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Engineering LibreTexts

5: Networking and Communication

  • Page ID
    17959
  • Learning Objectives

    Upon successful completion of this chapter, you will be able to:

    • understand the history and development of networking technologies;
    • define the key terms associated with networking technologies;
    • understand the importance of broadband technologies; and
    • describe organizational networking.

    Introduction

    In the early days of computing, computers were seen as devices for making calculations, storing data, and automating business processes. However, as the devices evolved, it became apparent that many of the functions of telecommunications could be integrated into the computer. During the 1980s, many organizations began combining their once-separate telecommunications and information systems departments into an Information Technology (IT) department. This ability for computers to communicate with one another and to facilitate communication between individuals and groups has had a major impact on the growth of computing over the past several decades.

    Computer networking began in the 1960s with the birth of the Internet. However, while the Internet and web were evolving, corporate networking was also taking shape in the form of local area networks and client-server computing. The Internet went commercial in 1994 as technologies began to pervade all areas of the organization. Today it would be unthinkable to have a computer that did not include communications capabilities. This chapter reviews the different technologies that have been put in place to enable this communications revolution.

    A Brief History of the Internet

    In the Beginning: ARPANET

    The story of the Internet, and networking in general, can be traced back to the late 1950s. The United States was in the depths of the Cold War with the USSR as each nation closely watched the other to determine which would gain a military or intelligence advantage. In 1957, the Soviets surprised the U.S. with the launch of Sputnik, propelling us into the space age. In response to Sputnik, the U.S. Government created the Advanced Research Projects Agency (ARPA), whose initial role was to ensure that the U.S. was not surprised again. It was from ARPA, now called DARPA ((Defense Advanced Research Projects Agency), that the Internet first sprang.

    ARPA was the center of computing research in the 1960s, but there was just one problem. Many of the computers could not communicate with each other. In 1968 ARPA sent out a request for proposals for a communication technology that would allow different computers located around the country to be integrated together into one network. Twelve companies responded to the request, and a company named Bolt, Beranek, and Newman (BBN) won the contract. They immediately began work and were able to complete the job just one year later.

    ARPA Net 1969

    Professor Len Kleinrock of UCLA along with a group of graduate students were the first to successfully send a transmission over the ARPANET. The event occurred on October 29, 1969 when they attempted to send the word “login” from their computer at UCLA to the Stanford Research Institute. You can read their actual notes. The first four nodes were at UCLA, University of California, Stanford, and the University of Utah.

    The Internet and the World Wide Web

    Over the next decade, the ARPANET grew and gained popularity. During this time, other networks also came into existence. Different organizations were connected to different networks. This led to a problem. The networks could not communicate with each other. Each network used its own proprietary language, or protocol (see sidebar for the definition of protocol) to send information back and forth. This problem was solved by the invention of Transmission Control Protocol/Internet Protocol (TCP/IP). TCP/IP was designed to allow networks running on different protocols to have an intermediary protocol that would allow them to communicate. So as long as your network supported TCP/IP, you could communicate with all of the other networks running TCP/IP. TCP/IP quickly became the standard protocol and allowed networks to communicate with each other. It is from this breakthrough that we first got the term Internet, which simply means “an interconnected network of networks.”


    Sidebar: An Internet Vocabulary Lesson

    Network communication is full of some very technical concepts based on simple principles. Learn the following terms and you’ll be able to hold your own in a conversation about the Internet.

