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Recent trace - Expert info warning reporting 20% Out-Of-Order

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We have a manufacturing warehouse facility that is complaining of wireless network slowness and disconnects thru-out the facility.

I have been tasked to do a packet analysis of the problem using wireshark. I installed wireshark on a dell desktop that is inside a stainless steel manufacturing cart.

In any case, the dry mix operators use a Intermec SR61B Cordless Scanner that uses Bluetooth radio for RF communications to scan ingredients before mixing. In addition, there is a Cisco AIR-PI21AG-AK9 network interface card with an integrated dual-band 2.4/5-ghz, 1-dbi, effective-gain antenna on a two meter cable. So, the operators use the Intermec scanner to scan barcodes of packages that is connected to this dell desktop via usb using a Windows XP operating system. The clients 'scans' the barcode which sends the information over the Cisco NIC to the application server via wireless connectivity.

I am wondering if the blue tooth radio (both in the scanner gun and in the charging base) is interfering with the Cisco antenna causing interference and cause the tcp out-of-orders in my packet trace. I have read somewhere that it is recommended that the bluetooth devices should be at least 5 feet apart from other wireless devices to minimize interference. In this particular case, the Cisco antenna is about 12 inches from the Intermec base.

So, I installed wireshark on this dell pc; and I believe I am only capturing packets leaving the windows operating systems on/off the nic card. So, perhaps a real wirelss trace would be better. Nonetheless.

I will more than likely have to make another trip back to my manufacturing facility to do an spectrum analysis of interference or whatever.

Is it possible that the Bluetooth is causing interference and the Cisco antenna cannot transmit/receive packets? Thus, resulting in the expert info report of 20% out of order packets?

So my Cisco SE says: Retransmissions are common in wireless. And a certain percentage of retransmissions is acceptable. They result from several things. Multipath, interference, low SNR, hidden node, near/far, mismatched power settings, adjacent cell interference, …

Thanks so much

I will try to send a small snipet of the Wireshark Export information and a small snippet of packets. I am not sure if I am allowed to upload packet trace, but, I am open to suggestions.

asked 06 Jan '14, 08:00

kargentus's gravatar image

kargentus
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One Answer:

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answered 08 Jan '14, 09:22

Kurt%20Knochner's gravatar image

Kurt Knochner ♦
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accept rate: 15%