Introduction to Computer Information Systems/Computer Networks

From Wikibooks, open books for an open world
Jump to: navigation, search

Networking Applications[edit]

GPS Satellite NASA art-iif.crop

There are many different types of network applications. First and foremost is the internet, the largest network of networks in the world. Second, there are our phones, the oldest of which is POTS (plain old telephone service), which one day could be replaced by the newer technology, mobile phones. Mobile phones have been around for a few years now, and are beginning to replace home phone lines. Mobile phones can be separated into two groups, cellular phones and satellite phones. Cell phones work by communicating with cell towers in order to function. There are some dual mode phones which allow you to make phone calls through a WIFI signal, and switch to cell signal when out of WIFI range. Satellite phones work by communicating with satellites in space, this is primarily used with the military, where cell tower coverage is nearly impossible in some locations. While satellite phones can be used in rural and mountainous arias, the drawback to them is when there is a storm or heavy clouds, you can lose your signal. Satellites are also used with a GPS[1](global positioning system). GPS functions by relaying data between your device and the 24 satellites in space. They work similarly to sonar waves. The signal leaves the satellite, and depending on how long it takes to get to you will determine your exact location.

RFID chip

Monitoring Systems are another form of networking applications. These systems specialize in locating a specific person, vehicle or device rather than pulling up geographical information like a GPS does. However, most monitoring systems use GPS in locating their targets. Radio Frequency Identification (or RFID) for example, can be used to locate a person or animal with an RFID chip embedded inside of it. Most commonly recognized for it's ability track pets that have the chip implanted, RFID has also moved into the human medical field. In fact, some breast implants in the United Kingdom have been chipped so that a physician can read information about the implant years after the surgery has been completed.[2] While this is the social reasoning for this type of chipping, it seems that medical records housed on inexpensive servers would suit this purpose just fine. The fact remains that RFID chips, which are about the size of a grain of rice, operate using a small silicon chip and a copper antenna which emit personal information about it's owner. This information is then picked up by electronic networks feeding back information about the product, the person carrying it, and it's location to the network. It's currently being used to track cattle and Alzheimer's patients as well as merchandise produced by manufacturers.[3]. Other monitoring systems include vehicle tracking software such as the famous OnStar. This type of networking application has been expanded so that employers can spy on employees using company vehicles. With a simple installation, the latest vehicle tracking applications can feed information about the geographic location of a company vehicle, the speed of the vehicle, and even "hard breaking" events. Mobile phones aren't omitted either. Since most of the current mobile phones have stand alone GPS systems a person can track the movements of the individuals under their plan as well as their own phone if it is stolen.[4]

Multimedia networking has exploded as well. This type of networking offers digital multimedia content such as movies, music, and recorded t.v. shows to be viewed over a phone, p.c., or television. While most devices already have the required capabilities built in, some devices need may need a receiver. Placeshifting is common with this type of network which will allow an individual to download content from one place and view it in another, i.e. from a t.v. to a mobile phone. Similarly, VideoConferencing allows people to interact remotely from separate locations. Instead of streaming a movie in real time, a person can stream a video feed from a relative or business part who might be across the globe. They can then interact and speak as they normally would while viewing the mannerisms of others in real time. Also, through the use of videoconferencing Telemedicine has been used to diagnose and treat patients who are unable to access a doctor in person because of their poverty level, geographical area, or physical condition. Physicians, with the assistance of a member on site with the patient, use videoconferencing to conduct tests such as simple ear and throat checkups to procedures as complex as actual surgery in some cases.[5]

Network Characteristics[edit]

Network Architecture & Network Topologies[edit]

Bus Topology


Network architecture is the layout of the network. The hardware, software, communication protocols, and mode of transmission consists in the network architecture. The network architecture plays an essential role in today's society; therefore, one should be aware of the network architecture, and the different types of network topologies as well. [6] Network topology is how different nodes in a network are connected to each other and how they communicate. The five most common topologies are mesh topology, star topology, bus topology, ring topology, and tree topology. In a mesh topology, devices are connected with many excessive interconnections between network mode. In a star topology, the devices are connected to a central computer, and the nodes communicate across the network by passing data through the hub, which is the central computer. In a bus topology, it connects all devices on a local-are network called LAN. Bus networks are not very pricey, and they are easy to install. In a ring topology, it consists of a local area network whose topology is a ring. The messages travel around the ring. In a tree topology, it is considered a "hybrid" topology that combines characteristics of the bus and star topologies.[7]