    • Packet The fundamental unit of data transmitted over the Internet. When a host (PC, workstation, server, printer, etc.) intends to send a message to another host (for example, your PC sends a request to YouTube to open a video), it breaks the message down into smaller pieces, called packets. Each packet has the sender’s address, the destination address, a sequence number, and a piece of the overall message to be sent. Different packets in a single message can take a variety of routes to the destination and they can arrive at different times. For this reason the sequence number is used to reassemble the packets in the proper order at the destination.
    • Switch A network device that connects multiple hosts together and forwards packets based on their destination within the local network which is commonly known as a Local Area Network (LAN).
    • Router A device that receives and analyzes packets and then routes them towards their destination. In some cases a router will send a packet to another router. In other cases it will send it directly to its destination. Routers are used to connect one network to another network.
    • IP Address Every device on the Internet (personal computer, a tablet, a smartphone, etc.) is assigned a unique identifying number called an IP (Internet Protocol) address. Originally, the IPv4 (version 4) standard was used. It had a format of four numbers with values ranging from 0 and 255 separated by a period. For example, the domain Dell.com has the IPv4 address 107.23.196.166. The IPv4 standard has a limit of 4,294,967,296 possible addresses. As the use of the Internet has grown, the number of IP addresses needed has increased to the point where the use of IPv4 addresses will be exhausted. This has led to the new IPv6 standard.The IPv6 standard is formatted as eight groups of four hexadecimal digits, such as 2001:0db8:85a3:0042:1000:8a2e:0370:7334. The IPv6 standard has a limit of 3.4×1038 possible addresses. For example, the domain LinkedIn.com has an IPv6 address of: [2620:109:c002::6cae:a0a]. You probably noticed that the address has only five groups of numbers. That’s because IPv6 allows the use of two semi-colons ( :: ) to indicate groups that are all zeroes and do not need to be displayed. For more detail about the IPv6 standard, see this Wikipedia article.
    • Domain name If you had to try to remember the IP address of every web site you wanted to access, the Internet would not be nearly as easy to use. A domain name is a human-friendly name, convenient for remembering a website. These names generally consist of a descriptive word followed by a dot (period) and the Top-Level Domain (TLD). For example, Wikipedia’s domain name is wikipedia.org. Wikipedia describes the organization and .org is the TLD. Other well-known TLDs include .com, .net, and .gov. For a list and description of top level domain names, see this Wikipedia article.
    • DNS DNS stands for “domain name server or system.” DNS acts as the directory of websites on the Internet. When a request to access a host with a domain name is given, a DNS server is queried. It returns the IP address of the host requested, allowing for proper routing.
    • Packet-switching When a message’s packets are sent on the Internet, routers try to find the optimal route for each packet. This can result in packets being sent on different routes to their destination. After the packets arrive they are re-assembled into the original message for the recipient. For more details on packet-switching, see this interactive web page.
    • Protocol A protocol is the set of rules that govern how communications take place on a network. For example, File Transfer Protocol (FTP) are the communication rules for transferring files from one host to another. TCP/IP, discussed earlier, is known as a protocol suite since it contains numerous protocols.

    Internet Users Worldwide, December 2017.

    (Public Domain. Courtesy of the Miniwatts Marketing Group)

    The 1980s witnessed a significant growth in Internet usage. Internet access came primarily from government, academic, and research organizations. Much to the surprise of the engineers, the early popularity of the Internet was driven by the use of electronic mail (see the next sidebar ).

    Initially, Internet use meant having to type commands, even including IP addresses, in order to access a web server. That all changed in 1990 when Tim Berners-Lee introduced his World Wide Web project which provided an easy way to navigate the Internet through the use of hypertext. The World Wide Web gained even more steam in 1993 with the release of the Mosaic browser which allowed graphics and text to be combined as a way to present information and navigate the Internet.

    The Dot-Com Bubble

    In the 1980s and early 1990s, the Internet was being managed by the National Science Foundation (NSF). The NSF had restricted commercial ventures on the Internet, which meant that no one could buy or sell anything online. In 1991, the NSF transferred its role to three other organizations, thus getting the US government out of direct control over the Internet and essentially opening up commerce online.

