Incorporate Internet Domain Survey, Lessons for the Future Internet (local copy),
ADD:  Malware and Network security  and peer-to-peer networks,
INCORPORATE into preassessment 1 and Proficiency Evaluation 1.

LAST UPDATE: 9/13/06; 2/9/07
Constantly being Updated!

OVERVIEW OF CYBERSPACE

   This learning module is a preview of the concepts associated with cyberspace in general and the Internet in particular. It is a superficial preview of material that will be covered in more detail in subsequent learning modules of this course. If you are an independent learner (not enrolled in the on-campus course), consult the Study Guide for this learning module before continuing.  In any case, if you haven't already done so, read the home page of the Study Guide.

The Objectives of this learning module are:

1. To survey the fundamentals of computer hardware and software necessary to understand Internet facilities; these are covered in the course COSC100.
2. To introduce the fundamental concepts of networking, in general, and the Internet, in paricular.  This includes:
1. the most popular Internet services that will be covered in more detail later in the course.
2. a summary of other network concepts that will not be covered further during this course.
3. To introduce the format of the online learning material.
4. To illustrate the techniques for studying this online, independent learning course.

TPQ OC.1: Rewrite the preceding objectives in terms of personal accomplishments to be attained after finishing the study of this learning module.(Note that this will be a standard exercise at the beginning of each learning module that is very important in order to "get you focused".For a hint, and link to Tony's answer, click on the link "Hints, TPQs" in the "Navigation Panel" along the left boarder of this Web page; this will be a standard facility throughout the course)

The sequence of presentations in this learning module is as follows.  You can click on any link to jump directly to that section.

1. CONCEPTS (summary of the COSC 100  INTRODUCTION TO COMPUTER SCIENCE content relevant to COSC 120.)
• 1.1  Computer Concepts
• 1.2  Data Processing Concepts
• 1.3  Hardware Concepts
• 1.4  Software Concepts
• 1.5  Network Concepts
2. THE INTERNET
• 2.1  The Internet is a Wide Area Network (WAN)
• 2.2  The Internet Provides a Wide Variety of Services
3. NETWORKS OTHER THAN THE INTERNET
   
4. NETWORK SECURITY AND PROTECTION AGAINST MALWARE 
   
5. SUMMARY OF THIS LEARNING MODULE

The Internet (often simply called "The Net".) is, by far, the dominant network of cyberspace and, thus, is the main focus of this course. It began as a way to communicate text-based data (e-mail, text documents, etc.) and programs (binary files sometimes called executable files), but has dramatically evolved especially with the development, within the Internet, of the World Wide Web (also called WWW, W3, or simply "The Web"), during the 90's. Today one can communicate via multimedia in video conferences or even enter mutual "virtual worlds" where the multiple users interact in an environment that exists only in a computer's memory. These virtual worlds can be anything the creator can imagine! Such facilities are provided by the Web, a subset of the Internet, that is the prototype of the cyberspace of the future.  Figure OOC-1 is a bit "dated", but I have found nothing better with which to replace it.  (If any reader does, let me know!)  The basic ideas of the schematic are still true today, but their relative importance and some specifics have changed dramatically.  If I were to draw a new version of the illustration of the current cyberspace, I would replace "matrix" with "cyberspace", reduce the size of Finger space, Gopher space, WAIS, Fidonet, UUCP, and BITNET to very small "blips"; then I would expand Web space to fill up the space vacated by the others.  Email space, FTP, and Telnet I would leave alone.  I would  add blobs for chat and teleconferencing.

The following presentation is a preview of the material to be covered in this course. It consists of (1) a review/preview of the basic computer concepts used to describe the Internet (section 1), a summary of the Internet components (section 2), other cyberspace constituents (sections 3-6), and a survey of other teleconferencing facilities. All of this material is concisely presented here to facilitate discussion, but all will be covered in more detail later. Therefore, do not become frustrated if you do not feel you understand this Learning Module as you read it, and try not to be discouraged with "information overload"! NOTE: You should refer back to this Overview when studying later details to see how they fit into the overall context of cyberspace.

1. CONCEPTS (Summary of COSC100 Content Relevant to COSC120):

     The following basic computer concepts are essential to the discussion of cyberspace. They are covered in detail in courses like COSC 100, Introduction to Computer Science (You can access my online version of this course by clicking here.You should do this in a separate window; otherwise you will get two navigation panels on the page!).  They can also be learned by outside reading or looking them up on the World Wide Web (e.g. click on the links to  Webopaedia, Computer Desktop Encyclopedia, Whatis, or FOLDOC in the Navigation Panel to the left.  Click here #4 and read comment #4.).

SAQ OC.1: To see what they are like, look up the definition of "Cyberspace" in each of the four on-line refernces? For a hint, and link to Tony's answer, click on the link "Hints, SAQs" in the "Navigation Panel" along the left boarder of this Web page; this will be a standard facility throughout the course)

1.1 Computer Concepts:

1. Computer = __________(1) (For a hint, and link to Tony's answer, click on the link "Hints, FIBs" in the "Navigation Panel" along the left boarder of this Web page; this will be a standard facility throughout the course) electronic machine that (a) processes digital data into information (numeric, text, or multimedia) (b) controls electrical devices.
2. Microcomputer = computer based on a __________(2) a "processor on a chip".
3. Computer System = people, hardware, software, data, and procedures.
4. Hardware = physical equipment of a computer system.
5. Software = __________(3) that "run" the computer.
6. Program = set of step-by-step instructions, in a _________ __________(4), that causes a computer to execute a specific task in finite time.

