Slow Links

RouterOS Wireless Networking
1

Hi All,

I was woundering if anyone could help explain why i’m getting slow links.

The link is only 1mile long, i’m using a athlon 64 at one end and a p3 500. Both ends are using CM9’s and have LMR400 cable runs to 19dbi Parabolic Grid antenna.

The following is the wireless config
Station

[admin@MikroTik] > interface wireless print
Flags: X - disabled, R - running
 0  R name="wlan1" mtu=1500 mac-address=00:0B:6B:35:32:7D arp=enabled disable-running-check=no interface-type=Atheros AR5213 radio-name="000B6B35327D"
      mode=station ssid="Freedom-Cant" area="" frequency-mode=manual-txpower country=no_country_set antenna-gain=0 frequency=5800 band=5ghz-turbo
      scan-list=default rate-set=default supported-rates-b="" supported-rates-a/g=12Mbps,48Mbps basic-rates-b="" basic-rates-a/g=12Mbps,48Mbps
      max-station-count=2007 ack-timeout=30 tx-power-mode=default noise-floor-threshold=default periodic-calibration=enabled burst-time=disabled
      dfs-mode=none antenna-mode=ant-b wds-mode=disabled wds-default-bridge=none wds-ignore-ssid=no update-stats-interval=disabled
      default-authentication=yes default-forwarding=yes default-ap-tx-limit=0 default-client-tx-limit=0 hide-ssid=no security-profile=default
      disconnect-timeout=3s on-fail-retry-time=100ms preamble-mode=both compression=no

Ap

Flags: X - disabled, R - running
 0  R name="wlan1" mtu=1500 mac-address=00:0B:6B:35:B0:00 arp=enabled disable-running-check=no interface-type=Atheros AR5213 radio-name="000B6B35B000"
      mode=bridge ssid="Freedom-Cant" area="" frequency-mode=manual-txpower country=no_country_set antenna-gain=0 frequency=5800 band=5ghz-turbo
      scan-list=default rate-set=configured supported-rates-b="" supported-rates-a/g=6Mbps,9Mbps basic-rates-b="" basic-rates-a/g=6Mbps,9Mbps
      max-station-count=2007 ack-timeout=30 tx-power-mode=default noise-floor-threshold=default periodic-calibration=enabled burst-time=disabled
      dfs-mode=none antenna-mode=ant-a wds-mode=disabled wds-default-bridge=none wds-ignore-ssid=no update-stats-interval=disabled
      default-authentication=yes default-forwarding=yes default-ap-tx-limit=0 default-client-tx-limit=0 hide-ssid=no security-profile=default
      disconnect-timeout=3s on-fail-retry-time=100ms preamble-mode=both compression=yes

Now i’ve fixed the data rates and did some tests, the only thing that changes is the data rate i have fixed. The test is run via downloading a 500mb avi file from a http server connected to ethernet at the AP end. The File is downloaded to a laptop connected to ethernet on the Station side.

6mbit, 920 Kilobytes/Sec
9mbit, 1120 Kilobytes/Sec
12mbit, 1740 Kilobytes/Sec
18mbit, 1190 Kilobytes/Sec
24mbit, 1280 Kilobytes/Sec
36mbit. 1760 Kilobytes/Sec
48mbit, 1380 Kilobytes/Sec
54mbit, Wont Stay at 54mbit, Slips back to 6mbit

These tests were down 3 times in a clear day about 4 hours apart. is anyone able to tell me why i never seemt o be able to pull more than 13.75mbit(1760Kilobytes/sec) even on a stable 36mbit link with NStream enabled?

For 36mbit with Nstream i was expecting to pull atleast 2000kilobytes/sec.

I ran this test via a EOIP tunnl to bridge to 2 lans, could this be part of the problem??

Anyone would be very handy

Cheers

2

Just an update - i decided to take the EOIP tunnel out and the link is running slightly better but still less than expected.

36mbit, 2420Kilobytes/sec

Thats with compression and Nstream - still alot less than ther 4500kilobytes/sec that 36mbit should give you. Does anyone have any idea what i can do to speed up my links?

3

Ok as a beginner from playing with the MT gear… I would say shut it down for a few minutes… or reboot the heck out of it.

Now I am new to this MT stuff but from my experience I would recommend….

Have you checked all the variables?? Like cable connections… signal strength, Tx power. You may get faster speeds if you set NSteam to a dynamic frame policy… and a framer limit of something like 512 to 1024.
I would say remove compression… I personally don’t believe in using it.

Who knows why the links are going slow. From my experience MT can be fickle at times.

4

Hi,

I tried what you said, changing Nstream resulted in a 200-300kb/sec drop in speed, i even tried the reboot option, turning compression off did help about 50kb/sec

The link is stable at -70 TX and -68 RX , forced 36mbit mode and its fine - can pull Gb’s of data through it without any issue - its just not using all of the link, i expected to see 3000KB/sec+ for a stable 36mbit link with Nstream turned on