Wireless Access

We are having an issue at our college campus Health Services building, where the doctors and nurses are using an RDP session into a medical server. One doctor for example, when she moves from her office to the exam room, she often loses the connection. This has been an ongoing issue at this building and I am hoping someone might be able to shed some light on potential causes.

There is another issue on campus involving some iPads that are connected via our Secure WiFi and are using our VPN to be behind the firewall, since they are used in the Counseling Center for filling out sensitive forms. The problem here is that the VPN disconnects due to "no network connection" (or something similar to that), and it is not possible to reconnect the WiFi and VPN without exiting the app (KioskPro Lite), which loses all data in the form. We are unsure if this is related to the Health Services issue, but it seems to be consistent in that building, since we have two Counseling Centers and they swapped iPads and the problem persisted in the same one. That building has two AP-325s (one on each floor), and is fairly small.

Things that may be helpful to know:

-We have an Aruba "Master" controller as well as two "Local" controllers

-We use all Cisco gigabit ethernet switches with 10gb fiber uplinks

-We cleaned the fibers relating to the controllers during a break between semesters.

-We have a gigabit connection to the rest of the internet.

-The doctors are using our Secure SSID or the Eduroam SSID (which is functionally identical)

-The building (Health Services) has 7 indoor AP-225's in a single group, all using the same controller (as well as an outdoor AP-175P in the OutdoorAP group).

-We have increased the minimum data rates so that the lower ones (I believe 1 and 2 mbps connections) are no longer available, to reduce sticky clients.

-I put a support call into Aruba TAC about another issue, and we enabled MPDU Aggregation, which was causing our wireless speeds throughout campus to hover around 45-50mbps (after enabling, they went as high as 450-500mbps).

-The Health Services building is wood structure with drywall, has two floors (only above one half), and is not very big (two floors on one side, just one floor on the other).

-There seems to be sufficient coverage in Health Services, as there is an AP directly above the doctor's office, one in the lounge area she walks through, and one in the exam room itself.

-These problems seem isolated to their respective buildings, but have been ongoing for some time now.

Please let me know if further information is needed. I would greatly appreciate any help!

If you have done all the work you mentioned, as well as contacted TAC, please take time to do a simple test:

Do a continuous ping to the device from a switch or a wired pice of equipment like the default gateway.  Have the doctor take the prescribed path and see if pings are dropped and at what point.  That might give you an indication of if connectivity is being dropped at the wireless level.  If few or no pings are dropped, you could have a different issue.

Also, does the device maintain the same ip address from the exam room to the office?

Colin,

I knew I'd forget to mention something! We have done several tests, though none from the device itself:

-We took a Macbook and put it behind the firewall VPN, on WiFi, at the Counseling Center, similar to the iPads in use. We ran a continuous ping to its firewalled IP address for 4+ hours and didn't see any disconnects. I should note that the students at Counseling Center take the iPad, sit down, and fill out the form for 30+ minutes. They don't physically move around during the time that it has been disconnecting.

-We did a PingPlotter test at Health Services, pinging the RDP server's pingable address. We didn't lose any local packets, and the few we did lose were at Level3 and it was shortly after the DDoS attack that affected the East Coast USA, so may have been related to that. I haven't had the opportunity to run futher ping tests there, but it seems to mostly happen when the doctor moves from her office to the exam room, and it's not always consistent if/when it happens. I have seen another nurse's computer drop the session while she had it on a table and it had been there for a few minutes already. Obviously I have ensured the computer did not go to sleep, the lid was open, there's no ethernet-to-wifi handoff going on (originally she had an Ethernet cable to her docking station but we disconnected that).

-The device IP has not changed. According to the lookup table, it appears to have had the same IP since 2015.

-We have also used a Fluke AirCheck to ensure there is a good SNR and coverage throughout the path taken.

There are a number of things you are discussing here.  I am discussing pinging the device from the closest wired default gateway continuously to see if there are any disconnects during motion or during an incident.  Theoretically if no pings are dropped, it is not the wireless infrastructure, specifically, and you might have to look deeper.

Alternatively, you could initiate a packet capture of that device on the controller that is decrypted, to the controller's local filesystem to see if if there is a delay in packet processing that matches your incident.  You should use the article here:  http://community.arubanetworks.com/t5/Controller-Based-WLANs/HOW-TO-DO-DATAPATH-PACKET-CAPTURE-FOR-WIRELESS-CLIENT-FROM/ta-p/179940 to setup that packet capture, have the client imitate behavior that creates an issue, collect the packet capture and examine the traffic pattern of the RDP.

Again, you are talking about a whole range of things; you might just want to focus on a specific thing like the RDP connection that is dropping on a specific path, first..

Working on a similar issue as what was described. We noticed that it only seemed to effect clients that were on 2.4ghz when roaming.

KatTheFoxtaur,

Is that the case or that does not match your situation?  You have quite a few variables.

Colin,

It does appear that the client is currently using the 2.4GHz N radio. I am not sure what the history looks like as far as which radios she has been using.

I am awaiting reply from her to see if she has still been having the issue.

Let's focus on the RDP disconnecting situation. I can open a separate post for the other one (the VPN disconnecting issue) if that's preferred. I am not sure what "variables" you are referring to - please advise what I can clarify.

I am not sure that the band should matter.

The "variables" are the VPN devices.  That would involve other devices downstream that we would not have visibility of..  We can talk about them in the same post, but one at a time.

Do you have Airwave?  That would tell you on what band the user was on throughout the day...