TPQ OC.2: What is the difference between a calculator and a computer?(For a hint, and link to Tony's answer, click on the link "Hints, TPQs" in the "Navigation Panel" along the left boarder of this Web page; this will be a standard facility throughout the course)

STUDY GUIDE NOTES:

1. SAQs (Self Assessment Questions) and TPQs (Thought Provoking Questions) are learning aids that will be used throughout my notes. Both types of questions are designed to help you focus on the essential characteristics of fundamental concepts. SAQs act as "traffic lights"; if you can't answer one, it is a symptom of a misunderstanding and you should review the notes to correct it. TPQs may have more than one correct answer; they may not even have any correct answer; they are simply there to make you think! You are strongly urged to think up your own SAQs and TPQs, using these as guides.  (The "Cyber Jeopardy" exercise in the PREASSESSMENTS  formalize this exercise by asking you to think up questions for each of the multiple choice answers.)  Searching your mind for such questions helps you to identify important concepts and think about them; thought is essential to obtaining understanding!
2. You should work continuously on the PREASSESSMENT associated with each learning module as you study.  PREASSESSMENT 120-1 is associated with learning modules I and II; you should read questions 1-20 because the answers to those questions are in this learning module I.  For now, answer the questions by circling the answers, then, when you have to submit the PREASSESSMENT you can easily transfer your answers to the scantron form that will be provided the day before the preassessment is due.
3. The blanks in the text, like the SAQs TPQs are learning aids. As such, the answers for them should NOT be written in the blanks; that simply turns the learning aids back into normal text (you are a spectator). Instead, if you feel you must write the answer down, place it in the margin or at the end of the chapter; then when reviewing the FIBs (Fill in the Blanks), SAQs and TPQs will make you think. (You become a PARTICIPANT instead of simply a spectator.)

The following flowchart representation, FIGURE 00C-2, can be used to illustrate virtually any computing function!  In this section this representation is used to visualize the conceptual operations involved in data processing. (See #6)  In Figure OOC-3 this same schematic format is used to relate different parts of computer hardware.

1. The schematic shows that information is processed __________(5), (facts, values, etc. organized for computer consumption); information is presented for __________(6) consumption.
1. Direct input includes data as well as the programs that process the data (in word processing the data would be text and the program would be the wordproessor) which are typically input from a keyboard, mouse, or some other direct input device.  In order to be processed the input must be encoded, i.e. translated from human language into machine (computer) language; this is done transparently (unseen by the user) as the input is read by the computer.
2. Local output goes directly to the user, typically via the computer monitor, speakers, printer, etc. and involves decoding from machine language back into human readable form.
3. Before being output to the user, processing may have intermediate output and return input involving disk storage or  communications.
1. Store operations save output to a data file, e.g. a text file from a word processor or an HTML file from a Web browser.
2. Communicate operations involve interactions with other computers; this is called "remote" input/output to distinguish it from "local" input/output.  Communications usually involves network transmissions, typically via the Internet. Unfortunately, many introductory texts still ignore the communicate activity (and miss the nice symmetry of the I-P-O schematic), so if you memorized a PC-centric version of this schematic you missed out on the fact that "the computer is the network" (Sun Microsystem's moto); be sure to remember the COMMUNICATE component and the nice balance of this schematic!
2. Virtually all computers are digital, i.e. they can only process digital data (discrete electronic signals). Digital data is stored in memory as collections of electronic switches (transistors) either being on or off; these primitive data elements are called bits (binary digits) and are represented by humans as 1 or 0; a collection of eight bits is called one byte which are used to represent single alphanumeric characters.
3. Computer data can have various forms including numeric (integer or "real"), text, and multimedia (audio, visual, etc.), but they are all digital and thus represented by precise collections of bits.
4. Most "real world" data is analog (continuous rather than discrete); therefore, it must be converted to digital (A/D conversion) when encoded and visa versa (D/A conversion) when being decoded. (For the distinction between analog and "digital" data see section 1.C in Learning Module 2, REVIEW/OVERVIEW OF COMMUNICATIONS AND NETWORKING; however, this distinction is not critical to the following discussion.)
5. Data and programs are stored (i.e. "saved") in files located in secondary storage. (Seesection 1.3.C, below.)
1. Data files digital data that is the "raw material" for the computer programs contained in executable files.  Examples include numeric data stored as binary numbers, text stored as binary codes, etc.
2. Executable files contain the programs that manipulate the data in data files. Executable files contain machine languages instructions (in a binary format) that can be executed, without translation, by the computer.
6. In order to complete a processing task, a computer might need to use data or run programs on other computers. This can be accomplished by communication via networks to which the client or server may not even be physically connected. (See section 1.5, below.)

1.3 Hardware Concepts:

     The following is a greatly oversimplified survey of the concepts associated with the interactions of the CPU with its peripheral devices.  It is intended only to familiarize the beginner with basic hardware terms needed to talk about computers used in telecommunications.  It is equivalent to the OVERVIEW OF COMPUTERS, part of my on-line course COSC 100, INTRODUCTION TO COMPUTERS; for a more detailed treatment see CENTRAL PROCESSING UNIT & PRIMARY MEMORY and INPUT/OUTPUT HARDWARE learning modules of that same course.

1. Computer Classifications:
1. An simplistic classification of computers can be made according to whether they are utilized by individuals or multiple users.
1. Personal computers (PCs) are designed for the single user, and are the most common means of Internet access; in such cases they are called "clients" (See below.)  PC's are microcomputers (computers based on a single CPU) which have subclassifications like desktops, portables, notebooks, etc.
2. Multi-user computers can be loosely categorized, according to decreasing power and price, under the following types: supercomputers, mainframes, and minicomputers.  Mainframes and minicomputers are used as Internet nodes where they route communications traffic.  They are also used as Internet servers in which case they provide a "service" (See below.) like a Web site; however current, powerful microcomputers can also act as servers.
2. In this course it is unnecessary to fully understand the distinctions between computer types, so further discussion of this topic is omitted.  As far as this course is concerned, it is only necessary to realize that users typically access cyberspace via microcomputers and that mainframes and and minicomputers are typically used as Internet nodes.
2. Generic Organization of the CPU and Peripheral Devices:

