Problem with continuous connectivity

RouterOS General
1

Hello everyone,

I’m doing some tests with 802.11n usb-wifi adapters. I have a software that sends one package/sec and records whenever this package is not delivered (something like a ping). This software is running on 5 computers, three of them with 802.11n usb-wifi adapters (TP-Link, Multilaser and D-Link) and two of them with 802.11g usb-wifi adapters (both OIWTech). Below are the results of 3 straight-days testing:

D-Link TL-WN722N (n) 102 not delivered packages
Multilaser RE025 (n) 125 not delivered packages
TP-Link DWA-125 (n) 112 not delivered packages

OIWTech1 (g) 43 not delivered packages
OIWTech2 (g) 11 not delivered packages

It is possible to see a great difference between (g) and (n) tests. I would like to know if this may be something I can have configured wrong (and tips of where I could start looking for this mistake), or if this is something common for Mikrotik when used with 802.11n.

Additional information:

  • This test was repeated and got similar results.
  • There were no synchronicity between lost packages from different adapters.
  • The network was in regular use.
  • I’m running version 5.6 with RB411A.

Thanks for helping!

2

Can someone help me, please?

3

There can be several things wrong.

  • Did the tests on all PC’s run at the same time?
  • Where all 5 usb adapters at the same time associated?
  • Was there at times heavy (congestion?) traffic on your (wireless-)network?

If ´g´ and ´n´ devices are at the same time associated to an AP than it basically means the AP works in ´g´ mode. The ´n´mode adapters are as part of the 802.11n protocol downwards compatible. You only have a ´n´ mode network if all associated radio’s are working in ´n´ mode.

Are any other interfering 2,4Ghz electromagnetic sources around? Interference could destroy any link.
How far/close are the test units separated from each other. Move their position to see if that gives any difference.

It could even be that some brand adapters are just better than others.
Did you check on each adapter’s config? Maybe some configuration differences as well?

I’ll bet if I think hard enough more possible issues might be around…