1. Information Systems for Health:
Health Informatics in Low- and Middle-Income Countries
Short Course for Health Information System Professionals
Information Systems for Health:
Networks

2. Networks Learning Objectives Define a communication network
Explain the purposes and benefits of a communication network
Explain the Internet and World Wide Web, their histories, and their structures
Describe different ways of connecting to the Internet
The objectives for this unit on Networks are to:
Define what a communication network is
Explain the purposes and benefits of a communication network
Explain the Internet and World Wide Web, their histories, and their structures
Describe ways to connect to the Internet

3. What is a network?
“…a collection of computers and devices connected by communications channels that facilitates communications among users and allows users to share resources with other users.”
—Wikipedia, 2011
It is appropriate to begin this discussion with the definition of a network. According to Wikipedia, a network is “a collection of computers and devices connected by communications channels that facilitates communication among users. It allows users to share resources with other users."

4. What is a network? In plain English:
A network is made up of computers, printers, other devices, and some sort of media (cabling; wireless) that allows all of these devices to communicate with one another.
In plain English, a network comprises computers, printers, and other devices, along with some sort of media—“media” being the cabling and/or the ability to communicate wirelessly, which allows all of the devices to communicate with one another.

5. Modern Network Example
A site-to-site network with support for remote users
To visualize what a moderate-sized network would look like, examine the figure on the screen where you will see two regional offices that are connected to the head office.
Remote users (employees who work at home or travel as part of their job) also need to connect to the head office.
Note that all users are connecting through the Internet and that the Internet service provider’s or ISP’s devices shown in the figure are interconnecting all of the sites. Additionally, the routers at the regional offices are connecting to a router at the head office.
—Ludovic.ferre, 2010

6. Why networks? Share hardware Printer, scanner, data storage devices
Share software
Software installed on a server to reduce cost
Share files
Images, spreadsheets, documents
Share patient data
Communicate
, network phones, live chat, instant messaging
What is the motivation behind creating networks?
Connecting devices into networks provides a number of significant benefits. For example, many users can share hardware such as printers, scanners, and data storage devices.
The users can also simultaneously access software installed on servers, reducing the cost of business.
And, through networks, people can exchange and instant messages, chat, and share files such as images, documents, and spreadsheets.

7. Networks Decrease Cost
Printed documentation moved to a web server
No longer need to update physically: can update web page and notify users of changes
done electronically and replaces paper documents
Easier to keep device software current
No need to physically visit each device to manage it or upgrade software
It is important to point out that networks decrease costs for business, individuals, and governments. For example, what was once printed documentation can now be located digitally on a web server. This means that users no longer need to update documentation physically; instead, a webpage is updated and users can be automatically notified of the changes.
In the past, technical support teams printed documentation and kept copies at their desks so that they could answer questions that came in from customers. If the documentation changed, someone had to reprint and distribute the documentation to perhaps 200 technical support agents. Web servers have eliminated that effort and cost.
Networking has also brought us as a form of electronic paperwork, eliminating the need for interoffice paper memos and mailing costs, for example.
Finally, networks make it easier to keep device software current. Network administrators no longer need to physically visit each device to manage it or to upgrade its software. Through networking, administrators at the home office can locate a remote device, connect to that device, and make changes to it without ever leaving the office.

8. Networks Serve Patients
Hospitals can store all patient data in one common network database, improving quality of care.
Medical staff and patients can access electronic medical records stored in a network database.
Patients can also access important data.
Hospitals can store all patient data in one common network database, which improves the quality of care.
Medical staff and patients can access electronic medical records stored in a network database, as well.
In addition, a patient can easily locate the name of the nurse on another screen.
Again, all of this is accomplished by a network.

9. What is the Internet?
“The Internet is a global system of interconnected computer networks that use the Internet protocol suite (TCP/IP) to link billions of devices worldwide.” (Wikipedia, 2016)
In other words, the Internet is a large network made up of many smaller networks.
But what exactly is the Internet?
According to Wikipedia, “The Internet is a global system of interconnected computer networks that use the Internet protocol suite, transmission control protocol—Internet Protocol, or TCP/IP—to serve billions of users worldwide.”
So, the Internet is a large network made up of many smaller networks. For example, one small city may connect to other small cities, creating a regional network. That regional network might connect to another regional network, creating an ever-larger network and so on.

10. The Internet Today
The Internet continues to grow, especially since the mid-1990s.
In 1995, approximately 16 million people were using the Internet.
In 2015, about 3.17 billion people were using the Internet (International Telecommunication Union).
The world quickly saw the benefits of an Internet, so the Internet continued to grow, especially from the mid-’90s through today.
In 1995, for example, an estimated 16 million people were using the Internet.
In 2015, as estimated by International Telecommunication Union, more than 3.17 billion people were using the Internet.