FIGURE OOC-3





1. The arrows within the CPU schematic above simply dramatize the complex interaction of the two conceptual components of the CPU (Control Unit (CU), and Arithmetic/Logic Unit (ALU)) and primary memory; this schematic really reflects the organization of a microcomputer, but is less true of large, multi-user computers like minicomputers and mainframes.WARNING: There is a discrepancy in the way different people define the CPU; some texts include primary memory as part of the CPU (I believe this is the most accurate description, but few introductory courses, which focus on microcomputers, use this terminology; therefore, I conform to the most "popular" definition.)
1. The ALU is a conceptual representation of the microchip circuits that (1) perform all the arithmetic calculations and (2) makes the computer equivalent of logic decisions.  One could characterize it as the "worker" of the CPU
2. The CU is a conceptual representation of the microchip circuits that governs the operation of the CPU, i.e. it is the "boss" of the CPU, telling the ALU what to do when.
3. Primary memory consists of RAM (random access memory which is read/write) and ROM (read only memory).  RAM is where the users programs (and their data) must be stored in order to be run.
2. Input, output, communications, and secondary storage equipment are called peripheral devices.  These may be on-line (directly connected to the CPU) or off-line (often called auxiliary devices).
1. Direct I/O hardware allows the user to interact directly with the computer; this distinguishes it from Indirect I/O described in the next section. Direct input hardware includes keyboards, pointing devices, etc., and direct output hardware includes monitors, printers, speakers, etc.  Direct I/O devices are more or less self explanatory and are really not very relevant to this course; therefore, they will not be discussed further.  For those interested, access my INPUT/OUTPUT HARDWARE learning module which is part of the COSC 100, Introduction to Computer Science, course.
2. Indirect I/O involves multiple outputs and inputs from devices connected to a computer before the final output goes to the user.  This has two basic subcategories. Secondary storage, which is not very relevant to this course, is briefly surveyed in the next section, and communications hardware, which is essential to this course, has a whole learning module, REVIEW/OVERVIEW OF COMMUNICATIONS AND NETWORKING, devoted to it; a few basic concepts are covered in section 1.3.D and section 1.5, below.
3. *Secondary Storage is currently dominated by magnetic media (hard disks, removable hard disks, and floppies), but magneto-optical and read/write optical media (DVD, DVD-RAM, and DVD+RW) promise to revolutionize storage technologies.
1. Magnetic media, old fashioned but constantly being improved, includes:
1. Floppies (1.44MB) are already obsolete because the LS-120 Super Drive (120MB) can store about _____(7) times the equivalent of a floppy, and Zip Drives (100MB, 250MB, etc.) are able to store about _____(8) floppies!  LS-120 can read and write standard floppy disks as well.
2. Hard disks, currently reaching double digit GB ranges, have the advantage of being the fastest mass storage but are permanent (i.e. the storage disks can not be switched).
3. Removable cartridges have hard disk capacities and are switchable.  Consequently, a drive has virtually unlimited storage potential.
2. Magneto-optical disks are removable and have removable gigabyte storage capacities.  Unfortunately they are sometimes mistakenly categorized as optical disks because lasers are used to read and write data.  However, the data is actually stored on magnetic media.  The laser technology allows high density storage and thus large storage capacity, but this is currently compromised by a slow access time compared to hard disks.
3. Read/write capability has only recently been made possible on Optical media.  (CD-ROMs have been available for a long time, but they are read-only.  Also WORM (write once, read many) drives can not be used as secondary storage because data can be stored on them only once.)  True read/write technology, however, is becoming available and will, no doubt, revolutionize secondary storage capabilities.  Technologies include:
1. CD-RW drives, which have read/write capability at CD-ROM capacities (650MB), appeared in 1997. They can read CD-ROMs and can write to CD-R disks, but a CD-RW disk can only be read by a CD-RW drive.
2. DVD (which originally stood for digital video disks but now means digital versatile disks) is a new read/write optical storage technology that has two competing technologies.  DVD-RAM, backed by Hitachi, Panasonic, Toshiba, and others, can store 2.6GB per side and DVD+RW, backed by HP, Phillips, Sony, and others, can store 3.6GB per side; both types of drives can read DVD-ROM and all CD formats.  Currently their read/write times are less than hard disks.
4. USB Flash drives are flash memory devices that plug into a USB port to serve as secondary storage.  (Unfortunately they are also (confusingly) called by many names including "flash drives", "pen drives", "keychain drives",  "jump drives", etc.)  Small and light enough to hook onto a key chain or hang on a necklace, they serve as efficient (faster data transfer than disk media),  portable secondary storage devices that allow data to be easily transferred from one machine to another.    Some products include synchronization software that keeps files updated between computers.
1. Flash memory gets its name because the memory chip is designed so that a block of memory cells are erased, together, in a single action or "flash."
2. Drivers are not required for the latest operating systems, but are available on the Web for legacy systems such as Windows 98 and Mac OS 8.
A really neat Web site for comparison shopping for hardware is PRICE WATCH, whose URL is www.pricewatch.com/
4. Data communications is the central theme of this course, so basic communications hardware, especially that associated with Internet access, is covered in the next learning module, REVIEW/OVERVIEW OF COMMENDATIONS AND NETWORKING.  The overall picture includes the following.
1. Data communications is a general term that has two subcategories:
1. Networks involve groups of computers.  (See section 1.5, below.)
2. Telecommunications is the technology that facilitates long distance communications between computers.  This overlaps with networking when more than two computers are involved.
2. Advances in data communications have reoriented computing from a centralized system based on mainframes to distributed systems in which data and computing power is made to available to numerous, non-local users and all resources may be shared.  This trend will continue towards a goal of optimal distribution that is dynamic, i.e. systems will reconfigure themselves so that they offer the maximum facilities to the users currently on-line.

      Software is a generic term for instructions that a computer can execute. Self-contained software is essentially synonymous with computer programs. Most textbooks classify software into two categories.  (I prefer three; see the concluding paragraph of this section.)

