the path to paperless
Designing the Office Network
Making Choices: LAN or WAN? Wired vs. Wireless?
By Peter J. Polack, M.D., F.A.C.S.

Whether or not you use electronic medical records (EMR), chances are you're already using a computerized system for scheduling and/or billing. And unless you only have one computer in the office, chances are that the computers are connected by some sort of network.

When the complexity of a multi-user, multitasking EMR system is introduced into the office setting, the design and capabilities of the computer network become critical. And although I'm assuming that most practices will employ the services of an IT specialist or company, here I'll explain some of the commonly used concepts in designing the physical network.

Basics of Networking

LAN, WAN or MAN?

A LAN (local area network) connects network devices such as computers or printers across a small distance, such as within an office or school. The LAN then connects to other LANs, via network wire or a wireless connection, if short distances separate them, or via a WAN (wide area network) if the distances are greater.

In many cases, you can easily set up a small LAN using hardware available in consumer electronic stores, and software such as Windows XP. However, certain EPM/EMR software applications may have issues of compatibility with the networking hardware and operating system software. This should be checked before purchasing the EMR system.

In addition, if you expect to add users in the future, it's usually more cost- effective to buy multi-user licenses for the software rather than buying individual consumer software packages through a retail store.

When a WAN is Best

A WAN connects smaller networks such as LANs or MANs (metro area networks) in different places over a wider geographic area, such as between satellite offices. WANs are usually maintained by larger businesses or utility companies. The most popular WAN in the world today is the Internet. Apart from its entertainment value, the Internet can also be used to permit access to a company intranet where employees can communicate with each other or with practice resources, wherever in the world they may be. For EPM/EMR systems that need to run between satellite offices, a guaranteed high-bandwidth connection is critical to avoid the possibility of the practice grinding to a halt.

Topology and Bandwidth

The topology of a network is also important. It's the physical layout -- or shape -- of the network. Computers may be strung together in a bus or ring topology to minimize wiring, but if one part of the connection goes down, it may take down the entire network. A star topology requires more wiring but is less susceptible to systemwide failure; however, the number of devices you can connect is limited. Larger networks employ a tree or mesh topology which offer redundancy and allow for future expandability.

The bandwidth of the network is the capacity of data that it can carry. It is usually expressed in bits per second (bps). Connection speeds can vary from 56 kilobits per second (kbps), such as with a dial-up modem, to millions of bits per second (mbps). However, the actual bandwidth of a network connection may be limited by the hardware, or even the software used. This is important to know because the overall speed of a network can be drastically reduced once multiple users are trying to access patient information from an EMR system. A "super-fast" Internet connection between offices means nothing if the LAN speed is slow because of inadequate planning or underpowered hardware.

Wired vs. Wireless

In a typical paperless office, exam rooms would contain computers wired to the computer (server) running the EMR software. We currently use scribes for our paper charts, so some of our physicians will feel comfortable transitioning to scribes inputting data into a terminal. But some of our physicians may prefer entering information, including drawings, into handheld wireless devices, carrying them from room to room. Wireless networking brings up a whole host of issues that must be addressed:

Bandwidth. Your LAN may have high bandwidth, but the speed with which you can access the software may be limited by the speed of your wireless connection.

Strength of signal. We have often found that wireless access points (devices wired to the network that communicate with wireless devices) have less-than-advertised ranges when placed in a typical office setting with its multitude of walls.

Fat client vs. thin client. Will you use a wireless laptop to run the software directly via a wireless connection (fat client) or will the wireless device "virtually" run the software via a wireless remote connection (thin client)? Because disconnections are a fact of life with wireless networks, the thin client solution has the advantage of allowing the software to continue running should this happen and letting you pick up where you left off. With a fat client solution, a break in your wireless connection can cause your software to crash.

K Security. Malicious hackers known as "crackers" can wreak havoc on your network if it isn't properly secured, simply by driving by your office with a laptop. Even basic wireless access points come with built-in security protocols, which can easily be enabled, though few businesses take advantage of this. If your network is distributed among different locations or across the Internet, more layers of protection will be required. Your IT consultant can advise you on your options.

Next: Designing the Logical Network

Peter J. Polack, M.D., F.A.C.S., is co-managing partner for Ocala Eye, PA, and a specialist in cornea, external disease and refractive surgery. Founded in 1971, Ocala Eye is a seven-partner, multisubspecialty ophthalmology practice located in Ocala, Fla. The practice, which has five locations including an ASC and laser center, has 120 employees. He can be reached via e-mail at ppolack@ocalaeye.com.

In a multipart series, Dr. Polack is describing how a seven-partner practice, Ocala Eye in Ocala, Fla., with five locations and 120 employees, makes the major transition from paper medical records to EMR. During the course of the series, Dr. Polack will provide readers with a "real-time" look at how the implementation is progressing. This is part 5 of the series.