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Thread: Capture of an OR suite

  1. #1

    Default Capture of an OR suite

    Hi all. I'm pretty new to wireless, but not to networking. I work in a hospital and here is my situation.

    We expanded our wireless in the hospital due to the addition of wireless medcarts and laptop carts. We run multiple Aruba controllers and are having a bit of difficulty with packet drops in our OR areas. The network response times are fine (new HP network 10G) up to the controllers, and the wireless is working fine in some areas, but the OR's and PACU areas see high ping times (hundreds of ms) with packet drops running about 8%. Citrix is freezing and dropping the clients due to the delay.

    We purchased the DBx device along with Channelizer to see if we could locate interference. I ran a few scans, but since I'm new to the software, I would like some guidance if possible. Here is a scan of the center core which is a hallway surrounded by operating rooms:

    Core-WirelessOFF.wsx

    I ran another scan outside the core next to the booking area and see what looks like alot of bluetooth activity:

    ORBooking.wsx

    I'm not really sure how to approach these scans. Should I just try and find a channel that isn't too busy and set my AP's for that channel only? The Aruba controllers should automatically find the channel that isn't busy and switch to it, but I'm thinking there is just noise everywhere.

    Any ideas or guidance would be appreciated. I'm not sure if I scanned for a long enough amount of time, or if any settings should be used for better results.

    Thanks in advance.

  2. #2

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    In the Core-Wireless capture, what is on Channel 6? The Bluetooth is definitely present but does anything in the hospital require it? Whats a typical distance between the wireless carts and the AP? I think the capture was good, you just need to identify the transmitters. Do you have the directional antenna from MetaGeek?

  3. #3

    Default

    One of my access points that I was near when I did the capture is on Channel 6. Carts typically are about 20 - 30 feet from the nearest AP. I don't have the directional antenna, I probably should get one, we have many devices that just "appear" without going through IT, our doctors love their toys.

  4. #4

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    Education might be your first step. Tell everyone to turn off the wifi and bluetooth on their phones and personal devices before they enter the hospital. Aside from the possible interference its a legitimate security concern.

  5. #5

    Default

    Quote Originally Posted by vinster789 View Post

    I'm not really sure how to approach these scans. Should I just try and find a channel that isn't too busy and set my AP's for that channel only? The Aruba controllers should automatically find the channel that isn't busy and switch to it, but I'm thinking there is just noise everywhere.
    I want to touch up on this a bit. First off, when you have the AP's set to auto, there are no super special algorithms that allows the AP to detect the best possible channel. When you have the AP set to auto, it will shift between either channels 1, 6, or 11.

    When it comes to the first part where you are asking about channels. I want you to take a loot at this diagram I made for you to help you get a better idea of the way channels work.
    Click image for larger version. 

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  6. #6

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    Thanks for the replies. The AP's do use 1, 6, or 11 only so the controller wouldn't set them to any other channels. I do see other AP's on the other channels I have to find (I ordered the directional antenna). We found the issue in the OR's, it is 2 fixed frequency video signals that are taking up 80 to 90% of the channel bandwidth on 6 and 11. For some reason it wasn't showing up on my Chanalyzer scan, they showed up when I figured out how to turn an AP into a spectrum monitor on the Aruba controller. I'm going to need to wait for the directional antenna to find the source as nobody know what I'm talking about when I go there and ask what may be the source.

    We are also finding alot of microwave oven interference on the floors, every nurses station has a microwave. That's going to be a fun one to solve

    Thanks again, love the site!!

  7. #7

    Default

    vinster,

    You may not have saw the video frequencies if there was a lot happening on those channels. For instance, if you have 10 AP's on channel 1, you might be able to see that there are more than one, but you won't be able to tell how many exactly without the Networks Table tab.

    And oh yes, microwaves are always fun to deal with. I had a support question from a restaurant about why their WiFi was so slow when the place got busy. I found out that they had 10 microwaves that were always running during rush hours to fill people's orders. I got them to switch to 5Ghz to help with their issue.

    Anyhow, no problem. We are all here to help each other out. WiFi is some tricky stuff and a huge pain sometimes

    Stephen

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