September 17, 2013

EMR over Wi-Fi – A Prescription for Wireless Success


Healthcare reform brought a number of changes to the industry in an incredibly short period of time.  One of the most significant changes was the conversion to electronic medical records (EMR) and the requirement to access information over Wi-Fi .  There are countless hospitals deploying and upgrading their EMR systems.  One common concern is network performance and more specifically Wi-Fi network performance.  With this in mind, it may be a good time to up your Wi-Fi know how before any performance concerns come up.   In this blog I will cover 3 key areas to focus on when troubleshooting EMR performance on a wireless LAN.

#1 Upgrade client device drivers

I have lost count how many times in my career I have overlooked something as simple as upgrading drivers.  This is a great first step in troubleshooting application performance over a WLAN.  WiFi is a continually evolving technology with a lot of moving parts and the client devices can have a huge impact on application performance.  Client driver settings should be standardized whenever possible.  Settings to pay attention to are band preference, power save mode, transmit power and roaming aggressiveness.  Each of these setting can vary from network to network depending on a number of factors.  I always start with the release notes from the wireless cards driver updates to find bug fixes.  I once was troubleshooting a “wireless problem” that would cause the client wireless to cease working.  After a week of packet captures, site surveys, and performance testing, I found the exact issue I was observing clearly spelled out in a newer drivers bug fixes list.  Sometimes the problems are in plan site.  Always upgrade first and ask question later.

#2 Reduce Retries

In order for a “wireless network design” problem to exist there must be retransmissions.   Any commercial WiFi protocol analyzer will be able to report retries.  A general rule of thumb is to keep retries below 10%.  Here is a list of things to check to reduce retries:

  • Target a signal level of -67 dBm

  • Ensure adjacent AP’s are on different channels

  • Us a spectrum analyzer to find non-WiFi interference

#3 Reduce Overhead

Lastly, WiFi networks have overhead in the form of management and control traffic.  While it is impossible to eliminate overhead here are a few best practices to reduce it:

  • Minimize the number of SSID’s used on a WLAN (ideally less than 3)

  • Replace or eliminate 802.11a and 802.11b client devices where possible

  • Raise the minimum data rates to 12 or 24 Mbps

The network can get a lot of blame of application performance.  Empowering yourself with the right knowledge, tools, and processes will ensure that you can confidently resolve performance problems when they arise.


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Extreme Marketing Team

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