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I have an application running on Server 2008 which wireless clients connect to with a client app. I started with a Cisco WAP4410N, but the connection was unusable slow so I updated the switch to a 24-port Gigabit Netgear and added a Netgear WNDAP350 as I was unhappy with the WAP4410N. This is in a smallish area, but both the 4410N and the WNDAP350 can cover it so I gave both different SSIDs and placed them on opposite ends of the 5 GHz frequency with a 40 MHz signal. The idea being I could split the load between them, lower chances for interference, and keep throughput high.

Unfortunately running perfmon on the server shows disk I/O is spiking really hard as it total network I/O. The primary symptom is the computers hang on action with no network activity seen on the wireless networking connection on task manager > networking.

At this point I've exhausted my ideas and I'd ideally like to be able to point to a graph and say, "this here is the problem". But with several possible problems it isn't obvious to me the issue. If there is any information I've left out please let me know.

Thank you all.

(software is based on sql server express 2005)

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First determine if it's a network issue (since you mentioned heavy disk I/O with a wireless connection). Can you connect to the application OK via a wired 100 Mb connection? – USACASD Mar 23 '11 at 18:04
Yes, the wired connections seem to fair better, but I'm told and have seen they also have intermittent slow down. – Radix Mar 23 '11 at 19:34
Since I'm inclined to think a hanging wireless connection could cause the servers disk and network interface to hang I'm going to try running NetStress on one then all machines simultaneously as here: blog.sudonetworks.com/2010/05/wireless-throughput-testing.html I'll record the b/sec to the application server and compare to what I get during the day using perfmon. This seems reasonable and obvious, which means if I'm wrong I've know way to know and I'd like to be corrected. – Radix Mar 23 '11 at 19:48
Have you determined the cause and have you found a fix? – USACASD Mar 28 '11 at 21:46
Disappointingly no. I found the WNDAP350 entered promiscuous mode in the past and even with no load on the server or network it connections through it will be... paused. I wasn't able to run iperf and netstress Sunday like I'd wished as the connection was blocked with iperf and I ran into an error with Netstress where it claimed iirc the interface could only be bound once. – Radix Mar 29 '11 at 17:34
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