Data Transmission Characteristics[edit]

Bandwidth[edit]

Bandwidth.svg

Bandwidth is the amount of data that can be transmitted in a certain amount of time. Bandwidth is also referred to as throughput. The most common measure of bandwidth is bits per second (bps), but it is also measures in Kbps, which is thousands of bits per second; Mbps, which is millions of bits per second; or Gbps, which is billions of bits per second. [8] Bandwidth is the capacity of the connection. A network medium with a higher bandwidth will allow more data to pass through in a certain amount of time. So the greater the capacity, the better the performance will be. This isn’t always true though because performance depends on other things too. Text data requires the least amount least amount of bandwidth and video data requires the most. [9]

Analog vs. Digital Signals[edit]

The red is a digital signal and the gray would be an analog signal

Analog signal is a continuous signal. It has constant fluctuations. A digital signal is an electrical signal that is converted into a pattern of bits. It has a discrete value at each sampling point. [10] Each sample is defined with a series of bits that are either 0s or 1s. Analog signals are denoted by sine waves whereas digital signal is square waves. Analog signals would be things like human voices in the air and analog electronic devices. Digital signals are for things like computers, CDs, DVDs, and other digital electronic devices. The advantages of digital signal are that the recording does not degrade over time and groups of numbers can often be compressed by finding patterns in them. [11]

Transmission Type and Timing[edit]

Network Data Transfer

For the transfer of data and networking media, there can be two ways to send information. Serial transmission is data sent in a single path, one bit at a time [12]. An example of this would be a classroom of students lining up single file at the door and exiting one by one. Parallel transmission is data sent one byte at a time, but each bit in the byte takes a separate route [13]. This is a more efficient way of sending or receiving data. For instance, parallel transmission can be identified as students walking through a large hallway in a school to get to their specific classrooms. This way, there is more space involved, in order for the data to be received more efficiently. However, most networking media usually use serial transmission.

Synchronous, Asynchronous, and isochronous transmission are three different ways that serial transmission is transferred. Synchronous transmission is ordered into groups and blocks of data that are transferred one after the other. Asynchronous transmission is not used as much as synchronous because it is sent when it is ready. The data is not synchronized which makes the end result less efficient. Isochronous transmission sends the data all at once. [14]

Data can also travel in mainly three distinct ways. Simplex transmission is when the data is traveling in only one direction. Half-duplex transmission sends the data in either direction, but data can be sent only in one direction at a time. Full-duplex transmission sends the data back and forth in either direction and can be simultaneous.


Delivery Method[edit]

Data is delivered by using circuit switching, which is a specific path between a sender and a receiver. A telephone system is an example of circuit switching because the path is dedicated to only those two people for the time being. Once they are off the phone, the path is free to use by whomever else. Sending data over the Internet is called packet switching. The messages sent are detached in “packets.” While traveling through the Internet, the packets contain all information going from the sender to the receiver. Once the transmission is complete, the packets are put back together to create the correct message.

Communications Protocols and Networking Standards[edit]

The definition and usage of TCP/IP[edit]

This is a visual representation of how all the IP addresses are connected to each other

There's little argument that the most popular communications protocol being used today is TCP/IP. The protocol that's used for transferring data over the Internet, TCP/IP is actually a combination of two protocols. The TCP part of the equation stands for Transmission Control Protocol and it is culpable for data delivery. IP stands for Internet Protocol and it provides routing information and addresses. There are several reasons for the continued popularity of TCP/IP. One of these reasons is the flexibility of the dual protocols, as the core has been able to remain largely the same over 25 years, even with the immense growth of internet popularity. Another reason is the routing design, as TCP/IP is designed specifically to facilitate the routing of information over a network of arbitrary complexity.[15] Pretty much all operating systems have built in support for the TCP/IP protocols so that is also a big factor in their popularity.


