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VPN destroys speed
Our rads are getting 400-700 Mbps download times at home from their ISPs.
Through the VPN we test at around 120-130 Mbps download times,
but this slows down to 1 (one) to 30 or 35 Mbps when opening or closing a cross sectional exam.
What gives? There’s a baseline VPN bottleneck destroying 75% of our speed, then another 75% or more during the actual opening and closing of exams.
Thanks in advance for any insight. PM me if desired. -
8 Replies
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Cross sectional exams have a lot of small files. Depending on your PACS, look at your settings for simultaneous file transfers. You might increase that. Consider a hardware vpn solution like Meraki.
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What test are you using? Something like fast com? If so thats not what I would call a relevant test of speed between your pacs and home PC. If your VPNd and run that type of test your really testing your hospitals ISP.
Probably a better test would be to take a large file and just FTP it from server to home and vice versa to see how long it takes.
Also I think many people are thinking whatever service they have is the speed your going to get from your hospital. Really theres a lot more people working remote. The place probably only has X amount of bandwidth theyre purchasing. So your in contention with other people for the same resource.
The actuall hardware running your pacs can also probably only output the data at a certain rate also.
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VPNs destroy speed, to quote a popular insurance commercial ‘because that’s what you do if you are a VPN’.
Unless you have a dedicated VPN gateway that only handles radiology, you are lumped in with the general hospital VPN traffic which are people like billers, billing analysts, billing analyst supervisors, materials clerks, lucy the secretary etc. who work from home. The settings on the VPN are some standard pre-set that is supposed to make every user equally unhappy. OF course, the network traffic for some billing desktop or for some secretary to access some text files is different from what you need.
What you need to find is ‘Big Jim’, he works in hospital IT and is the only one who speaks fluent Cisco. Also, because he has no social life, he is the onlye one who read the documentation on that VPN server the hospital bought. ‘Big Jim’ works from home since the beginning of the pandemic (because he is hig-risk 😉 ), so getting hold of him can be a challenge. If you explain your needs to him with the necessary level of deference and prostration, he may be able to tweak the settings on the hospitals VPN server to destroy less of the bandwidth allocated to your connection. It can be sensitive to file size and at times it needs to ‘phone home’ many times during the connection so speed going both ways is important. Unfortunately, you will notice that 9 months from now you are back to square1 because some update on the VPN server bounced you back to ‘Lucy the secretary’ settings…..-
Insert Billy Madison scene.
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We put in a dedicated (Sonicwall) gateway appliance for our remote rads, to separate their traffic from the rest of the facility. This has greatly improved performance remotely, and makes reading tomo studies much easier
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I use LAN Speed Test Lite. It can write a file to a UNC path at the PACS or some other server in the same network and then download it back. When it completes it will give you download and upload speeds. It gives a great ballpark figure of your effective bandwidth. It is not technically a 100% reliable test, since it cannot factor in latency if your network traffic is chatty. But once you got a baseline, if you retest and your numbers are half or a third of your normal you can blame the unreliability of the internet.
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Have meraki – still throttles fast.com from 200 down to 30 on my home work station
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There are Meraki models that have different throughput speeds. I have one that can handle up to 200 mbps. In practice I can move images at about 150 mbps.
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