Information Systems and technology

Q1. Compare between LAN, MAN and WAN?
A LAN (local area network) is a group of computers and network devices connected together, usually within the same building. By definition, the connections must be high speed and relatively inexpensive (e.g., token ring or Ethernet). Most Indiana University Bloomington departments are on LANs.
A LAN connection is a high-speed connection to a LAN. On the IUB campus, most connections are either Ethernet (10 Mbps) or Fast Ethernet (100 Mbps), and a few locations have Gigabit Ethernet (1000 Mbps) connections.
A MAN (metropolitan area network) is a larger network that usually spans several buildings in the same city or town. The IUB network is an example of a MAN.
A WAN (wide area network), in comparison to a MAN, is not restricted to a geographical location, although it might be confined within the bounds of a state or country. A WAN connects several LANs, and may be limited to an enterprise (a corporation or an organization) or accessible to the public. The technology is high speed and relatively expensive. The Internet is an example of a worldwide public WAN.

Q2. Explain the advantages and the disadvantages of using the following networks inbusiness:
a) Client/server networks?
b) Network computing?
c) Peer-to-peer networks?
a) Client/server networks
Advantages

A client server can be scaled up to many services that can also be used by multiple users.
Security is more advanced than a peer-to-peer network, you can have passwords to own individual profiles so that nobody can access anything when they want.
All the data is stored onto the servers which generally have far greater security controls than most clients. server can control the access and resources better to guarantee that only those clients with the appropriate permissions may access and change data.

Disadvantages

More expensive than a peer-to-peer network you have to pay for the start up cost.
When the server goes down or crashes all the computers connected to it become unavailable to use.
When you expend the server it starts to slow down due to the Bit rate per second.
When everyone tries to do the same thing it takes a little while for the server to do certain tasks

b) Network computing?
Advantages of Computing Networking
1. Easy Communication : and Speed It is very easy to communicate through a network. People can communicate efficiently using a network with a group of people. They can enjoy the benefit of emails, instant messaging, telephony, video conferencing, chat rooms, etc.
2. Ability to Share Files : Data and Information This is one of the major advantages of networking computers. People can find and share information and data because of networking. This is beneficial for large organizations to maintain their data in an organized manner and facilitate access for desired people.
3. Sharing Hardware : Another important advantage of networking is the ability to share hardware. For an example, a printer can be shared among the users in a network so that there’s no need to have individual printers for each and every computer in the company. This will significantly reduce the cost of purchasing hardware
4. Sharing Software : Users can share software within the network easily. Networkable versions of software are available at considerable savings compared to individually licensed version of the same software. Therefore large companies can reduce the cost of buying software by networking their computers.
5. Security : Sensitive files and programs on a network can be password protected. Then those files can only be accessed by the authorized users. This is another important advantage of networking when there are concerns about security issues. Also each and every user has their own set of privileges to prevent them accessing restricted files and programs.
6. Speed : Sharing and transferring files within networks is very rapid, depending on the type of network. This will save time while maintaining the integrity of files.
Disadvantages of Networking
1. Breakdowns and Possible Loss of Resources : One major disadvantage of networking is the breakdown of the whole network due to an issue of the server. Such breakdowns are frequent in networks causing losses of thousands of dollars each year. Therefore once established it is vital to maintain it properly to prevent such disastrous breakdowns. The worst scenario is such breakdowns may lead to loss of important data of the server.
2. Expensive to Build : Building a network is a serious business in many occasions, especially for large scale organizations. Cables and other hardware are very pricey to buy and replace.
3. Security Threats : Security threats are always problems with large networks. There are hackers who are trying to steal valuable data of large companies for their own benefit. So it is necessary to take utmost care to facilitate the required security measures
4. Bandwidth Issues : In a network there are users who consume a lot more bandwidth than others. Because of this some other people may experience difficulties.

c) Per-to-per networks?

Advantages

Easy and simple to set up only requiring a hub or a switch to connect all computers together.
You can access any file on the computer as-long as it is set to a shared folder.
If one computer fails to work all the other computers connected to it still continue to work.
Disadvantages

Security is not good other than setting passwords for files that you don't want people to access.
If the connections are not connected to the computers properly then there can be problems accessing certain files.
It does not run efficient if you have many computers, it is best to used two to eight computers.

