Wireless Access

Hello my name is Tobi,

I´m new in wireless and I´ve some questions.

How can I get (what must I configure) to get 450 Mbit´s from an AP125?

Now I get an MCS Index of 15 (2 Streams, 300 Mbit´s) but I think the AP125 can make 3 Strams and 450 Mbit´s!? What must I configure?

How does the AP125 scale this 3 Steams or is it only possible to get 2 strams of 5 Ghz and 1 of 2,4 Ghz?

Is one Antenna for 2,4 Ghz and 2 for 5 Ghz?

Thank you.

Tobi

The AP-125 is a 2x2:2 AP (2 spatial streams) and can go up to 300Mbit.

The AP-13x series (134 and 135) are 3x3:3 (3 stream) and can go up to 450Mbit.

OK.

Thank you!

How can I configure it on a AP 135 there is the same problem I only get 2 streams on the AP135, too?

Does your device support 3x3x3?

yes I think so. I have this wlan adapter:

Maybe I must tell you something about my lap:

I´ve a 651 Controller and at the moment a AP125 and a AP135 on the run.

Can you post the output of

show ap ht-rates bssid <bssid>

Ok I must check this on monday.

Maybe I´m only connect to the AP125.

I must check this on monday and I write the result.

Hi

As a general recommendation, I would recommend using different AP groups for the different models you have. By doing so you can test this kind of features easily.

regards

OK Thank you @ all.

Now I get 450 Mbps from the AP135 and 300 Mbps from the AP125! :smileyhappy:

Ok noch I checkt it out.

When I connect to the AP135 it shows 450Mbps but I don´t get this rate!

That´s not bad but that´s not 450 Mbps.

How can I get the maximus rate of my AP135?

What must I configure to get this?

Thank you!

tobiasg,

450 is only the negotiated rate.  There is quite a bit of overhead in wireless so you will never see more than half of that.

OK, but 16,6 is not the half its to small.

When I´m the only one who is connect to this AP135 I must get a better rate isn´t it?

Can I configure anything to tune the rate up?

Thanks

There are quite a few things you can do:

Make sure power save is off on your client.

Make sure no other devices/clients are on the same channel.

Make sure that there is an obstacle between your laptop and the access point so that you can leverage multipath

If you are using iPerf to measure throughput, make sure you use a Window Size of at least 512K

Make sure that you have "Drop Broadcast and Multicast" enabled on your Virtual AP.

Sometimes the limitation is how fast each device has access to the disk subsystem.

How the WLAN driver aggregates and de-aggregates the packets can drop the throughput.

A file copy is not optimized for wireless throughput, so you can only get so much performance while copying.

Long story short, nobody ever achieves speeds of 450Mbits/sec or even half of that.  The ones that achieve that do it in the lab, with no interference and with client Window sizes tuned up to 512K on both sides, and most clients are not tuned that way, so that is probably unattainable in the real world.

Ok thanks,

It´s only for testing I want to get the best rate.

Have anybody a realistic benchmark or thoughput tests from an AP 125 and AP 135?

I´m so interestet what is the maximum thoughput of these APs.

here is a sceenshot from the controller:

I think there must go more throughput!?

Goodput is the "real" traffic minus the overhead.  The dashboard information is collected at intervals, so it does not show second-by-second throughput.  You should use iperf for Windows or Linux to obtain that.  Use the switches below:

Client Side:

iperf -c <ip address of iperf server> -w 512K -t 100 -i 10 -r -P 4

Server Side:

iperf -s -i 10 -W 512K

Ok this is what iperf shows:

I think this is the maximum I can get from my AP135.

This is a iperf screenshot.

But I don´t realy understand why in the product paper 450 Mbps stands?

There are many factors that control that.  450 is only the link speed, NOT the real throughput.  You will never get anything close to that.  You need to have:

- The access point on a gigabit connection

- the controller on a gigabit connection

- everything in the path on a gigabit connection

- Drop Broadcasts enabled on the Virtual AP

- No other wired or wireless devices on that VLAN

- No other devices on that channel

- No interference on that channel

- Turn off power save on your client

It is like plugging into a gigabit ethernet port and not getting gigabit throughput.  Wireless is a shared mechanism so it will not get anywhere near that.  You could get 200+ in a lab maximum under perfect circumstances.