1. Application software includes programs that turn the computer (a general purpose tool) into a special purpose tool.  These include:
1. general productivity software like word processors, electronic spreadsheets, database management systems, graphics packages, etc.
2. education/entertainment software like tutorials, training programs, games, etc., and
3. professional software for use in business, science, medicine, etc.,
2. System software includes programs that allow users and their application software to utilize the computer resources (the computer itself, all its peripheral devices, and networks to which it is connected).  In general, system software has three subcategories:
1. system management software, e.g. the operating system (OS), networking, telecommunications, etc.,
2. system support software, e.g. utilities, device drivers, system monitors, maintenance, etc., and
3. system development software, e.g. programming languages, software engineering tools, etc.

1.5 Network Concepts (See the second Learning Module,  REVIEW/OVERVIES OF COMM. & NETWORKING.):

1. Computer Networks are the result of the reorientation of computing design from early isolated centralized systems based on huge, expensive mainframe computers with numerous user terminals to distributed systems in which data and computing power is spread over all networked users thus allowing all networked resources to be shared.
1. Distributed computer systems offer a robust alternative to multiuser computers.   In a multiuser system, if the central computer "goes down" every user is out of luck; in a distributed computing environment when a computer malfunctions only the user of that computer is effected.  (See Figure OOC-4A for a comparison of distributed computer systems versus the PC.)  Three versions of distributed PC systems are:
1. The new "Network Computers" (NCs as opposed to PCs) are being based on the idea that "the network IS the computer!
2. Networked workstations, e.g. Windows NT workstations, are PCs that are interconnected as well as connected to printers, servers (e.g. file servers which are computers whose hard disk is accessible to everyone in the network), net modems, etc.
3. NetPCs are stripped down PCs (but containing local secondary storage) designed specifically to be part of a network via which they access data, application software, etc.  Their locally stored software are installed, maintained, and updated, via the network, under centralized control.
2. Networks consist of interconnected "nodes" that interact via a client-server model  or peer-to-peer model.
   
1. The client-server model is the dominant
1. Servers are network computers which provide resources to the user of the network. Server software are applications that are stored on servers but which can be accessed by users without downloading them to their local hard disk.
2. Clients are computers at which users access servers on a network. Client software, running on a networked computer, is specifically designed to access server software, pass requests to it, and communicate results to the user.  In Figure OOC-4B the particular client software is a database management system; when a query is made, instead of downloading the whole database and searching on the client, the query is processed on the server and only the results are passed back to the client, a much more efficient use of resources.
2. The peer-to-peer model...
   
 

FIGURE OOC-4A

 

FIGURE OOC-4B
Simplified Client/Server Schematic

NOTE: The terms "client" and "server" are confusingly used to refer to the software as well as the computers on which they run.

2. Types of Computer Networks:
1. A Local Area Network (LAN) is the smallest kind of network designed to serve users within a confined geographical space, like a room or building.
2. A Wide Area Network (WAN) , e.g. the __________(9), covers a wide geographic area such as a state, a country, a dispersed corporation, or the world. They usually consist of subnetworks and incorporate common carriers that are licensed and regulated by government agencies providing telecommunication services for the public.  Note that "POTS" (Plane Old Telephone Service) is analagous to a WAN, but the latter is usually reserved for the description of networked computers, not POTS.
   
3. A Metropolitan Networks (MAN ) is a less frequently used term that refers to networks larger than LANs but smaller than WANs, large corporate networks at a single location.
4. Value-added networks (VAN) (e.g. GTE's Telenet and Tymshare's Tymnet) are public data networks, accessible via modem, for organizations that find private networks unfeasible. They make long distance connection to computing services less expensive than normal telephone service.
5. In a switched network a temporary connection is established between two network terminals for each individual communication. Data is transmitted from sender to receiver by three types of switching:
1. circuit switching (transmission only if receiver is ready) requires that a constant sender to receiver circuit be maintained for the duration of a transmission.
2. message switching is permanent, like circuit switching, but the connection is automatic, and
3. packet switching (message components , called "packets", may follow different routes). Unlike                    (10) switching, which requires a constant point-to-point connection to be maintained, each packet contains the destination address and a number specifying its position in the message sequence. This allows each packet to be "dynamically routed" over any network link as they become available or less congested. The destination computer reassembles the packets back into their proper sequence. The dynamic routing capability of the Internet makes it virtually indestructible, because when any link "goes down" the network itself will automatically reroute the message packages, unknown to the sender or receiver.
6. Dedicated (nonswitched) lines may be leased as network channels for the exclusive use of organizations transmitting large amounts of data.

2. THE INTERNET:

2.1 The Internet is a Wide Area Network (WAN:

1. The Internet (with a capital "I") is a network of networks within which all devices communicate via the TCP/IP protocol suite (See below.). It is a "meganetwork" linking hundreds of thousands of networks, at lmillions of hosts and countless people in every country of the world.. The latest density of computers on the Internet is shown if Figure OOC-5. The Internet links government agencies, educational institutions, businesses, libraries, science foundations, non-profit organizations, etc.  (Also check out the various fascinating maps from An Atlas of Cyberspace; however, be aware that some of these pages take a long time to access because of their complex graphics.)
1. It is impossible to determine the actual size of the internet, because it is so volitile.
1. Anyone can connect to or disconnect from the internet, so the number of people on the internet fluctuates wildly.
2. Perhaps the best measure of the size of the Internet is the number of hosts, monitored by the Internet Domain Survey.
   
3.  See the MIDS graph of Internet growth.)
2. No one runs the Internet; it is like a cooperative, i.e. a federation of independent networks. The Internet Society, a non-profit group in Reston, Va., promotes the use of the Internet
3. It has an open architecture, meaning anyone can connect up and use it.
4. It is a chaotic source of undisciplined information, an often bewildering maze to navigate.
FIGURE OOC-5
The Density of Computers in the Internet
(For a larger version of this illustration click here.)

2. Evolution of the Internet....incorporate:

1. Lessons for the Future Internet: Learning from the Past
   Educause Review (08/06) Vol. 41, No. 4, P. 16; Roberts, Michael M.

