Disconnecting while on Wireless Network

[vishal.rane]

Hi

Some users raised issue for disconnection while accessing network via wireless. AP model - AIR-AP1131AG-E-K9. Cable connecting to AP is likely not an issue. what should be checked on the wireless lan controller to identify the issue

any comments will be appreciated

Thanks in advance

Vishal

[Leo Laohoo]

Id first be checking the signal strength.

Next, I would be looking for signal interference.

What protocol do disconnection occur? 802.11b?

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[Scott Fella]

You need to tell more info. I'm guessing this is a standalone AP? How many and what are they saying when about when they disconnect? What did you do to troubleshoot the issue so far? Is the issue reproducible? What does the logs show and what authentication method are you using.

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[vishal.rane]

Thanks both for input

AP is joined to controller not standalone.

Total of 15 users connect to the AP but around 6 to 8 complaint disconnection and even when there are 5 users still some complaint disconnection.

1. I checked the cable
2. ping to the AP with no timeout
3. restarted the AP
4. Authentication is  [WPA + WPA2][Auth(802.1X)]     &&  [WPA2][Auth(PSK) users on both these SSID complaint
5. Signal Strengh is good not too far from the AP

Looking at time statistics for AP

[vishal.rane]

Hi leo

how to check interference from the controller, can the WLC select the best channel to avoid interference.

How to enable log on WLC for specific AP

thanks

Vishal

[Leo Laohoo]

WAP uptime of only "7 hours"????

I'd be looking as to WHY?  If the answer is power then the question I'd be asking you is how is this WAP being powered?

[vishal.rane]

Hi leo

I mentioned in the post I restarted the AP, maybe not clear.

The AP is sourced power with power injector.

How do i check interference and sort this out if issue noticed

thanks

Vishal

[Leo Laohoo]

Ok, so if it's controller-based then I'd be looking if Dynamic Channel Assignment (DCA) and Tx Power Assignment is on by default.

Next look at each client to see what signal strength the AP can see the clients.

Is this issue happening to everyone of just a few clients?  Or specific clients?

[vishal.rane]

Dynamic Channel Assignment Algorithm

Automatic

Tx Power Level Assignment Algorithm

On Demand

on couple of clients i noticed the signal strength is same and good

it happens to everyone not specific ones

[Leo Laohoo]

on couple of clients i noticed the signal strength is same and good

Define "same and good"??  3/5?  4/5?  5/5?   This is only the signal strength from the client to the WAP?  What about the signal strength from the WAP to the client?  Go to the main page of the WLC and click on "Clients" link on the left-hand corner.  Click on the MAC address of the client that are reporting to have problems and look under RSSI.  What are their values.

When you mean by "disconnection" does this mean the clients get disconnected on ALL applications (such as email, web, etc) or just a particular application (email and/or web are OK but they can't access shared directories or payroll applications).

[vishal.rane]

Leo thank you for replying. Here is the RSSI information for users getting issue.

Issue happens when accessing email , sharepoint portal , oracle , SQL

Rating is 4/5 and 5/5

two guyz get 3/5 but keeps changing during the time ( RSSI  - 72 or  - 70 )

[Leo Laohoo]

Thanks for the response.

Wireless signal strength has to be two ways:  WAP to client and client to WAP.  In both cases, they look really good.  I mean -54 and -66 is pretty good.  -72 is, in my book, good.

Next, I am looking at the applications that have disconnections.  So when the clients say they get disconnected, they aren't disconnected from the network.  They are disconnected from the servers.  Am I right?

I mean the easiest way for them to test and "believe" that they got disconnected from the servers and not the network is when they have lost contact with the server can they still surf the net.  If they can then focus can now shift to investigating the problem there.

Just out of curiousity "accessing email , sharepoint portal , oracle , SQL", are these all housed in a physical server or a cluster or a blade chassis?

[vishal.rane]

Thanks Leo

we connected 2 trouble users machine with wired network connection and no issue reported. Others still reported issues, we started pinging continiously to Gateway from them and let them work as well - again noticed that wireless connection goes off and comes back again within seconds. ping to gateway is lost as well during disconnection of wireless.

All application is hosted locally when ping normally it gives result on wireless

Pinging 192.168.1.254 with 32 bytes of data:

Reply from 192.168.1.254: bytes=32 time=3ms TTL=64

Reply from 192.168.1.254: bytes=32 time=4ms TTL=64

Reply from 192.168.1.254: bytes=32 time=3ms TTL=64

Reply from 192.168.1.254: bytes=32 time=3ms TTL=64

Ping statistics for 192.168.1.254:

    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

Approximate round trip times in milli-seconds:

    Minimum = 3ms, Maximum = 4ms, Average = 3ms

[Leo Laohoo · Accepted solution]

we connected 2 trouble users machine with wired network connection and no issue reported.

Yes.  I've seen server issues/misconfiguration where wired connection works (very well) but wireless won't work.

Others still reported issues, we started pinging continiously to Gateway from them and let them work as well - again noticed that wireless connection goes off and comes back again within seconds.

Do a continuous ping "-t" and with 1500 size packets.

ping to gateway is lost as well during disconnection of wireless.

Use different clients and not just the ones with issues.  If the clients have different wireless NICs then good.  If they are the same, even better.

You've posted the output of the RSSI level but didn't mention anything about which band/protocol was used.  If these were 802.11b/g can I ask if you force the clients to negotiate to 802.11a/n if necessary?

Can I also ask if you can Wireshark the transaction and see if there are any indication of server issues?  Look at the event logs on the servers for issue.

Check every hop from the WAP down to the server(s).  See if you see any discrepancies:  speed/duplex mismatch, CRC errors, interface disconnections, output drops, reliability/Tx/Rx drops, etc. 

[vishal.rane]

Hi Leo

How to force the clients to negotiate to 802.11a/n only

thanks

Vishal