1. Component 4: Introduction to Information and Computer Science Unit 7: Networks & Networking Lecture 2
Welcome to Component 4, which, as you know, is entitled "Introduction to Information and Computer Science."
This is specifically Unit 7, Part 2, which has the title "Networks and Networking."
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 IU24OC

2. Health IT Workforce Curriculum Version 2.0/Spring 2011
Unit Objectives
Understand the history of networks and their evolution.
List and describe the various types of network communications.
List and describe the various forms of network addressing, including DNS.
List and define the different types of networks.
Describe different network topologies.
List and describe different network standards and protocols.
Describe wireless communication.
List and describe network hardware.
Explain logical networking model concepts.
In this unit, we cover a number of objectives, all of which are listed on the slide.
We discussed unit objectives 1 and 2 in part 1.
In Part 2, we focus on concepts related to the third objective listed. However I will read all of the objectives listed.
Component 4/Unit 7-2
Health IT Workforce Curriculum Version 2.0/Spring 2011

3. Health IT Workforce Curriculum Version 2.0/Spring 2011
IP Addressing Basics
All Internet communication utilizes IP addressing.
The Internet expects each communicating device (known as a host) to possess an Internet Protocol (IP) address.
Two versions of IP exist in today’s networks:
IP version 4 has been around for nearly 50 years and is being replaced by IP version 6.
An example of a communicating device is your computer.
Your computer sends information to the Internet when you send an .
Your computer receives information from the Internet when you get an .
Component 4/Unit 7-2
Health IT Workforce Curriculum Version 2.0/Spring 2011

4. Health IT Workforce Curriculum Version 2.0/Spring 2011
IP Address Versions
IP version 4 (IPv4):
Consists of IP address and subnet mask:
IP address:
Subnet mask:
Means that this host is in the x network.
IPv4 addresses almost all used up.
ISPs and governments now migrating to new version of IP.
Private networks will probably stick with IPv4 long into the future.
Component 4/Unit 7-2
Health IT Workforce Curriculum Version 2.0/Spring 2011

5. Health IT Workforce Curriculum Version 2.0/Spring 2011
IP Address Versions
IP version 6 (IPv6):
Uses hexadecimal characters instead of decimal numbers like IPv4:
Valid characters are 0-9 and A-F (to represent numbers from 10 to 15).
Consists of IP address and prefix number:
IP address: fe80:0cd0:2414:dc09:e6f5:23b1:528f:7fe2
Prefix: /23
Means that this host has a local IP address.
IPv4 is currently being phased out by ISPs and the U.S. government as they move to IPv6.
IPv6 offers enough addresses to give every person on the planet thousands of IP addresses into the foreseeable future.
IP addressing – especially IPv6 – is a very complex topic.
Managers of servers, switches, and routers must be proficient in calculating and providing addresses to devices.
Others need to understand that IP addressing is required and that hosts in different IP addressed networks will not be able to communicate with each other without special rules programmed into routers. 
 A host with an IP address and subnet mask of , would not be able to communicate with a host addressed as ,
Component 4/Unit 7-2
Health IT Workforce Curriculum Version 2.0/Spring 2011

6. IPv4 Addressing Basics (cont’d)
Given:
IP address:
Subnet mask:
This network can legally have addresses in the range of through
Networking devices and software use and for routing and communication.
Valid numbers are in the range of
Almost all network communication uses IP addressing.
Routers are able to route network traffic using IP addressing.
Switches, by default, are not routers and don’t use the IP address. They use the media access control (MAC) address stamped on the NIC and forward network traffic to devices in their network only.
An IPv4 address is made up of four groups of numbers.
Devices see each group of four numbers as binary numbers.
For example, the decimal number 192 is represented as in binary.
The IP address tells you the exact address of a host.
The subnet mask is used to indicate the network in which the host resides through use of a process called “anding.”
ANDING has to do with binary mathematics and is beyond the scope of this unit.
Component 4/Unit 7-2
Health IT Workforce Curriculum Version 2.0/Spring 2011

