Hi, I’ve got a question.
Let’s say, I have a wi-fi network.
Now, I’m using 802.11g.
Question is:
When users are connecting, their speeds like 54/54, 24/18, 6/6 etc…
Now, that 54/54 mbps connected person, can push 54 mbps from a server? Or it can just push 6 mbps because of there’s a person who has 6/6 mbps connection.
Most likely based on the individual connection. Someone that has 54/54 can in theory push 54 regardless of who else is connected. That is how I understand it.
If the 6/6 person is moving data, they’ll take up more air time and slow down everyone else. If they’re not, they won’t really affect the system.
So, instead of doing 54/54 mbps connection, 6/6 to every customer is more reasonable…
No. What I’m saying is the 54mb customer takes about 1 second to download 28mbit. The 6mb customer takes about 4.5 seconds to download the same data, and the system will slow down during that time period.
Assuming you have the bandwidth to support them, the 6mb customers will cause the 54mb customers to slow down. I’m not saying to not connect someone at 6mb, but its something you need to know. Everyone is using shared bandwidth. If Bob can download 1mbyte in two seconds and Jerry will take 10, this is something you will need to work around while running your network.
Still confused. Let’s give 3 examples so you’ll tell me which one is gonna be happen:
First example:
There’s a two customers whose names are John and Jackson.
John is very close to our transmitter but Jackson connects from very very long distance.
John is available to use every wi-fi connection speed. but Jackson is only 6/6.
We have 30 Mbps full duplex internet backbone connection.
When Jackson starts to download he can max. pull 6 Mbps
At the same time John starts downloading and he can pull 21 Mbps
They aren’t affecting each other’s connection, at that time total wireless throughput will be 27 Mbps(theorical 54 Mbps)
Second example:
There’s a two customers whose names are John and Jackson.
John is very close to our transmitter but Jackson connects from very very long distance.
John is available to use every wi-fi connection speed. but Jackson is only 6/6.
We have 30 Mbps full duplex internet backbone connection.
When Jackson starts to download he can max. pull 6 Mbps
At the same time John starts downloading and because of Jackson he can pull only 6 Mbps.
Jackson causes every person to get max. 6 mbps at that time total wi-fi thoughput will be 12 Mbps.(theorical 24 Mbps)
Third example:
There’s a two customers whose names are John and Jackson.
John is very close to our transmitter but Jackson connects from very very long distance.
John is available to use every wi-fi connection speed. but Jackson is only 6/6.
We have 30 Mbps full duplex internet backbone connection.
When Jackson starts to download he can max. pull 6 Mbps
At the same time John starts downloading and because of Jackson he can pull only 3 Mbps. That effects Jackson’s connection and he’s download speeed decreasing to 3 Mbps
Jackson causes AP’s throughput to max. 6 mbps at that time total wi-fi thoughput will be 6 Mbps.(theorical 12 Mbps)
Due to the nature of the 802.11 protocol only whenever client stops asking for data, that time transmission ends.
Bottom line, lets say you actually get 3mb to Jackson, actually get 20 to John. When Jackson is communicating with the AP, John’s performance will be impacted pretty signifigantly.
And if Jackson really has a lousy connection, (which is the clear implication if he can only connect at 6/6,) then you are liable to get so many retransmits that your entire access point perfomance will be horrible and all your customers will be furious.
We don’t install a customer that can’t comfortably achieve 24/24. Ever.
George
I agree, though I stick with 18/18 as a minimum. 24 is my target.
The only solution to this problem I’ve found is to limit bad connected
customer’s even more than they are limited by their connection.
So giving a 6/6 customer 3/3 he can only block half of the airtime
of his segment. I limit the available tx-speeds and retries to save
airtime.
I would like to see a mechanism which does this automatically
and dynamicaly. As it is a time consuming job to tune Segments
manualy and it’s never optimal.
Stefan