   1. "First president and CEO of ICANN Michael Roberts outlines four stages of the Internet's growth, noting the role that academic contributions have played.
   1. The first stage was characterized by federally funded research and the creation of NSFNet II, while
      
   2. The second stage saw enthusiastic academic usage and further development of the Internet, which led to the foundation of what would eventually be Internet2.
      
   3. The third stage of Internet growth saw the Internet reach and exceed both international and domestic saturation, and the U.S. government subsequently made ICANN responsible for the network's technical administration; however, ICANN has for the most part failed in its mission to function via broad consensus mechanisms, owing to the growing politicization of the Web.
      
   4. The fourth stage of growth involves the maturation of the Internet into a global and universal network that reflects human society, and with it has come renewed national and international concern over Internet policy, specifically the use of the Internet to meet social objectives, the extent of governmental economic Internet regulation, and the degree to which network users' expectations for privacy should be preempted by national security priorities. The existence of legislation dealing with each of these issues makes the challenge to lawmakers twofold: They must determine the proper role for governments to play as the Internet's growth and development continues, and also how societies worldwide switch from antiquated technology and laws to a new balance between society, technology, and politics. Roberts says the academic community, on the strength of its open and collaborative nature, can be a vital player in the Internet's continued evolution. The author cites several areas where academic support and advocacy is critical, including federal funding for university research into networking; the provision of universal affordable broadband and middleware; the use of academic network facilities as testbeds for advanced technologies, such as converged voice, video, and data; and the preservation of the Internet commons."

   2. Click Here to View Full Article

3. The Internet can be thought of on three levels:
1.  A physical network: it is a World Wide Network (i.e. a                  (11) that is a maze of telecommunication lines which interconnect smaller networks.  For example our Compton laboratory networks are part of the FSU network which is part of the University of Maryland System network which is part of the Internet, but technically every FSU network computer is part of the Internet.
1. Internet access is provided by ISPs (Internet Service Providers), companies that maintain Internet connections and rent their services to other ISPs or individuals.  In general, there are three categories of ISPs, local, regional, and national. (See Figure OOC-6.)  The national ISPs, like MCI, Sprint, AT&T, etc. maintain "backbones" that act as "trunklines" that carry huge composite transmissions over long distances.See Mapnet,a super, customizable tool for viewing the infrastructure of multiple ISPs.  In the U.S., access points to these backbones and the places where data moves from one backbone to another are one of two types ( See Shelly & Cashman Figure 7-6.):
1. A new acronym, ASP for application service provider describes an extension of ISP services, i.e. a company that offers, to subscribers, access over the Internet to applications that would otherwise have to be purchased. (Such applications are referred to as "Web services" or "apps-on-tap,")  
1. Web services are Web based applications, utilizing open standards, that encompass diverse resources such as storage management, Web site hosting, stock market investing, business transactions, etc.
   
2. Web services are expected to become a popular way of "outsourcing" costly development activities. 
3. (Don't confuse application service provider with the Active Server Provider, and Active Server Page both also abbreviated as ASP.)
4. Web services are covered in more detail in LM IV.
   
2. NAPs (network Access Points), also called Internet Exchanges (IXs), are junction points where national ISPs interconnect with each other.
3. MAEs (metropolitan area exchanges) are NAPs that are strategically located to facilitate efficient transfers between different backbones.
2. Another interesting representation of the infrastructure of the Internet as a whole is displayed in the Map Gallery of the Internet Mapping Project.
3. More information about ISPs and backbones can be found at Boardwatch's informative Web site,
http://boardwatch.internet.com/
4. In the idealized illustration below, a user would access their local ISP in Doylestown via a modem.  The local ISP links to the regional ISP which, in turn, links to the backbone of a national ISP.  Every computer in this schematic is part of the Internet (The individual using a modem is only temporary.); this graphically illustrates that the Internet is a network of networks.  For a thorough comparison of commercial ISP see CNET's analysis.

FIGURE OOC-6
Subnetworks of the Internet and Their ISPs

5. For a better idea of the backbones in operation in the U.S. click here.  Also see Shelly & Cashman Figure 7-7.
6. Every device connected to the Internet has an Internet address that has two forms:
1. The numeric IP address is used by the computer system and network.  It is a four byte number expressed, for humans, as four decimal numbers separated by periods, such as "131.118.80.1" (the IP address of the DNS server at FSU). Valid addresses thus range from 0.0.0.0 to 255.255.255.255, a total of about 4.3 billion addresses!
2. The URL (Uniform Resource Locator) is a more understandable text address, used by humans, that contains the "name" of the computer that corresponds to its IP address.  For example the URL of this Web page that you are reading contains "www.frostburg.edu" which is the domain name of the server on which the Web site of this course is stored.  This name must be translated to its IP addresses before they can be used by networked computers; this translation is the job of the DNS server (mentioned above). See Shelly & Cashman Figure 7-6. (Note: the rest of the text in the URL specifies the protocol (http) used and the specific location of this page in the computer's files.  This will be covered in section 1.5.B of L.M. III.)
NOTE: Internet addresses should not to be confused with and e-mail address.
2. A collection of protocols which are conventions (rules) that govern the translation of digital data into and out of "packets" of binary data which can be transmitted over a network, e.g. the Internet. Protocols govern format, timing, sequencing, and error control. Without these rules, a computer cannot "understand" a stream of bits coming to its network connection. The protocols particular to the Internet are part of TCP/IP (Transmission Control Protocol / Internet Protocol) which is actually a collection, or "suite", of protocols which form the basis of communications over the Internet. They are routable (i.e.                  (12)  Switching) protocols which means transmissions are broken into packets which may be sent over different routes before arriving at a single destination where the packets are reassembled into the original message. (The terms "intranet" and "extranet"  refer to corporate networks based on TCP/IP; see section 4.B.)  Two of the TCP/IP protocols that govern your Internet connections are:
1. SLIP (Serial Line IP) is a TCP/IP protocol that allows IP packets to be transmitted over a serial connection (via which bits are sent sequentially instead of simultaneously), such as a modem.
2. PPP (Point to Point Protocol) also provides serial modem access but is more advanced than SLIP. In addition to SLIP capability, PPP can establish and terminate a session as well as hang up and redial on a low quality call.
Note that other network protocols, e.g. NetBIOS (IBM networks), NetBEUI (Microsoft), IPX (Novell networks), DECNet (DEC), etc., will be ignored in this course because they are not associated with the Internet.
3. An ever increasing, conceptual network of Internet resources accessed by Internet services. (See section 2.2.) The resources are typical client-server environments.