One potential controversy related to IP's in particular was the scare when the Internet had run out of Internet addresses. The original IP version, called IPv4, had used up all the potential number combinations so no new folks would have been able to connect to the internet... that is, until IPv6 came out. It uses 128 bit addresses, versus the mere 32 bits of IPv4, ensuring that it will be another long time to go until we risk running out of internet addresses again.[16]

Cellular Standards[edit]

4th Generation Technology

It is no secret that the technology used for mobile phones has vastly evolved over the years. What started out as basically a mobile brick has quickly transformed into a compact, highly productive, and speedy cellular communication device. However, many people are unaware of the generational breakdown of these devices. When the first generation mobile phone was released decades ago in the 1980s, it was produced with only the purpose of voice communication in mind. It was not until the second generation came out years later, around the 1990s, that we started to see both data and voice combined into one device. This generation is best known for its access to both Global System for Mobile communications (GSM) and Code Division Multiple Access (CDMA) which greatly work to enhance speed and communication up to 14.4 Kbps. When the third generation came along in the 2000s, we saw companies start to use packet switching and access speeds as fast as 2 Mbps. This brings us to where we are today. Cellular companies across the globe are starting to utilize 4g technology and offer outstanding speeds of up to 20 Mbps. With technology constantly evolving and expanding, where will it take us next? Into what technological wonders is fifth generation technology going to bring us? [17]

Wireless Printers[edit]

A common printer

Wi-Fi is one of the most popular networking standards that uses wireless LANs. Certain devices come Wi-Fi enabled and some can be hooked up within the wireless network. One of the most popular devices being used today is the wireless printer. Not any printer can be used, however. Special printers nowadays have the Wi-Fi transceivers built into them to locate the available networks. The major advantage is that multiple computers can print to a printer in any location that you want. Another great advantage is that you can avoid the painful cable clutter that comes with all of the devices you could hook up to the computer. It takes much less time for a computer to connect to the printer through Wi-Fi then it does to download the software and connect it manually with a USB cord. One thing to consider though is how windows and doors might affect the strength of the signal. Security is something to think about as well. Some printers contain a WPA (Wi-Fi Protected Access) encryption that allows only special computers to connect if they activate the similar feature. [18]Believe it or not, these types of printers are actually reasonably priced compared to some of the other types of electronics out there on the market.

Networking Hardware[edit]

Network Adapter preferences

Network adapters are used to connect a computer to a high-speed network. If it’s the home computer that you are installing a networks adapter than you will want to install a NIC if it isn’t already built into the mobo. The high quality networks cards are cheap enough that you won’t want to drive to get one from a store. A lot of mobos have them already built in, but any NIC will come with all recent windows Verizon, and if not using that provider than make sure it will function with the OS you plan to utilize.


Modems are able to convert your computers digital data to analog data that can be sent over telephone service lines and converts incoming analog data to digital data that the computer can work with. An internet PCI modem are cheap as well and can be found around 5 dollars, but it’s not beneficial to buy the cheaper modem because of the way they process instead of the normal way. The better quality modems are provided a device that is able to do the work directly on the card. They are known to be faster and more efficient than a cheaper modem, go figure![19]

Hardware for Connecting Devices and Networks[edit]

A wireless router

There are different configurations used in connecting devices to a network as well as connecting networks to other networks. An example of a configuration for a home network is a star topology where there is one central device that provides a connection for other devices. This central device, or hub, is not as efficient regarding the availability of bandwidth between the devices, specifically computers, that are connected to the hub. More exactly, the hub can lead to unnecessary traffic build-up because it repeats everything it receives to other devices. This may or may not be an issue depending on the size of the network. A small network will not have much issue with using a hub for a central device, but for other, larger networks a different device may be more practical. A switch is more suitable for larger networks. Like hubs, switches allow devices to communicate with each other. However switches contain ports that are designated for individual devices, which allows for a more efficient allocation of bandwidth for the devices as a whole.[20]

Routers are used to connect multiple networks by taking information from broadband signals, through a modem, and then sending it to each network.[21] Because they maintain configuration information in a storage known as a routing table, routers can filter incoming or outgoing traffic.[22] Wireless access points are devices that allow a device access to the network. This, along with a switch, can be found in wireless routers. These routers connect both wired and wireless devices to a network, which then connects that network to the Internet. Another device is a bridge, which simply connects two LANs. An example of this would be connecting a game console to a home network.


Review[edit]

Review Definitions[edit]

Analog signal: A type of signal where the data is represented by continuous waves.

Bluetooth: A networking standard for very short-range wireless connections; the devices are automatically connected once they get within the allowable range.

Bus Network: A network consisting of a central cable to which all network devices are attached.

Coaxial Cable: A networking cable consisting of a center wire inside a grounded, cylindrical shield, capable of sending data at high speeds.