Q3. How can Internet technologies help improve a process in one of the functions ofbusiness? Choose one example and evaluate its business value.
Internet technologies generally are accepted for improvements in data capture costs, data quality, cycle-time reductions, and increased information availability in an organizations. A simple example might include a web-based form through which customers may place their own product orders. Such a form would reduce transcription errors by shrinking the communications chain, enable real-time error checking, reduce telecommunications and labor costs, increase the organization's market space presence, and enable real-time transaction reporting.
Q4. What are the functions of seven layers of OSI model?
Layer 1. Physical Layer
The first layer of the seven layers of Open Systems Interconnection (OSI) network model is called the Physical layer. Physical circuits are created on the physical layer of Open Systems Interconnection (OSI) model. Physical layers describe the electrical or optical signals used for communication. Physical layer of the Open Systems Interconnection (OSI) model is only concerned with the physical characteristics of electrical or optical signaling techniques which includes the voltage of the electrical current used to transport the signal, the media type (Twisted Pair, Coaxial Cable, Optical Fiber etc), impedance characteristics, physical shape of the connector, Synchronization etc. The Physical Layer is limited to the processes needed to place the communication signals over the media, and to receive signals coming from that media. The lower boundary of the physical layer of the Open Systems Interconnection (OSI) model is the physical connector attached to the transmission media. Physical layer of the Open Systems Interconnection (OSI) model does not include the transmission media. Transmission media stays outside the scope of the Physical Layer and are also referred to as Layer 0 of the Open Systems Interconnection (OSI) Model.
Layer 2. Datalink Layer
The second layer of the seven layers of Open Systems Interconnection (OSI) network model is called the Datalink layer. The Data Link layer resides above the Physical layer and below the Network layer. Datalink layer is responsible for providing end-to-end validity of the data being transmitted. The Data Link Layer is logically divided into two sublayers, The Media Access Control (MAC) Sublayer and the Logical Link Control (LLC) Sublayer.
Media Access Control (MAC) Sublayer determines the physical addressing of the hosts. The MAC sub-layer maintains MAC addresses (physical device addresses) for communicating with other devices on the network. MAC addresses are burned into the network cards and constitute the low-level address used to determine the source and destination of network traffic. MAC Addresses are also known as Physical addresses, Layer 2 addresses, or Hardware addresses.
The Logical Link Control sublayer is responsible for synchronizing frames, error checking, and flow control.
Layer 3. Network Layer
The third layer of the seven layers of Open Systems Interconnection (OSI) network model is the Network layer. The Network layer of the OSI model is responsible for managing logical addressinginformation in the packets and the delivery of those packets to the correct destination. Routers, which are special computers used to build the network, direct the data packet generated by Network Layer using information stored in a table known as routing table. The routing table is a list of available destinations that are stored in memory on the routers. The network layer is responsible for working with logical addresses. The logical addresses are used to uniquely identify a computer on the network, but at the same time identify the network that system resides on. The logical address is used by network layer protocols to deliver the packets to the correct network. The Logical addressing system used in Network Layer is known as IP address.
IP addresses are also known as Logical addresses or Layer 3 addresses.
Layer 4. Transport Layer
The fourth layer of the seven layers of Open Systems Interconnection (OSI) network mode is the Transport layer. The Transport layer handles transport functions such as reliable or unreliable delivery of the data to the destination. On the sending computer, the transport layer is responsible for breaking the data into smaller packets, so that if any packet is lost during transmission, the missing packets will be sent again. Missing packets are determined by acknowledgments (ACKs) from the remote device, when the remote device receives the packets. At the receiving system, the transport layer will be responsible for opening all of the packets and reconstructing the original message.
Another function of the transport layer is TCP segment sequencing. Sequencing is a connection-oriented service that takes TCP segments that are received out of order and place them in the right order.
The transport layer also enables the option of specifying a "service address" for the services or application on the source and the destination computer to specify what application the request came from and what application the request is going to.
Many network applications can run on a computer simultaneously and there should be some mechanism to identify which application should receive the incoming data. To make this work correctly, incoming data from different applications are multiplexed at the Transport layer and sent to the bottom layers. On the other side of the communication, the data received from the bottom layers are de-multiplexed at the Transport layer and delivered to the correct application. This is achieved by using "Port Numbers".
The protocols operating at the Transport Layer, TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) uses a mechanism known as "Port Number" to enable multiplexing and de-multiplexing. Port numbers identify the originating network application on the source computer and destination network application on the receiving computer.
Layer 5. Session Layer
The position of Session Layer of the Seven Layered Open Systems Interconnection (OSI) model is between Transport Layer and the Presentation Layer. Session layer is the fifth layer of seven layered Open Systems Interconnection (OSI) Model. The session layer is responsible for establishing, managing, and terminating connections between applications at each end of the communication.
In the connection establishment phase, the service and the rules (who transmits and when, how much data can be sent at a time etc.) for communication between the two devices are proposed. The participating devices must agree on the rules. Once the rules are established, the data transfer phase begins. Connection termination occurs when the session is complete, and communication ends gracefully.
In practice, Session Layer is often combined with the Transport Layer.
Layer 6. Presentation Layer
The position of Presentation Layer in seven layered Open Systems Interconnection (OSI) model is just below the Application Layer. When the presentation layer receives data from the application layer, to be sent over the network, it makes sure that the data is in the proper format. If it is not, the presentation layer converts the data to the proper format. On the other side of communication, when the presentation layer receives network data from the session layer, it makes sure that the data is in the proper format and once again converts it if it is not.
Formatting functions at the presentation layer may include compression, encryption, and ensuring that the character code set (ASCII, Unicode, EBCDIC (Extended Binary Coded Decimal Interchange Code, which is used in IBM servers) etc) can be interpreted on the other side.
For example, if we select to compress the data from a network application that we are using, the Application Layer will pass that request to the Presentation Layer, but it will be the Presentation Layer that does the compression.
Layer 7. Application Layer
The Application Layer the seventh layer in OSI network model. Application Layer is the top-most layer of the seven layered Open Systems Interconnection (OSI) network model. Real traffic data will be often generated from the Application Layer. This may be a web request generated from HTTP protocol, a command from telnet protocol, a file download request from FTP protocol etc.
In this lesson (Seven Layers of Open Systems Interconnection (OSI) Model), you have learned what are the Seven Layers of Open Systems Interconnection (OSI) Model and the functions of these seven layers. The top-most layer of the Seven Layers of Open Systems Interconnection (OSI) Model is the Application Layer and the bottom-most layer of the Seven Layers of Open Systems Interconnection (OSI) Model is Physical Layer. Click "Next" to Continue.

Q5. Transaction processing systems are cross-functional information systems that processdata resulting from the occurrence of business transactions. Explain the differencebetween online processing and batch processing and give one example for each one.
Batchprocessing,where transaction data are accumulated over a periodof time and processed periodically.
Real-time processing (also called onlineprocessing), where data are processed immediately after a transaction occurs. All online transaction processing systems incorporate real-time processing capabilities.

Ex .Point-of-sale (POS) systems at many retail stores use electronic cash register terminals to capture and transmit sales data electronically over telecommunications links to regional computer centers for immediate (real-time) or nightly (batch) processing.