but maximum the packet per second rate defined by time slots in 802.11b standard is on 500pps level in one direction (like before, normal outdoor conditions) and pps are typicaly symetrical with download only little higher like 250/220 and 250/250 in most cases (if you have more on recive that's probably DoS attac pron your wireless clients ... )

So try to measure avarege pps rate of typical service you would like to sell.
Me for example with torrent active session on 1Mbits download and 500Kbits upload level, get about 135/115pps (250 ageregate) average ratio.

So you could connect clients like me only... two guys at the same time ...

normal client only web surfing - without _any_ download
is about 30/30 pps typicaly (when oppening websites)

one voip session is rated on 50/50 pps level, with special codecs you can get 30/30 pps but the quality will probably decarase.

so if you want to sell cheap internet without any quality you can connect 50 clients to one radio and that will probably work.



the other solution is :

use sectorized antennas (if you want to buy some give me an info) instead omni ones and use two or there wireless 2,4GHz cards with one 5GHz uplink on one base station
you really shouldn't put more than 3 antennas on 2,4GHz freq on one mast (because of interferences)

So let assume that we wil have 3 antennas:
the performance is almost 3 times greather than on one card
the pps radio on whole base station ageregate can be even 1500 pps (that about 50 active web surfers, 20 voip calls at the same time or 6 to 10 torrent guys)
basicly not every client is connected at the same time so you can connect 40-50 users on this whole bs and no one should complain regarding to performance, you can connect even more like 50-70 but you'll need to drop something and probably forget about VoIP

but that's ok i think, regarding typical range of normal base units on 5km level, if you can connect more, that means you shold bulid another BS near clients you want to connect - the basic law of cell network...

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