i have 4 sector antenna... separate channels... every seems to be fine... but some of my clients (most of them) have very poor upload speeds...

look at the registration tab in wireless settings of the ap


what could be happening here? suggestions¿?

i tried these things and problem persists:
* with different channel combination for the sectors
* setting clients tx power to higher mw

discard firewall problems or internet access problems, because i ping clients from AP with big packets (1024) and more than 80% are lost.

some of the clients with 11Mbps/11Mbps Tx/Rx Rate have serious upload problems too.

sorry for my poor english

What hardware do you use at client side?

I have had this issue, clients able to download 4 Mbps TCP, but upload is only 0.35 Mbps.
This was using 48Mbps Airrate on 2.4 ghz, 5Mhz channel sizes, with 3 x 120 degrees sectors operating at 2417, 2447, 2472 MHz.

This is most likely a CSMA back-off issue, your clients are directed at you tower (ie. pointed at all 4 sector antennas), the sectors while being 90 degrees do radiate more then 90 degrees, and if you client radio 'hears' any of the sectors transmit it will backoff.

The CSMA function is very very sensitive, in lab tests it doesn't matter if signals the client is 'hearing' is -85, or -50, it will still backoff.

The disable CSMA function should solve this issue but it doesn't work very well in RouterOS, the biggest issue in my opinion is that Nstreme needs to be on to use that function, and unfortunately Nstreme is very sensitive is noisy enviroments, and that is where the disable CSMA is most needed.

You can easily test this, wait till 3am or whenever your sectors are not in use much, do the same tests with 3 of the 4 sectors off (ie. radio disabled). Post your results becuase I am afraid that this issue is alot more serious then what many people realize. A simple 802.11b,g router with moderate usage in a house near any of your towers/cpe can have a significant impact on the performance of those devices.

I have had my fingers crossed for some time to get a Nstreme version that improves the connection in noisy enviroments instead of making it worse.

Edit: The screenshot you posted didn't load for me the 1st time, and I didn't see what you were referring to. If you are talking about the association TX/RX rate being 1 Mbps, that is because in Mikrotik it backs the radio rate down if it is not needed, this is normal operation. However if you want, and your clients have the neccessary signal strength, you can go to the 'Data Rates' setting for your wireless cards, and configure the rates you use. I use this extensively with my APs, having radios continously switch Data Rates decreases overall performance.

If however you were actually referring to actual upload bandwidth (raw TCP/UDP), then my original post is still correct.

What hardware do you use at client side?

they are not MT cpe. they are edimax, d-link, micronet...

hi MyThoughts ... thanks for your answer... correct me if i'm wrong... "disable csma" only works if Nstreme is enabled... and only MT cpe can deal with Nstreme... isn't it? my clients doesn't have MT cpe.

the problem is that you need to use nstreme. That means you need MT at the clients. The radio can't work with many clients at diferent distances only if you enable nstreme.

yes i know that.
i just can't upgrade to MT all my clients ,,,, i have the problem described above and y need to solve it some way but i don't know how

I had same problems.

I had to move antennas to separate them so instead of forur sector antennas on one place I have four antennas 1KM or more away one from each other.

then I had to "relocate" my clients to different antena, so there is no crossroads in signal path .

Set all AP cards to 15 db tx power. And my problem is not gone but pretty much cant notice problems . . .

it looks like there is no simple solution for this problem

What hardware do you use at client side?

they are not MT cpe. they are edimax, d-link, micronet...

Hi,

I've solved this problem on Edimax CPE, with upgrading last edimax firmware
(v1.21) from edimax website (I don't use edimax plus firwmare).

This is my solution.

Have you finded other way to solve it ?

regards
andres.

pd: saludos compatriota ! aguante el tango, el diego, y el dulce de leche !

yes! it's incredible... i solved that problem in that way too in some clients, but i use the brazilian firmware in most of my CPE (edimax 7209) i like that firmware because i can use NAT. there must be something wrong in those brazilian firmwares. aprouter and zoneone have the same issue. i have problem also with pci wlan cards. the only one that works perfect is EW7209APg with 1.21 firmware version.

Hi, we were having the same issue, what we did was change from using 802.11b/g to only using 802.11b, which solved the issue.

We still have the clients display as 11/1 mbits, but thier link is stable, and throughput goes up to 6-7mbits.

where prior to the change throughput was down to 64kbits

Anyways hope this helps you as well

i already have all setted in 802.11b
thanks for sharing your expeience