        Internet services are provided by application programs that implement protocols that are components of the TCP/IP suite. (NOTE: Most of these services are not unique to the Internet, e.g.. e-mail, chat, etc. but others are specific to the Internet, e.g. the World Wide Web.) They fall into three categories:

1. Communication Services.  (For more details see Learning Module III, section 3.)
1.  E-mail enables Individuals to exchange electronic messages; it is a network facility that provides users with a "mailbox " file, where messages are stored. Correspondence can be directed to specific users (with security) as well as to specified groups. Local mail is sent via the "mailer" program in system software. Non-local e-mail is routed over a               (13) such as the Internet. See Shelly & Cashman Figure 7-31.
1. E-mail includes "Talk" or "Phone"services which, like "chat" (See 2.2.A.d, below.), facilitate real-time, interactive text transfers (not voice) between two Internet users.
2. SMTP (Simple Mail Transfer Protocol), POP (Post Office Protocol), and IMAP (Internet Message Access Protocol) are e-mail protocols of the TCP/IP suite.  Both POP and IMAP use SMTP for communication between the e-mail client and server, but they make e-mail more user friendly.  POP allows users to download e-mail from a mail server to a PC where it can be read, answered, and stored on a hard disk.  IMAP is even better because it allows you to manipulate your e-mail account on the server.
3. Note that Web based e-mail accounts, like  Yahoo Mail and FSU's Sun Interface, use the Web procol, HTTP, as an interface to their e-mail servers.  (See section 2.2.C.a, below.)
2. Forums, electronic bulletin boards and newsgroups
1. Newsgroup Services (e.g. Usenet or Internet News) exchange messages called articles arranged according to specific categories called newsgroups. Here the messages are passed from one system to another, not between individuals using e-mail. Unlike mailing lists these transmissions are not automatic, they must be requested by the user via local client software.
3. Mailing lists allow computers to subscribe to the mass communications on a specified subject. Any e-mail received by a mailing list server is automatically forwarded to all subscribers.
4. Chat/IM applicationsfacilitate real-time group communication by enabling users to join rooms or "channels" where all members receive a copy of a message sent to the channel they are visiting. (Private conversations can be arranged.) IRC (Internet Relay Chat) was the first such application but is limited to text messages.
1. Instant Messenging (IM or IMing) is a modern extention of chat technology that adds features like "buddy lists", automatic notification when a buddy comes online, multiperson conferences, user profiles, filters, message histories, etc.. Popular IM applications include AIM (AOL IM), ICQ (for "I seek you"), Yahoo messeger, and Microsoft Network Messenger Service (MSNMS).   A public domain IM is Jabber.
2. Some  chat application utilize multimedia to create virtual reality (VR) environments where users can assume an identity, called an "avatar", which moves through the chat environment interacting with the avatars of other users.
5. Teleconferencing refers to real-time computer-based, audio/video interaction of two or more remote stations. Apparently, current chat applications are evolving into full featured teleconferencing software.
1.  Audio communication became possible using microphones and computer speakers.
2. Graphics communications allow both users to type or draw on a common "whiteboard" or even modify an image loaded from a graphics file. The Netscape Conference is Communicators teleconferencing facility that allows audio and whiteboard communication.
3. Video communication is possible using images from digital cameras. The freeware applications Microsoft NetMeeting (which we will use during this course) and iVisitprovides this between microcomputers. Multimedia transmissions require huge bandwidth so at present teleconferencing applications and "Video Phones" are rather primitive, especially if they involve color video transmissions between microcomputers.
4. A good resource on all types of Internet conferencing (including chat, IM, etc.) is About Internet Conferencing.

2. Resource access services. (For more details see Learning Module III, section 2.)
2. File Transfer allows a network user to copy a file from one computer to another. It is typically used to "download" public domain (free) software or shareware (minimal cost paid, on an honor system, after a trial period) which has been "uploaded" (copied from a users computer to the file server). FTP (File Transfer Protocol) is part of the TCP/IP suite. Archie is FTP's associated search engine; it indexes FTP sites so that the user can determine what is available. An Archie search scans FTP sites and then offers a searchable database of the files it finds. These can then be downloaded via FTP. Archie has lost significance with the growth of the Web, but FTP is still the vehicle used to move files on the Internet.
3. Remote Logon allows a computer user to access another (multiuser) computer, i.e. to log on to and use that computer as if his/her computer were directly connected to that computer. The user's CPU and operating system are "bypassed" and the user's computer simply becomes a terminal connected to the remote computer. The Telnet protocol provides this in TCP/IP.
3. Information retrieval services unique to the Internet.  (For more details see Learning Module III, section 1.):
1. TheWorld Wide Web (WWW or W3) is called "THE Internet Killer Application" because its popularity is literally exploding! Since 1994 it has not only dominated all other WANs (See the next section.) but all other services of the Internet, itself. "The Web" enables users to "browse" documents on remote servers using the HTTP (hypertext transfer protocol, a member of the TCP/IP suite). Everything (documents, menus, pictures, etc.) is represented to the user as a hypertext object (where clicking on the object activates a link to another object which can be within the document, in another file, or on another Internet resource).
1. Web "pages",  are accessed by a "browser" (e.g. Netscape Navigator) running an HTML (Hypertext Markup Language)program. "Search engines" are programs that allow browsers to search for Web pages with specified key words. Browsers actually provide many of the other TCP/IP services such as e-mail and FTP, which are usually built in, and remote logon which is added by "plug-in applications".
2. VRML (Virtual Reality Modeling Language) is a developing standard that is designed to allow users to view the Web as a 3D virtual environment. The WWW has been
2. Gopher/Veronica allows the user to access files on remote servers; the file names are presented as hierarchical menus. Veronica is a "search engine" which allows one to look for specific information on gopher servers, but, like Archie, is insignificant compared to the Web.
3. WAIS (Wide Area Information System) is an automated Internet search service that allows users to locate documents containing key words or phrases, but, like Archie and Gopher/Veronica, has been almost completely superseded by the Web.

