Abnormal latency on APs

RouterOS Wireless Networking
1

AP:
MK112 with prism 2,5 card. 12 connectred clients. And latency si around 2-6 ms. It is very cool but not for long time. A rest of time the latency is around 150 - 400 ms.

If latency is 2-6 ms the throughput could be higher with no roblem. 1200 / 500 kbps

If latency is high the throughput coldn`t be higher than 300-400 kbps.
Defauld forward is disabled, broadcast is filtered with netbios, too.The connections are limited for 150 / user!

And the are a lot of droped packets!I tryed to change the frequency too. It is the same.

I tryed change ROS version. I tryed beta v. too. It is the same!

This problem is not only on thi one AP. I thought:the problem is witch cm9 wlan card.I changed it for Prism 2.5. It is the same.

Please help!!!

2

LAN and Wlan interfaces are bridged!

3

The RB112 can’t fully utilize your radios (especially not PRISM cards!). You need RB5xx do this kind of setup.

4

On the 2 lines I have RB 532 with the same configuration. And the problem is the same!

5

On the 2 lines I have RB 532 with the same configuration. And the problem is the same!

6

Where are you seeing packet drops? How do you measure it?
What’s you configuration?

7

Where are you seeing packet drops ?

Some pings are droped if i`am trying ping connected client on AP! around 20 %

With ping command on the command line

What’s you configuration?

What kind of configuration you mean? I use 2.4 GHz B

8

What’s the load at the time? What’s the response time? Exactly what kind of client are you pinging? What is the AP wireless configuration?

9

cpu load is around 20 %

ping for ethernet interface is all right!

the clients are ovislink 1120,5450,5460



 name=" XXXXXXXX " mtu=1500 mac-address=00:02:6F:xx:xx:xx arp=enabled 
      disable-running-check=no interface-type=Prism prism-cardtype=100mW 
      radio-name="XXXXXXXX" mode=ap-bridge ssid="XXXXXXXX" area="" 
      frequency-mode=manual-txpower country=rusia antenna-gain=0 
      frequency=2427 band=2.4ghz-b scan-list=default rate-set=default 
      supported-rates-b=1Mbps,2Mbps basic-rates-b=1Mbps,2Mbps 
      max-station-count=2007 tx-power-mode=default 
      periodic-calibration=enabled periodic-calibration-interval=60 
      dfs-mode=none antenna-mode=ant-a wds-mode=disabled 
      wds-default-bridge=none wds-default-cost=100 wds-cost-range=50-150 
      wds-ignore-ssid=no update-stats-interval=disabled 
      default-authentication=yes default-forwarding=no default-ap-tx-limit=0 
      default-client-tx-limit=0 hide-ssid=no security-profile=default 
      disconnect-timeout=3s on-fail-retry-time=300ms compression=no 
      allow-sharedkey=no
10

You can get some helpful information by doubleclcking on an entry in the wireless/registration table and looking at the Statistics tab regarding what is happening below layer 3.

Pay close attention to Tx/Rx Frames vx. TX/Rx HW Frames. For a good connection, they will be identical, even if in the millions or higher.

Further, local interference in a neighborhood may mean different service levels across the coverage area of the AP (if, e.g., said AP covers multiple neighborhoods), so optimizing cell size (and thus your exposure to multiple sources of interference) can be an issue.

Solve the lower layer problems and the layer 3 starts working magically unless you are dropping the packets yourself.

regards/ldv

11

If you cycle between times of good latency and poor latency, look for the cause of the cycle.

A single cycle (a single occurrence) can be more difficult to diagnose than a repetitive cycle, but you wind up looking at the data to find out what changed (changes) at the inflection point(s) or executing a series of SWAGs.

Turn on wireless logging and look at the log file as well as the Statistics tab for particular connections under wireless/registration-table.

best regards/ldv

12

The cycle between times of good latency and poor latency is not equal.Usualy the problems with poor latency are at night.

the severance betwen Tx/Rx Frames vx. TX/Rx HW Frames are monimal. RX frames are equal. TX is little different …Very little

13

is there fog or other moisture in air at nights?

or some other hot/cold air layer anomalies?

they can cause high ping too.

14

No, the weather is fayn!

15

Were the ping times good or poor when you took that lab note?

Whether good or bad, did you make a second lab note regarding the opposite condition?

If so, what was that result?

regards/ldv

16

Sorry, I don`t understand what you said

17





  1. Please reply with lab notes regarding:

Tx/Rx Frames vs. Tx/Rx HW Frames

1a). under good conditions (good ping times)

and

1b). under poor conditions (poor ping times).

  1. Please turn on/enable wireless under Winbox/system/logging and check said syslog for interesting (i.e., not nominal) entries during times of poor conditions (poor ping times).

regards/ldv

18

The problem is card, cm9 and prism card is not good for ap. The best card for ap is orinoco, but MKT no support is.

19

What kind of orinoco? Can you write current type?

20

I heard so the best effort for AP whit MK is mini PCI card with prism 2,5 chipset.

Who can confirm it?