11. HTML—The Language of the Web
Web pages are text files written in hypertext markup language (HTML): a programming language.
HTML example for a simple web page:
The previous slide pointed out that the web server sends HTML coding back to the browser, which translates that HTML coding for display on the user’s monitor. Therefore, HTML is the language of the web.
Web pages are text files written in the HTML programming language. An example of HTML is shown in the figure on the left side of this slide.
Notice the HTML tags enclosed in brackets. This code outputs the web page shown on the right side of the slide.
To reproduce the web page output shown above, all you would have to do is type the HTML code into a Notepad document, save the document with the file extension of either HTM or HTML, then double-click on the file to open it.

12. Who owns the web? No entity owns the Internet.
Individuals and organizations own the devices that connect to the Internet.
People and organizations also own the content of the Internet.
Google’s experience in China is an example.
See Wikipedia’s web page titled “Internet Censorship in China.”
This leads to the question, “Who owns the web?” The answer is that no entity owns the Internet. People and organizations own the devices that connect to the Internet and form the World Wide Web. In fact, these people and organizations also own the content on the web.
However, when Google encountered Chinese censorship, it was clear that a country can repress what its citizens read. There is an ongoing discussion of this issue at Wikipedia’s web page titled Internet Censorship in China.

13. Internet Service Providers
Users connect to the Internet through Internet Service Providers (ISPs).
ISPs are organized as local, regional, and national providers.
Internet Service Providers, or ISPs (eye-ess-peez), connect users to the Internet. Typically, a user has a contract with an ISP that allows connection to the Internet using the ISP’s services. For example, a computer user at home who wants access to the Internet needs to buy a service plan from an ISP in order to connect to the Internet.
In fact, access to the Internet globally revolves around the use of ISPs. As shown here, ISPs are organized as local, regional, and national providers and, in some cases, even international providers.
A tier 1 ISP is a large national or international provider.
A tier 2, or regional, ISP connects a local ISP to tier 1 ISPs.
A tier 3 ISP is a local internet service provider.
—Ludovic.ferre, 2010

14. Data Transmission Rate—Bandwidth
The data transmission rate (speed) of a network is characterized by bandwidth and throughput.
Bandwidth is the greatest amount of data that can be carried between two points in a given period (usually one second).
Bandwidth is usually expressed in bits per second, kilobits per second (Kbps), megabits per second (Mbps), or gigabits per second (Gbps).
One of the most important characteristics of a network’s performance is how fast data can be transmitted between its components. The data transmission rate of a network connection, or in more casual terms, the speed of a network, is characterized in terms of bandwidth and throughput.
Bandwidth is the greatest amount of data that can be carried between two points in a given period: usually one second.
Common bandwidth units are bits per second or bps, megabits per second or Mbps, or gigabits per second, Gbps.

15. Data Transmission Rate— Bandwidth and Throughput
The data transmission rate (speed) of a network is characterized by bandwidth and throughput.
Bandwidth is the greatest amount of data that can be carried between two points in a given period (usually a second).
Throughput is the amount of bandwidth available for network communications.
Throughput is the amount of bandwidth that is available for actual network communications.

16. Data Transmission Rate— Network Performance
Network performance can be degraded by several factors:
Required network traffic
Packet loss
Latency
Example:
If bandwidth on your cabled network is 100 Mbps, throughput is usually about 70 Mbps, because of communication overhead
Network performance can be degraded by a number of factors, such as other required network traffic, packet loss, or latency. Therefore, network throughput can be significantly lower than its bandwidth. For example, the bandwidth of a home network might be 100 megabits per second using typical network cabling. Typical throughput, however, is usually only about 70 megabits per second. Therefore, this network loses about a third of its bandwidth because of what is referred to as communication overhead.

17. How Devices Connect to a Network
Wired or wireless connections
Network may or may not be connected to the Internet
An Internet connection requires an ISP
An Intranet is a private network and does not connect to the Internet
Accessible only by the devices within the organization
May connect offices together, regardless of their location, without providing Internet access
Devices such as scanners, printers, computers, and mobile devices connect to a network using a wired and/or wireless connection. The network to which those devices are connected may or may not be connected to the Internet. An Internet connection requires the use of an ISP.
In contrast, an intranet is a private network and does not connect a device to the Internet. For example, the network at an organization or company is an example of an intranet. It is accessible only by the devices within the organization that owns the network. An intranet can connect remotely located offices without providing Internet access.

18. Wired Connection Types
Dial-up: Copper phone lines connected to an ISP’s modem
Limited to 56 Kbps, the slowest connection type
Broadband: Higher-quality copper phone lines or coaxial cable
Faster than dialup: ~768 Kbps and higher
Fiber-optic: Transmitting pulses of light through an optical fiber
~ 500 Mbps
Existing wired connection technologies are dialup, broadband, and fiber optic connections.
Dial-up connections use copper phone lines to connect to an ISP's modem. This speed, or bandwidth, is limited to 56 kilobits per second. This is the slowest way of connecting to the Internet.
Broadband connections have higher quality copper phone lines, perhaps even coaxial cable, also known as coax cable.
Broadband is faster than dial-up, and runs in the approximate speed range of 768 kilobits per second or higher.
Fiber-optic communications transmit information by sending pulses of light through an optical fiber. Fiber optic’s speed range is around 500 megabits per second.