    This new commercialization of the Internet led to what is now known as the dot-com bubble. A frenzy of investment in new dot-com companies took place in the late 1990s with new tech companies issuing Initial Public Offerings (IPO) and heating up the stock market. This investment bubble was driven by the fact that investors knew that online commerce would change everything. Unfortunately, many of these new companies had poor business models and anemic financial statements showing little or no profit. In 2000 and 2001, the bubble burst and many of these new companies went out of business. Some companies survived, including Amazon (started in 1994) and eBay (1995). After the dot-com bubble burst, a new reality became clear. In order to succeed online, e-business companies would need to develop business models appropriate for the online environment.

    Web 2.0

    In the first few years of the World Wide Web, creating and hosting a website required a specific set of knowledge. A person had to know how to set up a web server, get a domain name, create web pages in HTML, and troubleshoot various technical issues.

    Starting in the early 2000s, major changes came about in how the Internet was being used. These changes have come to be known as Web 2.0. Here are some key characteristics in Web 2.0.

    • Universal access to Apps
    • Value is found in content, not display software
    • Data can be easily shared
    • Distribution is bottom up, not top down
    • Employees and customers can use access and use tools on their own
    • Informal networking is encouraged since more contributors results in better content
    • Social tools encourage people to share information
      [1]

    Social networking, the last item in the list, has led to major changes in society. Prior to Web 2.0 major news outlets investigated and reported important news stories of the day. But in today’s world individuals are able to easily share their own views on various events. Apps such as Facebook, Twitter, Youtube, and personal blogs allow people to express their own viewpoint.


    Sidebar: E-mail Is the “Killer” App for the Internet

    As discussed in chapter 3, a “killer app” is a use of a device that becomes so essential that large numbers of people will buy the device just to run that application. The killer app for the personal computer was the spreadsheet, enabling users to enter data, write formulas, and easily make “what if” decisions. With the introduction of the Internet came another killer app – E-mail.

    The Internet was originally designed as a way for the Department of Defense to manage projects. However, the invention of electronic mail drove demand for the Internet. While this wasn’t what developers had in mind, it turned out that people connecting with people was the killer app for the Internet. As we look back today, we can see this being repeated again and again with new technologies that enable people to connect with each other.


    Sidebar: The Internet and the World Wide Web Are Not the Same Thing

    Many times the terms “Internet” and “World Wide Web,” or even just “the web,” are used interchangeably. But really, they are not the same thing.

    The Internet is an interconnected network of networks. Services such as email, voice and video, file transfer, and the World Wide Web all run across the Internet.The World Wide Web is simply one part of the Internet. It is made up of web servers that have HTML pages that are being viewed on devices with web browsers.


    The Growth of High Speed Internet

    In the early days of the Internet, most access was accomplished via a modem over an analog telephone line. A modem was connected to the incoming phone line when then connected to a computer. Speeds were measured in bits-per-second (bps), with speeds growing from 1200 bps to 56,000 bps over the years. Connection to the Internet via modems is called dial-up access. As the web became more interactive, dial-up hindered usage when users wanted to transfer more and more data. As a point of reference, downloading a typical 3.5 MB song would take 24 minutes at 1200 bps and 2 minutes at 28,800 bps.

    High speed Internet speeds, by definition, are a minimum of 256,000 bps, though most connections today are much faster, measured in millions of bits per second (megabits or Mbps) or even billions (gigabits). For the home user, a high speed connection is usually accomplished via the cable television lines or phone lines using a Digital Subscriber Line (DSL). Both cable and DSL have similar prices and speeds, though price and speed can vary in local communities. According to the website Recode, the average home broadband speed ranges from 12 Mbps and 125 Mbps.[2] Telecommunications companies provide T1 and T3 lines for greater bandwidth and reliability.

    High speed access, also known as broadband, is important because it impacts how the Internet is used. Communities with high speed Internet have found residences and businesses increase usage of digital resources. Access to high speed Internet is now considered a basic human right by the United Nations, as declared in their 2011 statement:

    “Broadband technologies are fundamentally transforming the way we live,” the Broadband Commission for Digital Development, set up in 2017 by the UN Educational Scientific and Cultural Organization (UNESCO) and the UN International Telecommunications Union (ITU), said in issuing “The Broadband Challenge” at a leadership summit in Geneva.

