Prior to learning about IT security it is significant that you have a basic understanding of computer networks and data communications. Below are some questions and answers that encompass this area.
1. What is the definition of:
a. a computer network? A computer network is an interconnection of computers and computing equipment using either wires (such as optical fiber, twisted pair wire, coaxial cable, phone lines, power lines) or radio waves that can share data and computing resources. These resources also include hardware, such as storage media and peripherals and software. Computer networks that use radio waves are termed wireless and involve broadcast radio, microwaves and satellite transmission.
b. data communications? The encoded transmission of data via electrical, optical or wireless means between computers and network processors. Data communications often uses the process of breaking down a message into small packages and when the message arrives at its intended destination the packages are put back together in sequential order to resemble the original message.
c. telecommunications? Telecommunications is the process that enables one or more other users information of any nature delivered in any usable form by wire, radio, television or other electrical, electromagnetic or optical means. As you described in class Telecommunications is derived from the Greek word “tele” meaning far off.
d. a local area network? A local area network (LAN) is a network designed to connect personal computers and other digital devices within a half a mile or 500 meter radius. LANs usually connect a few computers in a small office, all computers in one building or all computers in several buildings in close proximity. LANs are also used to link to other forms of networks around the world using the Internet.
e. a personal area network? A personal area network (PAN) is networks spanning an area of several meters around and individual. PANs include devices such as laptop computers, personal digital assistants (PDAs) and wireless connections such as bluetooth technology.
f. a metropolitan area network? A metropolitan area networks (MAN) are networks that that serve an area of up to roughly 50 kilometers. The network usually spans a metropolitan area, usually a city and its major suburbs therefore its geographic scope usually falls between a LAN and an WAN. This is a high speed network that connects businesses with other businesses and the internet.
g. a wide area network? A wide area network (WAN) are large networks than span broad geographical distances; over states, multiple states, countries and the world.
h. network management? Network management is the design, installation and support of a network and its hardware and software. In other words such functions include planning, coordination, deployment, security and monitoring. Network management is also governed by a large number of protocols.
i. convergence? Convergence is the merging of both voice and data networks and over time networks have seen different network applications and the technologies that support them converge into a single technology capable of supporting these various applications.
2. What is the relationship between a sub-network and a node? A sub-network consists of the nodes (computing devices that allow workstations to connect to a network & make decisions where to route the data) and transmission lines, collected into a cohesive unit. In other words the sub-network is the underlying physical system of nodes.
3. What kind of applications might use a computer terminal to mainframe computer connection? Applications that might use a computer terminal to a mainframe connection are inquiry/response applications, interactive applications and data entry applications. An example is an ATM machine to interact with your bank account or applying for a new driver’s license at the DMV.
4. What kind of applications might use a microcomputer to mainframe computer connection?
Some applications that might use a microcomputer to a mainframe computer connection are terminal emulation cards, web browsers & web interface, Telnet software or a thin client.
5. What language does a microcomputer have to talk to interface to the Internet? The language a microcomputer would have to use to interface with the Internet is Transmission Control Protocol/Internet Protocol better known as TCP/IP.
6. What kind of applications might use a sensor to local area network connection? Applications a sensor connected to a LAN may be used in the paying of bridge and tunnel tolls through EZ pass, sensors embedded in roadways to trigger traffic signals, Assembly lines, RFID sensors used in retail stores for security purposes in clothing tags, microchip sensors embedded in animals to track them down via global positioning systems (GPS) and GPS network meteorological sensors to determine weather patterns. There are numerous applications.
7. Why is a network architecture model useful?
A network architecture model is useful because it acts as a blueprint providing a framework to assist in how the various components of a network should interoperate. In other words it’s the technological foundation for designing, building and managing a network. The models are composed of layers which aid in the organization of a network’s components as each layer performs a different task. The network as a whole would not be able to function without the proper operation of each of the layers.
8. List the seven layers of the OSI model.
The top layer of the OSI model number 7 is the application layer where users communicate with the computer. Its main functions are email, file transfers, remote logins and web browsing. The 6th layer is the presentation layer which presents data to the application layer in a format that can be processed by an end user. Some tasks include data decompression, compression, encryption and decryption. The 5th layer is the session layer which manages flow of data between 2 computers such as dialogue control, token management and synchronization. The 4th layer is the transport layer ensures data that the data packet that arrives at its final destination is identical to the one that left the point of origin. The 3rd layer is the network layer which is responsible for creating, maintaining and ending network connections and switches and routers are the devices of this layer. The 2ndlayer is the data link layer which is responsible for taking data from the network layer and transforming it into a cohesive unit called a frame. Functions include framing packets, sequence control, flow control, physical addressing of devices in the network and error control. The 1stlayer is the physical layer whose main function is to send and receive bits by handling voltage levels, plug and connector dimensions, pin configurations and other electrical and mechanical issues. The choice of wire or wireless transmission media is determined in this layer.
9. List the five layers of the TCP/IP protocol suite. The top layer is the application layer which supports the network applications and may include encryption and compression. Frequently used applications are HTTP, SMTP, FTP, Telnet and SNMP. The 2nd layer is the transport layer which commonly uses the Transmission Control Protocol (TCP) to maintain an error free end to end connection as well as User Datagram Protocol used less frequently. The 3rd layer is the network layer sometimes known as the internet layer. The Internet Protocol (IP) is used in this layer which is the software that prepares the packet of data that it can move from one network to the other over the Internet. The 4th layer is the network access layer sometimes called the data link layer is the layer that gets the data from the user workstation to the Internet. Finally the last layer is the physical layer which is where the actual transmission of data occurs which can be by wire or wireless.
10. How do the layers of the OSI model compare with the layers of the TCP/IP protocol suite?
The OSI model has 7 layers whereas the TCP/IP suite has 5 layers and in some cases some people use 4. TCP/IP is a working model currently used on the Internet and OSI is a theoretical model. OSI is a protocol independent model and TCP/IP is a protocol specific model. Both models give a good explanation on how various types of network hardware and software interact during the data communications process. Both perform routing in the form of packets. Each layer performs well defined functions in each model. A layer can be reconfigured in both models without hurting the model as a whole. The OSI model explains quite well the concept of services and protocols whereas TCP/IP makes no clear distinction between services and protocols. There are also error correction techniques in both models.