19. Wireless Connections Wi-Fi: Local area network
Connects laptops and mobile devices to a wireless access point, which in turn connects to the Internet through a wired network
Used extensively by hotels and airports
Speeds range from 1 Mbps to 200+ Mbps, depending on a variety of factors
Satellite: Uses communication satellites
Speed ~ 50 Mbps
Wireless networking technologies are Wi-Fi, satellite Internet, and a number of technologies developed for mobile devices and mobile telecommunications, such as 3G, 4G, 5G, and LTE.
Wi-Fi refers to technology that allows devices to connect wirelessly to a local network.
Wi-Fi is typically used to connect laptops to a wireless application protocol (WAP), which in turn is connected to the wired network, usually through a switch or through some type of an ISP router.
Wi-Fi is used frequently in hotels and airports. In fact, in most hotels, users are able to gain access to the Internet using some type of a Wi-Fi connection. Many small regional airports provide free Wi-Fi access to passengers waiting in terminals, whereas larger airports view this as a revenue opportunity and charge for access.
Wi-Fi speeds can range anywhere from 1 megabit per second, which is extremely slow, to well over 200 megabits per second. Wireless networking equipment functions in one or more wireless standards such as a; b; g; or n. Each wireless standard specifies, among other things, the maximum theoretical bandwidth at which it operates.
If the standard is g, for example, then bandwidth most likely is somewhere around 54 megabits per second, depending on the laptop’s and/or the wireless device's proximity to the WAP. The farther away that a user is from a WAP, the lower the network speed or bandwidth will be. If the connection to a WAP is at 1 megabit per second, the user is probably too far away and needs to move closer.

20. Wireless Telephone Technology
1G, 2G, 2.5G, 3G, 4G, and 5G are generations of wireless telephone technology
3G: Third generation technology introduced in 2001
Data transmission speed is up to 2 Mbps
High-speed web
Video conferencing
TV streaming
Wideband Code Division Multiple Access standard
Another way to connect to the Internet is to use wireless telephone technology. 1G, 2G, 2.5G, 3G, 4G, and 5G are generations of wireless telephone technology that were introduced consecutively as the technology developed. Most of the devices in 2016 operate on 3G or 4G. 5G is undergoing testing and is expected to be deployed soon.
3G is the 3rd generation technology that was introduced in It achieves data transmission speeds of up to 2 megabits per second and allows high-speed web connection, video conferencing, and TV streaming. It adheres to the wideband Code-Division Multiple Access, or WCDMA, standard.

21. Wireless Telephone Technology
4G: Fourth generation, introduced in 2008
Capable of providing speeds of 100 Mbps to 1 Gbps
Mobile multimedia
Customized personal services
Wireless interoperability microwave access and long- term evolution standards
5G: Next major step in the evolution of mobile telecommunications
Undergoing testing (2016)
Expected to be widely available by 2020
4G is the 4th generation technology; it was introduced in It achieves speed of up to 100 megabits per second to 1 gigabit per second, and consequently offers even more in terms of web communication, teleconferencing, and video streaming. There are two 4G standards in operation: WiMAX and LTE.
5G is the next major step in the evolution of mobile telecommunications. As of early 2016 it was undergoing testing and was expected to become widely available by the year 2020.

22. Networks
Summary
Defined a communication network and explained its purposes and benefits
Explained the Internet and the World Wide Web, their histories, and their structures
Described ways to connect to the Internet
This concludes Lecture A on Networks.
In summary, this lecture defined what a communication network is and explained its purposes and benefits. It gave an introduction to the Internet and World Wide Web, and described different ways to connect to the Internet.

23. Networks
References
Wikipedia. (n.d.). Computer network. Retrieved from Images Ludovic.ferre. (2010, April 22). Site-to-site network topology [online image]. Retrieved from Network_overview.svg. Licensed through Creative Commons Attribution- ShareAlike 3.0 Unported License Ludovic.ferre. (2010, April 16). Tier 1 and 2 ISP interconnections [online image]. Retrieved from Distribution_%26_Core.svg. Licensed through Creative Commons Attribution- ShareAlike 3.0 Unported License
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24. This material was developed by Oregon Health & Science University, funded by the Department of Health and Human Services, Office of the National Coordinator for Health Information Technology under Award Number 90WT0001.
This presentation was produced with the support of the United States Agency for International Development (USAID) under the terms of MEASURE Evaluation cooperative agreement AID-OAA-L MEASURE Evaluation is implemented by the Carolina Population Center, University of North Carolina at Chapel Hill in partnership with ICF International; John Snow, Inc.; Management Sciences for Health; Palladium; and Tulane University. Views expressed are not necessarily those of USAID or the United States government.
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