HOMEWORK

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1.What are the three main factor you must consider when selecting a product or technogy? what are the three major considerations within the cost factor? Which usally wins-the best technogy that does what user need?
1.Total purchase cost for all hardware and software Typically,"base price" are only a fraction of total cost
2.Labor costs to plan,install often greatly outweigh product purchase cost
3.Life cycal costs form initial purchase to finalabandonment
1.Performance
2.Feasibility
3.Cost
User need
1.Drive everything else
2.Must communicate with user to understand their need
3.Must support important user needs without bankrupting the firm

2.Give the exact definition of standard.(See Page4.)What benefits do standards bring?
"standard" are rules of operation that are followed by most or all vendors.
Standard bring many benefits.
-If there are good standards in an area,you do not have to buy all your products form a single company.
-Being able to buy form multiple vendors the benefits of competition,including lower prices and feauter-rich products.
-You do not have to worry if one of your key vendors fails behind the pace of development.

3.Give the exact definifition of network .(See Page5.) Why does the fact you only need to know the receiving computer's address make life simpler?
"network" is a collection of computers that are interconnected so that any computer can send messages to any other compu ter simply by giving the receiver's network and dress at the start of the message.

4.Does network mean the same thing as the Internet?Explain. Why do we have inter in the name Internet?
Yes.Internet consists of thousands of network scattered aroud the qlobe.
Because universities, coorrations and other organizations often own individual network.

5.What is the function of a router? What is a route?
"router" is connect the internet's network. Then cooperate to give an end to end route for each packet.
"route" is the path of your packet hops form one router to another ,across mutiple networks,untill it eventually reachs the destination computer.

6.What are the two type of address on the Internet?
1.Internet address have four number segment separated by dot.
2.Host name consist of several label of text separated by dot.

7.Is a webserver on the Internet a host computer? Is a home PC on the Internet a host computer?
-Yes,websever is on the internet a host computer.
-Yes,a home PC is on the internet a host computer.

8.Name the five layers in the hybrid TCP/IP-OSI architecture.Give the exact definition of each.(See Page10-12.) What standard or standards are used at each layer when you access the World Wide Web from home? What is a frame? What is a packet?
1.Application Layer standards allow two application programs to work together,even if they come from different vendor. Application layer is the HTTP(Hyper Text Transfer Protocol) standard.
2.Transport Layer standards allow two computers to exchange messages even if they come form different platform type.Transport layer is the Transmission Control Protocol(TCP) standard.
3.Internet Layer standards allow packets to be routed accross multiple routers form a source host to a destinationhost,even if the routers come form difference vendor.Internet layer is the Internet Protocol(IP) standard.
4.Data Link Layer standard organize transmissions into collection of bits called frames and message the transmisions of these frames within a single network.Data link layer is the Point-to-Point Protocol(PPP) standard.
5.Physical Layer standardizes connector plug,transmission media,electrical sigaling,and other physical matters you can see and touch,even if the components come form different vendor.
"Packet" refer to Internet layer standards are concerned with end-to-end routing of messages acorss multiple subnets
"Frame" refer to Subnet standards are concerned with routing messages within single networks(subnet).

9.Give the exact definition of protocal .(See Page10.)Are all standards protocols?
"Protocol" standard to goven communication between peer processes at the same layer on different system.
Yes,they are.

10.Distinguish between subnet and internet transmission.
-Internet layer provides routing across multiple subnets.But subnet layer standards (data link and physical) provide for transmission within a single network.
-Route from beginning to end(like internet layer).For different part,may travel by car,airplane,or boat(like subnet layer).

11.What is platform independence? Standard at which layer bring platform independance?
"Platform indenpendence" refer to two computers don't have to be of the same platform type.
TCP/IP standard bring platform independence.

12.Distinguish between file server program access and client/server processing in terms of where processing is done,the implications for program functionality,scalability,user interface richness,and platform independence. For file server program access,explain why you cannot simply say "processing is done on the PC." What program runs on application server?
Response Time
-File Server Program Access( Very good); uses local PC processing power
-Client/Server Processing (Very good); local PC processing power for user interface But retrivals from the server can
cause delays.
Program Functionality (Size)
- File Server Program Access (Poor); many client PCs are small
-Client/Server processing( good ) ;not limited to client PC processing power, Heavy work can be done on ther sever machine
Scalability
-File Server Program Access (poor); client PC sizes are limited
-Client/Server Processing(Very good); platform independence allows servers to be larger than PCs
to grow, leave client machine ther same, increase the size of the server machine.
Platform Independence
-File Server Program Access (poor) ;only works with PC clients and Pc file servers OK for word processing etc.
-Client/Server Processing(excellent); use any server you want, also any client
"Cient Program"runs on the client PC
"Server program" runs on the server

13.Which is scalability? Why is it need? What is the link between platform independence and scalablity?
Scalability refer to: The ability to grow to much large sizes without changing an application
Server scalability is critical to corporation, and ther platform independent nature of client/server processing creates a high degree of scalability by allowing a broad range of server technologies to be used.

14.Distinguish between LANs,site network,and enterprise networks .Distinguish between WANs and enterprise networks.
LANs is small networks, consisting of only a few machines in a single office or small company.
Site network links the various Lans that exist within a single site, connect a few LANs within a single building.
Enterprise network is use the services of transmission carriers
WANs carry traffic only between sites, whereas enterprise networks also include the site networks at ther connected sites.

15.Where is the processing done in terminal-host systems? What are the implecations of your answer for respone time and rich graphic?
Terminal-host systems(poor); Relies on distant hosts. Long delays if overloaded. Some sutems use smart terminals with limited editing capability to reduce response time for simple editing tasks only

16.What is downsizing? What is legacy application? Why is it impossible to downsize all host legacy applications in two or three years?
Downsizing refer to: move application form terminal- host systems to PC network.
Legacy Application refer to: Result of this gradual abandonment of terminal-host systems
because budgets are always limited,so the conversion of legacy systems can not take place overnight every organization has a mixture of new systems and legacy systems.

17.Distinguish between standard PCs and workstations in terms of processing power.Do PC networks and workststion networks both use client machines and server machines?
Workstation found themselves limited to specialized areas needing higher comput power than PCs could provide.
Yes, they do.

18.Distinguish between standards architectures and individual standards. What are the four major standards architecture? Why has TCP/IP emerged as the predominant standards architectrue? In what situations are OIS, SNA, and IPX/SPX important?
- Different use conditions might require different standards.
- New standards are developed to talk advantage of technolgical advances.
- Although it is sad to say, battles in standards comintees often result in two or more standrds that do almost the same thing.
The four major standards architecture are Application, Transport, Internet, Subnet.
Because TCP/IP standareds tend to be inexpensive and quick to market. This makes them very attractive and in fact has made them dominant in the marketplace alove the subnet layers.
OSI ;open systems are those that are open to communicating with all other systems.
-ISO (International Organization for Standardization) ;Traditional standards agency for industrial procucts.
-ITU-T ( International Telecommunications Union-Telecommunications Standards Sector); Traditional standards agency for telecommunications.
SNA ; (Systems Network Architecture)
Control by IBM . IBM shares specifications, so most mainframe systems from all vendors use SNA or a variant. Still accounts for avery large part of long-distance data traffic.
IPX/SPX(Created by Novell)
So IPX/SPX is till widely used in PC networking with Novell Netware servers. Even Novell is switching to TCP/IP, many PC networks have not converted their Novell servers and clients to TCP/IP. Must be considered in PC networking.