 

3. NETWORKS OTHER THAN THE INTERNET (not based on TCP/IP):

3.1 Other Public Networks: 

NOTE: The explosive growth of the Internet has overwhelmed the following public networks and in some cases, e.g. Bitnet, is causing their demise.  See the MIDS graph of the growth of public networks.

1. BITNET (Because Its Time NETwork) is a network of educational sites that provides interactive electronic mail and file transfer services using a store-and-forward protocol based on IBM Network job Entry protocols. It is separate from the Internet; however, e-mail is freely exchanged between Internet and BITNET. This is probably the only WAN that is currently shrinking; it has virtually disappeared in the U.S.  (Click on the preceding link to MIDS.) This is because the Internet makes it redundant.
2. FidoNet is the largest BBS network, offering hundreds of what are called "echoes" (or sometimes, "conferences") which are messages on specific topics contributed by BBS users all over the world. A FidoNet BBS may carry all the FidoNet echoes or a selected few.
3. UUNET (UNIX to UNIX NETwork) provides news, e-mail, and an extensive library of UNIX software. UUCP, the UNIX utility that copies a file from one computer to another is analogous to           (14) on the Internet. Unlike TCP/IP, which is a                                                 (15) communications protocol, UUCP provides a point-to-point transmission where a user at one UNIX computer dials up and establishes a session with another UNIX computer for the complete duration of the communication.

1.  Academic networks like those in the University of Maryland System (identified by the ".umd" part of their Internet address) and the subnetwork here at FSU (identified by the ".fsu" part of their address).  Since all the academic networks of U.S. schools on the Internet end with the ".edu" extension, the Internet address of any computer connected to any FSU network would end with  ".fsu.umd.edu"
2. Corporatenetworks designed for employees of the company.
1. The term "intranet" is now being used to describe MANS or corporate networks that are, strictly speaking, based on TCP/IP; however, the meaning of the term is being generalized to refer to a corporate network using any protocol.
2. An extension of corporate  network  that connects  the customers, suppliers, and other closely associated organizations of the corporation is called an "extranet".  (Again, strictly speaking, an extranet is based on  TCP/IP.)
3. Government networks.
4. Military networks.

3.3 Online Services:

1. Online services, such America Online (AOL), CompuServe(In 1997 its content was purchased by AOL and its network by WorldCom, but it still retains its identify on the Internet.), and Prodigy (now owned by Yahoo), and MSN (Microsoft Network) allow subscribers to access, for at fee, a collection of online information utilities including:
1. a variety of BBS, forums, chat facilities, and file servers for downloading the latest information, software, etc.
2. up-to-date information (databases, encyclopedias, stock market quotes, reviews, news, etc.)
3. services (e-mail accounts, financial services, reservations, online shopping, advertisements, etc.)
4. access to the Internet.
2. Special purpose Information Utilities are maintained for professional organizations.

3.4 Other Telecommunications Facilities:

1. Electronic data interchange (EDI) facilitates the electronic transfer of data between organizations in order to replace paper forms. When combined with e-mail and WWW, EDI has the potential to revolutionize commerce.   X12, the ANSI standarde for EDI, is being merged with an international standard, EDIFACT.
1. Data, in an EDI message, is encaspulated within a data segment that contains a string of data elements,separated by delimiters.  Each data element contains a unique data value, e.g. a person's name or social security number or address, etc. Each data segment is delimited by a header and a trailer
2. An EDI transmission is a collection of related segments which is called a transaction set, which would typically contain a complete business exchange such as a completed form.
   
3. The sender and receiver of EDI transmissions are called trading partners.
4. EDI services increasingly are likely to become Web services.
2. Electronic funds transfer (EFT) allows financial transactions via telecommunications; this facilitates home banking, investment transactions, etc.
3. Telecommuting is a term used for workers who access their organization's computer facilities, via modem, from their home, thus avoiding the commute to work.
4. Global positioning Systems (GPS) is a satellite based geographic locating system that can pinpoint a GPS device to within 100 feet. Currently there are 24 satellites in geosynchronous orbits, and at any given moment, at any point on the earth's surface there are between 6 and 9 satellites above the horizon capable of transmitting to GPS receivers on earth.  It is being incorporated in:
1. tracking systems,
2. navigation systems, and
3. mapping systems.
If you are interested, check out the description in the interesting Web Site, How Stuff Works.
5. Online Bulletin Board Services (BBS) (now made virtually obsolete by the Web) are  online computers that allow subscribers to access them via modem in order to:
1. communicate with one another via a public message system (usually at no charge),
2. obtain BBS data, and
3. obtain Public Domain Software or                  (17) Software may be downloaded (copied from the BBS file server). With permission from the sysop (system operator) software can be uploaded (copied to the BBS) so that other subscribers can access it.
Most BBS have been replaced with Web Pages, which are more user-friendly as well as more functional.