    “It is vital that no one be excluded from the new global knowledge societies we are building. We believe that communication is not just a human need – it is a right.”[3]

    Wireless Networking

    Thanks to wireless technology, access to the Internet is virtually everywhere, especially through a smartphone.

    Wi-Fi

    Wi-Fi takes an Internet signal and converts it into radio waves. These radio waves can be picked up within a radius of approximately 65 feet by devices with a wireless adapter. Several Wi-Fi specifications have been developed over the years, starting with 802.11b in 1999, followed by the 802.11g specification in 2003 and 802.11n in 2009. Each new specification improved the speed and range of Wi-Fi, allowing for more uses. One of the primary places where Wi-Fi is being used is in the home. Home users access Wi-Fi via in-home routers provided by the telecommunications firm that services the residence.

    Mobile Network

    As the cellphone has evolved into the smartphone, the desire for Internet access on these devices has led to data networks being included as part of the mobile phone network. While Internet connections were technically available earlier, it was really with the release of the 3G networks in 2001 (2002 in the US) that smartphones and other cellular devices could access data from the Internet. This new capability drove the market for new and more powerful smartphones, such as the iPhone, introduced in 2007. In 2011, wireless carriers began offering 4G data speeds, giving the cellular networks the same speeds that customers were accustomed to getting via their home connection.

    Beginning in 2019, some part of the world began seeing the implementation of 5G communication networks. Speeds associated with 5G will be greater than 1 GB/second, providing connection speeds to handle just about any type of application. Some have speculated that the 5G implementation will lead households to eliminate the purchase of wired Internet connections for their homes, just using 5G wireless connections instead.


    3G, 4G, and 5G Comparison
    3G 4G 5G
    Deployed 2004-2005 2006-2010 By 2020
    Bandwidth 2 mbps 200 mbps > 1 gbps,
    Service Integrated high-quality audio, video and data Dynamic information access, variable devices Dynamic information access, variable devices with all capabilities

    (James Dean, Raconteur, December 7, 2014)
    [4]


    Sidebar: Why Doesn’t My Cellphone Work When I Travel Abroad?

    As mobile phone technologies have evolved, providers in different countries have chosen different communication standards for their mobile phone networks. There are two competing standards in the US: GSM (used by AT&T and T-Mobile) and CDMA (used by the other major carriers). Each standard has its pros and cons, but the bottom line is that phones using one standard cannot easily switch to the other. This is not a big deal in the US because mobile networks exist to support both standards. But when traveling to other countries, you will find that most of them use GSM networks. The one exception is Japan which has standardized on CDMA. It is possible for a mobile phone using one type of network to switch to the other type of network by changing out the SIM card, which controls your access to the mobile network. However, this will not work in all cases. If you are traveling abroad, it is always best to consult with your mobile provider to determine the best way to access a mobile network.


    Bluetooth

    While Bluetooth is not generally used to connect a device to the Internet, it is an important wireless technology that has enabled many functionalities that are used every day. When created in 1994 by Ericsson, it was intended to replace wired connections between devices. Today, it is the standard method for wirelessly connecting nearby devices. Bluetooth has a range of approximately 300 feet and consumes very little power, making it an excellent choice for a variety of purposes. Some applications of Bluetooth include: connecting a printer to a personal computer, connecting a mobile phone and headset, connecting a wireless keyboard and mouse to a computer, or connecting your mobile phone to your car, resulting in hands free operation of your phone.

    VoIP

    Diagram of VoIP communication
    Typical VoIP communication

    Voice over IP (VoIP) allows analog signals to be converted to digital signals, then transmitted on a network. By using existing technologies and software, voice communication over the Internet is now available to anyone with a browser (think Skype, WebEx, Google Hangouts). Beyond this, many companies are now offering VoIP-based telephone service for business and home use.