7. LANs Use More Than IP Addressing
LAN communication uses IP and MAC addressing.
The MAC (Media Access Control) address is stamped on each installed NIC.
The MAC address is used by switches for intranet communications and has no meaning outside of that local network.
MAC addressing is used in all LAN communication.
Component 4/Unit 7-2
Health IT Workforce Curriculum Version 2.0/Spring 2011

8. Health IT Workforce Curriculum Version 2.0/Spring 2011
MAC Address Example
Output from a desktop computer:
Opened Command Prompt and ran “ipconfig /all” command.
IPv4 address is the IP address assigned to this NIC.
Physical address is the NIC’s MAC address.
MAC address
Leave the command prompt window open for an exercise on an upcoming slide.
IP address
Component 4/Unit 7-2
Health IT Workforce Curriculum Version 2.0/Spring 2011

9. How to Obtain an IP Address…
Some IP addresses can be purchased (or leased) and used by the owner of that IP address or IP address range.
These are referred to as public IP addresses.
Most IP addresses are public addresses.
Other IP address can be used by anyone.
These are referred to as private IP addresses.
Examples include , , and
IP addressing is beyond the scope of this unit.
Component 4/Unit 7-2
Health IT Workforce Curriculum Version 2.0/Spring 2011

10. Health IT Workforce Curriculum Version 2.0/Spring 2011
Domain Names
Networks and the Internet support the use of domain names.
Imagine trying to navigate the Internet using IP addresses and not names!
Since people remember names better than numbers, the Domain Naming System (DNS) was created.
Component 4/Unit 7-2
Health IT Workforce Curriculum Version 2.0/Spring 2011

11. Health IT Workforce Curriculum Version 2.0/Spring 2011
What is a Domain Name?
People and organizations can purchase a domain name from ICANN.
According to Wikipedia:
“A domain name is an identification label that defines a realm of administrative autonomy, authority, or control on the Internet, based on the Domain Name System (DNS).”
Domain names are made up of three pieces:
The domain name, indicates a government site with the purchased domain name of “whitehouse”, which is found on the WWW.
ICANN is the Internet Corporation for Assigned Names and Numbers.
Web site:
Anyone can buy any available domain name with any extension if they are willing to pay for it (and it's available).
Because an entity's URL ends with the “.org”, “.gov” or another extension (or top-level) domain name does not prove the entity's type.
Government entities own a number of domain names with the “.com” extension.
Component 4/Unit 7-2
Health IT Workforce Curriculum Version 2.0/Spring 2011

12. DNS - Another ISP Service
ISPs provide a first-level of DNS servers.
ISP DNS servers connect to global DNS root servers for help when they cannot resolve a name to an IP address.
Using an ISP’s DNS servers makes for a speedier browsing experience!
Component 4/Unit 7-2
Health IT Workforce Curriculum Version 2.0/Spring 2011

13. DNS & IP Work Well Together
DNS maps an IP address to a domain name.
When you visit your computer must first figure out this Web site’s IP address.
One IP address for this site is This Web site is probably associated with many IP addresses.
Domain name resolution is accomplished through the use of DNS servers, which are located throughout the world.
DNS is the Domain Naming System.
Do it!
With your command prompt window still open, type the command "ping [without the quotes].
To open a command prompt in Windows 7, click the Windows Home key on your keyboard, type "cmd" [without the quotes], and press enter.
Examine the output and note the IP address associated with this domain name. Is it different than the one shown in the slide (probably!)?
Component 4/Unit 7-2
Health IT Workforce Curriculum Version 2.0/Spring 2011

14. DNS & IP Work Well Together (cont’d)
All domain names are mapped to an IP address and stored on global and privately-owned DNS servers.
Global DNS servers are known as “root servers” and work together to map the globe’s names to their IP addresses.
When your browser learns the destination site’s IP address from the DNS server, communication begins!
DNS is the Domain Naming System.
Component 4/Unit 7-2
Health IT Workforce Curriculum Version 2.0/Spring 2011