4. MALWARE AND INTERNET SECURITY:

1. "Malware" (a portmanteau  for malicious software)  is fraudulent software that is designed to invade computer systems without notice. It may simply have a mischievous intent like leaving an "April Fool's" message on the screen or it may be maliciously designed to damage other software and data.
2. Various forms of malware include:
1. Viruses: a self-replicating code that invades a computer system by attaching itself to ("infecting") other commonly used host programs. Malicious forms can erase data or damage hardware. Polymorphic viruses are the hardest to identify because they are designed to change their appearance each time they attach themselves to a new program.  Classic examples include the CIH (Chernobyl strain) and Melissa.  For more information on viruses see the About.com article.
1. Most viruses can only attach itself to program files, not data files. However, they can migrates through networks attaching themselves to different programs. For example, when a user accesses a computer system with a virus, it attaches itself to a program file which may be subsequently stored on a floppy disk or hard disk, thus moving on to any system to which the infected disk is attached. As long as it goes undetected in a computer system, it will continue to infect every program coming into contact with it.
2. Worms: self-contained, self-replicating programs that continuously duplicates itself until it fills all available memory.  The most famous worm was the "Internet Worm".
   
3. Bombs non-replicating software, usually introduced by people within an organization, that delete critical files or otherwise damage the system when a specific event occurs. Time bombs activate at a predetermined time and date; Logic bombs activate when the host program performs a specific action.  Bombs can contain viruses and worms.
4. Trojan horses: non-replicating code, hiding inside other programs, that are designed to locate password information, or otherwise make unauthorized access to software or data. Trojan horses can contain viruses, worms, bombs or other malware.  A prevalent example of Trojan horse is spyware.( See section vi, below.)
   
5. Denial of Service Attacks (DSA) are different from the previous types in that the security of a network node is not violated, i.e. code has not been placed on the target computer.  Instead Denial of Service effectively shuts down a computer service, e.g. a Web site, by swamping it with repeated computer generated requests for service; this prevents legitimate requests for the service to get through and can be used for extortion.  Denial of Service Attacks are necessarily assoicated with another misuse of networks, "spoofing" (generating a fake IP address in order to gain access to a network resource). A specific type of DSA on the Internet is called "smurfing".   For a more detailed description of DSA access

6. Spyware  is software that covertly collects information about a computer user's activities (ususally on the Internet).  It typically installs itself, without the user's knowledge, and then "spys" on the user's actions, secretly transmitting these to an information gathering and analysis center.  (Technicaly "Legal", spyware often embedds installation permission within verbose liscence ageements that users typically agree to without readingthe details.)  Spyware typically monitors Web browsing activities, collects e-mail addresses, snoops for personal data such as passwords, credit card numbers, etc.  The danger is that spywre, unlike _____________(1), spyware is designed for profit; this may be as innocent as observing browsing habits for target advertising or as malicious as identity theft, finacial theft, etc.  See the Flash Demo about Spyware from Trend Micro.

1. Examples of malicious spyware include:
1. Keylogger (also called keystroke logger) which copy keystrokes of the user, typically for the purpose of identity theft and credit card fraud by stealing passwords, credit card numbers, social security numbers, and other personal information. Keylogger spyware usually encorporats two kinds of files, a dynamic link library (.dll), which does the recording and an executable file (.exe) that installs the DLL file and runs it.
   
2. Event loggers which monitor the user's activities like Web browsing habits, application uses, chat communications, etc.
   
3. Fraudulant Dialers which (from Wikopedia)
   
1. replaces the phone number in a modem's dial-up connection with a long-distance number, often out of the country, in order to run up phone charges on pay-per-dial numbers, or
   
2. dials out at night to send keylogger or other information to a security cracker.
4. Hijackers (Tony's term) which surreptitiously take control of an online computer.  These can be used to create
   
1. a botnet (robot network), which is a large "zombie network" of "bots" (autonomous programs) that are remotely controlled in order to create mischief on a network without the knowledg of the owners' of the "zombie computer". 
   
1. Bots can spawn denial-of-service attacks, distribute spam (unsolicited e-mail), facilitate identity theft and credit card fraud, perform espionage, automate the process of clicking on ads that generate per-click revenue, etc.  Former Arbor Networks researcher Jeremy Linden says, "Bots are at the center of the undernet economy. Almost every major crime problem on the Net can be traced to them."
2. While viruses are ____________(2a)  that __________(2b) themselves, bots are controlled by a remote server and work together to do damage to network computers.
3. References:
1. Attack of the Bots from Wired Magazine.
   
2.  the Attack of the PC Zombies and Zombie Repellant.
2. Browser Hijackers which are programs designed to alter, from a remote computer, a target computer user's browser settings.  For example, a browser hijacker may change the default home page in the user's browser, add shortcuts to a browser's bookmarks, lower security settings, etc.
2. Spyware is normally a type of freeware or shareware that is, in fact, a Trojan horse that is unknowingly installed as part of another application.  Typically this occurs when using peer-to-peer file swapping applications.  
3. Although it has a "bad name", spyware is not necessarily malicious.  For example spyware is typically used for advertising purposes, i.e. adware (software that displays advertisements on computers) can be tailored to the user's interests characterised by his/her Web browsing activities.
   
1. Cookies should not be confused with spyware; they are legitiment data files that allow a Web server to identify users and maintain their logon information. Cookies may be temporary (for a single session only) or persistent (permanently stored on the user's hard disk and uploaded whenever the user accesses the server).  In the case of persistent cookies, the server creates the cookie and downloads it to the user's computer.
   
2. Keyloggers can be used by companies as a surveillance tool to monitor employees' compute use, or by parent's monitoring their children's Internet activities.
   
4. For more information see Inside Spyware from the Intranet Journal.  Also see
1. the top ten spyware threats most frequently identified by Webroot's Spy Audit, a free spyware scanner tool
2. Trend Micro's  Eight Symptoms Your Computer Is Infected.

3. There are several ways malware can enter your system, including e-mail attachments, file sharing, infected secondary storage media, downloads (especially freeware, shareware, or browser plug-ins), etc.
4. Once malware is in a system it may lay dormant until a particular date or some event triggers its execution.
5. Another problem associated with malware is mass overreaction to the threat of such software.  In interesting site that focuses on this is: Computer Virsu Myths, at http://kumite.com/myths/