Transcript Chapters 5 and 6 Networks - MCST-CS

Chapter 5 Networks
Learning Objectives
After reading this chapter the reader should be able to:
• Understand the importance of networks in the field
of medicine
• Compare and contrast wired and wireless LANs
• Describe the newest wireless broadband networks
and their significance
• A network is a group of computers that are linked
together in order to share information.
• Although a majority of medical data resides in
silos, there is a distinct need to share data
between offices, hospitals, insurers, health
information organizations, etc.
• A network can share patient information as well
as provide Internet access for multiple users.
• Networks can be small, connecting just several
computers in a clinician’s office or very large,
connecting computers in an entire organization.
There are several ways to access the Internet:
dial-up modem, WiFi, satellite and broadband access
using a Digital Subscription Line (DSL), cable modem or T1
lines. The most common type of DSL is Asymmetric DSL
(ADSL) which means that the upload speed is slower than
the download speeds, because residential users utilize
the download function more than the upload function.
Symmetric DSL is also available and features similar
upload and download speeds. Cable modem often begins
with fiber optic transmission to the building, with coaxial
cable run internally.
The following are network data transfer speeds
based on the different technologies.
The Internet Protocol (IP) is a standard that
segments data, voice and video into packets
with unique destination addresses. Routers read
the address of the packet and forward it towards
its destination. Transmission performance is
affected by the following:
Factors affecting transmission
performance
• Bandwidth: is the size of the pipe to transmit packets. In reality,
networks should have bandwidth excess to operate optimally
• Packet loss: packets may rarely fail to reach their destination. The IP
Transmission Control Protocol (TCP) makes sure a packet reaches its
destination or re-sends it. The User Datagram Protocol (UDP) does not
guarantee delivery and is used with, for example, live streaming video.
In this case the user would not want the transmission held up for one
packet
• End-to-end delay: is the latency or delay in receiving a packet. With
fiber optics the latency is minimal because the transmission occurs at
the speed of light
• Jitter: is the random variation in packet delay and reflects Internet
spikes in activity
Network Types
Networks are named based on connection method,
as well as configuration or size. As an example, a
network can be connected by fiber optic cable,
Ethernet or wireless. Networks can also be
described by different configurations or topologies.
They can be connected to a common backbone
or bus, in a star configuration using a central hub or
a ring configuration.
In this chapter we will describe networks by size or
scale.
1. Personal Area Networks (PANs)
2. Local Area Networks (LANs):
• Wired networks: To connect to the Internet through
your Internet Service Provider (ISP)
you have several options. Modem: you can use the older
and slower modem technology to connect your computer
to the Internet over routine phone lines.
Ethernet is a network protocol and most networks are
connected by fiber or twisted-pair/copper wire
connections.
Ethernet networks are faster, less expensive and more
secure than wireless networks.
• Wireless (WiFi) networks (WLANs):
Wireless networks have become much cheaper
and easier to install so many offices and
hospitals have opted to go wireless to allow
laptop/tablet PCs and smartphones in exam and
patient rooms.
In general, wireless is slower than cable and is
more expensive, but does not require hubs or
switches.
3. Wide Area Networks (WANs): Cross city, state or
national borders. The Internet could be considered a
WAN and is often used to connect LANs together.
4. Global Area Networks (GANs): The problem with
broadband technology is that it is expensive
and the problem with WiFi is that it may result in spotty
coverage.
These shortcomings have created a new initiative known
as Worldwide Interoperability for Microwave Access
(WiMax), using the IEEE 802.16 standard. The network
will be known as a global area network (GAN).
5. Virtual Private Networks (VPNs): If a clinician
desires access from home to his/her electronic
health record, one option is a VPN. In this case your
home computer is the client and the computer at
work you are trying to access is the VPN server.
The Internet is the means of connection and VPN
will work with wired or wireless LANs.
Authentication and overall security are key
elements of setting up remote access to someone
else’s computer network.
Key Points
• Clinicians who use client-server based
electronic health records need to establish a
wired or wireless office network
• Wireless networks have become more
attractive due to faster speeds and lower prices
• Wireless broadband is around the corner and
will make Internet access faster and more widely
available
Conclusion
Hospitals’ and clinicians’ offices rely on a variety of
networks to connect hardware, share data/images and
access the Internet. In spite of initial cost, most elements
of the various networks discussed continue to improve in
terms of speed and cost.
Many clinician offices will require a network expert to
ensure proper installation and maintenance. Wireless
technology (WiFi) has become commonplace in many
medical offices and hospitals. When wireless broadband
(WiMax- LTE) becomes cost effective and widely available
it may become the network mode of choice. Network
security will continue to be an important issue regardless
of mode.