    Organizational Networking

    LAN and WAN

    Scope of business networks

    While the Internet was evolving and creating a way for organizations to connect to each other and the world, another revolution was taking place inside organizations. The proliferation of personal computers led to the need to share resources such as printers, scanners, and data. Organizations solved this problem through the creation of local area networks (LANs), which allowed computers to connect to each other and to peripherals.

    A LAN is a local network, usually operating in the same building or on the same campus. A Wide Area Network (WAN) provides connectivity over a wider area such as an organization’s locations in different cities or states.

    Client-Server

    Client-server computing provides stand-alone devices such as personal computers, printers, and file servers to work together. The personal computer originally was used as a stand-alone computing device. A program was installed on the computer and then used to do word processing or calculations. With the advent of networking and local area networks, computers could work together to solve problems. Higher-end computers were installed as servers, and users on the local network could run applications and share information among departments and organizations.

    Intranet

    An intranet, as the name implies, provides web-based resources for the users within an organization. These web pages are not accessible to those outside the company. The pages typically contain information useful to employees such as policies and procedures. In an academic setting the intranet provides an interface to learning resources for students.

    Extranet

    Sometimes an organization wants to be able to collaborate with its customers or suppliers while at the same time maintaining the security of being inside its own network. In cases like this a company may want to create an extranet, which is a part of a company’s network that can be made available securely to those outside of the company. Extranets can be used to allow customers to log in and place orders, or for suppliers to check their customers’ inventory levels.

    Sometimes an organization will need to allow someone who is not located physically within its internal network to gain secure access to the intranet. This access can be provided by a virtual private network (VPN). VPNs will be discussed further in Chapter 6 which focuses on Information Security).


    Sidebar: Microsoft’s SharePoint Powers the Intranet

    As organizations begin to see the power of collaboration between their employees, they often look for solutions that will allow them to leverage their intranet to enable more collaboration. Since most companies use Microsoft products for much of their computing, some are using Microsoft’s SharePoint to support employee collaboration.

    SharePoint provides a communication and collaboration platform that integrates seamlessly with Microsoft’s Office suite of applications. Using SharePoint, employees can share a document and edit it together, avoiding the need to email the document for others to review. Projects and documents can be managed collaboratively across the organization. Corporate documents are indexed and made available for search.


    Cloud Computing

    Cloud computing was covered in Chapter 3. The universal availability of the Internet combined with increases in processing power and data-storage capacity have made cloud computing a viable option for many companies. Using cloud computing, companies or individuals can contract to store data on storage devices somewhere on the Internet. Applications can be “rented” as needed, giving a company the ability to quickly deploy new applications. The I.T. department benefits from not having to maintain software that is provided on the cloud.


    Sidebar: Metcalfe’s Law

    Just as Moore’s Law describes how computing power is increasing over time, Metcalfe’s Law describes the power of networking. Metcalfe’s Law states that the value of a telecommunications network is proportional to the square of the number of connected users of the system, or N2. If a network has 10 nodes, the inherent value is 100, or 102.

    Metcalfe’s Law is attributed to Robert Metcalfe, the co-inventor of Ethernet. It attempts to address the added value provided by each node on the network. Think about it this way: If none of your friends were on Instagram, would you spend much time there? If no one else at your school or place of work had e-mail, would it be very useful to you? Metcalfe’s Law tries to quantify this value.


    Summary

    The networking revolution has completely changed how personal computers are used. Today, no one would imagine using a computer that was not connected to one or more networks. The development of the Internet and World Wide Web, combined with wireless access, has made information available at our fingertips. The Web 2.0 revolution has made everyone potential authors of web content. As networking technology has matured, the use of Internet technologies has become a standard for every type of organization. The use of intranets and extranets has allowed organizations to deploy functionality to employees and business partners alike, increasing efficiencies and improving communications. Cloud computing has truly made information available everywhere.