Ethernet (802.3): A widely used wired LAN networking standard.

Extranet: An intranet that is at least partially accessible to authorized outsiders.

Fiber-Optic Cable: A networking cable that utilizes hundreds of thin transparent fibers over which lasers transmit data as light.

Intranet: A private network that is set up similar to the Internet and is accessed via a Web browser.

Local Area Network (LAN): A network that connects devices located in a small geographical area, such as within a building.

Mesh Network: A network in which there are multiple connections between the devices on the network so that messages can take any of several possible paths.

Modem: A device that enables a computer to communicate over analog networking media, such as connecting to the Internet via telephone lines.

Parallel Transmission: A type of data transmission in which bytes of data are transmitted at one time, with the bits in each byte taking a separate path.

Router: A device that connects multiple networks together; routes packets to their next location in order to efficiently reach their destination.

Serial Transmission: A type of data transmission in which the bits in a byte travel down the same path one after the other.

Virtual Private Network (VPN): A private, secure path over the Internet that provides authorized users a secure means of accessing a private network via the Internet.

Wireless Network: A network in which computers and other devices are connected to the network without physical cables; data is typically sent via radio waves.

Review Questions[edit]

1.) Third generation computers became smaller and more reliable than earlier computer generations, incorporating multiple transistors and electronic circuits on a singles tiny silicon chip by utilizing ______________.

2.) A small business needs a computer that can act as a server for a number of PCs and handle a number of users running different applications. The class of computer best suited to its needs would be a(n) __________

3.) Programs designed to perform specific tasks or applications, such as computing bank-account interest, preparing bills, or creating letters, are contained in ____________

4.) An example of system software is __________________

5.) PC-compatible and Mac are the two major personal computer ____________

6.) The purpose of a computer network is to allow computers to _____________

7.) Computers and the traditional devices that we use every day- such as the telephone, TV, and home entertainment system- have begun to merge into single units with multiple capabilities; this trend is referred to as ____________

8.) Having a basic understanding of computers and their uses is called _______________

9.) The four main computer operations are input, output, storage, and _________

10.) A mobile device based on a mobile phone that can be used to access the Web and e-mail wirelessly, as well as other capabilities such as taking digital photos, is often referred to as a(n) ___________

Review Answers[edit]

Answers 1.) Integrated Circuits 2.) Midrange Server 3.) Application Software 4.) Windows 5.) Platforms 6.) Communicate with each other, share software, and share hardware 7.) Convergence 8.) Computer Literacy 9.) Processing 10.) Smartphone [23]

  1. wiki: Global_Positioning_System
  2. http://www.rfidjournal.com/articles/view?11093
  3. http://electronics.howstuffworks.com/gadgets/high-tech-gadgets/rfid.htm
  4. http://www.caranddriver.com/features/vehicle-tracking-systems-and-data-recorders-tested-gearbox
  5. http://www.americantelemed.org/learn
  6. http://en.kioskea.net/faq/2761-what-is-network-architecture
  7. http://www.webopedia.com/DidYouKnow/Hardware_Software/Networking/tree_topology.html
  8. http://searchenterprisewan.techtarget.com/definition/bandwidth
  9. http://compnetworking.about.com/od/speedtests/g/bldef_bandwidth.htm
  10. http://www.ask.com/question/what-is-the-difference-between-analog-and-digital-signals
  11. http://www.diffen.com/difference/Analog_vs_Digital
  12. http://en.wikipedia.org/wiki/Serial_communication
  13. http://en.wikipedia.org/wiki/Parallel_communication
  14. http://en.wikipedia.org/wiki/Comparison_of_synchronous_and_asynchronous_signalling
  15. http://www.tcpipguide.com/free/t_TCPIPOverviewandHistory-3.htm
  16. http://mashable.com/2011/02/03/ipv4-ipv6-guide/
  17. http://bpastudio.csudh.edu/fac/lpress/471/hout/3G.htm
  18. http://www.hp.com/global/us/en/wireless/wireless-basics.html
  19. http://www.kitchentablecomputers.com/nic.php
  20. http://www.darron.net/network/secondpage.html
  21. http://whatismyipaddress.com/routers
  22. http://compnetworking.about.com/cs/routers/g/bldef_router.htm
  23. http://coursemate.cengage.com/CPReader/View/9781133114598/default.aspx?eISBN=9781133114598#da32b353-ffd5-4a88-91a8-c28f124d2211