    Study Questions

    1. What were the first four locations hooked up to the Internet (ARPANET)?
    2. What does the term packet mean?
    3. Which came first, the Internet or the World Wide Web?
    4. What was revolutionary about Web 2.0?
    5. What was the so-called killer app for the Internet?
    6. What does the term VoIP mean?
    7. What is a LAN?
    8. What is the difference between an intranet and an extranet?
    9. What is Metcalfe’s Law?

    Exercises

    1. What is the difference between the Internet and the World Wide Web? Create at least three statements that identify the differences between the two.
    2. Who are the broadband providers in your area? What are the prices and speeds offered?
    3. Pretend you are planning a trip to three foreign countries in the next month. Consult your wireless carrier to determine if your mobile phone would work properly in those countries. What would the costs be? What alternatives do you have if it would not work?

    Labs

    1. Check the speed of your Internet connection by going to the following web site: speedtest.net
      What is your download and upload speed?
    2. What is the IP address of your computer? How did you find it? Hint for Windows: Go to the start icon and click Run. Then open the Command Line Interface by typing: cmd Then type: ipconfigWhat is your IPv4 address?What is your IPv6 address?
    3. When you enter an address in your web browser, a Domain Name Server (DNS) is used to lookup the IP address of the site you are seeking. To locate the DNS server your computer is using, type: nslookupWrite down the name and address of your DNS server.Use the nslookup command to find the address for a favorite web site. For example, to find the IP address of espn type: nslookup espnWrite down your website’s name and address. Note: it is on the line following the name of the web site you entered.
    4. You can use the tracert (trace route) command to display the path from your computer to the web site’s IP address you used in the previous lab. For example, tracert 199.181.132.250Be patient as tracert contacts each router in the path to your website’s server. A “Request timed out” message indicates the tracing is taking too long, probably due to a lack of bandwidth. You can stop the trace by pressing Ctrl + C
    5. The ping command allows you check connectivity between the local host (your computer) and another host. If you are unable to connect to another host, the ping command can be used to incrementally test your connectivity. The IP address 127.0.0.1 is known as your home address (local host).Begin your test by going to your command line interface (command promkpt) and pinging your local host: ping 127.0.0.1You should get a series of “Reply from 127.0.0.1” messagesNext, ping the IP address you used in lab #3.Sometimes a failed ping is not the result of a lack of connectivity. Network administrators of some IP addresses/hosts do not want their site pinged so they block all ICMP packets. That’s the protocol used for pinging.
    • The whois.domaintools.com site provides you with information about a web site. For example, to find information about google.com open your web browser and type: whoisdomaintools.com Then in the Lookup window, type: google.comFind information about a favorite site of yours. Record the following: administrator name, phone number, when the site was created, and the site’s name servers (the names begin with “ns”).
    • Network statistics can be displayed using the netstat command. In the command line window (see lab #2 for instructions on how to get to the command line), type: netstat -eHow many bytes were sent and how many were received?Execute the command again and record your results. You should see an increase in both received and sent bytes.To see a complete list of options/switches for the netstat command, type: netstat ?

    1. Wolcott, M. (2017). What is Web 2.0? MoneyWatch. Retrieved from https://www.cbsnews.com/news/what-is-web-20/
    2. Molla, R. (2017). These are the fastest and slowest Internet speeds”. Recode. Retrieved from https://www.recode.net/2017/6/9/1576...nternet-speeds
    3. International Telecommunications Union. (2018, January 23). UN Broadband Commission sets goal broadband targets to bring online the world’s 3.8 billion not connected to the Internet. Retrieved from https://www.itu.int/en/mediacentre/P...2018-PR01.aspx
    4. “Dean, J. (2014). 4G vs 5G Mobile Technology. Raconteur Retrieved from https://www.raconteur.net/technology...ile-technology.