SSD 2 Introduction to computer systems Khamitov

SSD 2 : Introduction to computer systems Khamitov Alim Nadimovich alikhamt@umail. iu. edu

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Lecture 11. Local and Wide Area Networks Communication Strategies Client-Server Framework Peer-to-Peer Networking 3

Local and Wide Area Networks (continued) A network interface card (NIC) is the key hardware component for connecting a computer to a local area network. Different networks use different NICs. Popular network types include Ethernet and Token Ring. 4

Topology Shape of Local-Area Networks (LAN) 5

Network Types Ethernet - a local-area network (LAN) architecture developed by Xerox Corporation Uses a bus or star topology and supports data transfer rates of 10 Mbps. Fast Ethernet - 100 Mbps. Gigabit Ethernet supports data rates of 1 gigabit (1, 000 megabits) per second. 6

Bus topology 7

Star Topology 8

Ring Topology 9

Cable Media Twisted Pair A type of cable that consists of two independently insulated wires twisted around one another. One wire carries the signal while the other wire is grounded and absorbs signal interference UTP (unshielded twisted pair) STP (shielded twisted pair) Looks similar to telephone cable Uses square plastic RJ-45 connector 10

UTP vs STP 11

Cable Media (continued) Coaxial cable A type of wire that consists of a center wire surrounded by insulation and then a grounded shield of braided wire. The shield minimizes electrical and radio frequency interference. Resembles cable-TV cable Uses round, silver BNC connector 12

Wireless Networks Wireless networks use radio or infrared signals to transmit data from one network device to another. handy in environments where wiring is difficult to install provide mobility good for temporary installations Types: - Wireless Personal Area Network - Wireless Local Area Network - Wireless Metropolitan Area Networks (several wireless LANs) - Wireless wide area networks 13

Network Hub Cable from a workstation NIC connects to a network hub, a device that joins communication lines together. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports. When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets. 14

Network Switch a device that filters and forwards packets between LAN segments 15

Hub vs Switch 16

Network Servers Types of servers A file server is a computer and storage device dedicated to storing files. Any user on the network can store files on the server. Dedicated file server: Non-dedicated file server: 17

Dedicated file server delivers programs and data files to workstations. ▪ does not process data or run programs for workstations. 18

Non-dedicated file server computer on a network that performs a dual role as both file server and workstation ▪ also called peer-to-peer capability 19

Application Server Application server - computer that runs a specific application software package also referred to as client/server architecture An application server splits processing between the workstation (client) and the network (server). Network Servers 20

Application Server An application server typically runs database software and performs database functions as requested by the workstations. 21

Print Server Print server: receives files from workstations and forwards them to a specific network printer manages a print queue, a holding area for files waiting to be printed A print job is a file that has been sent to a print queue. 22

Print Server 23

Print Server 24

Server of terminals all processing takes place on the host terminals only display results of processing also known as a time-sharing system Terminal emulation software connects a microcomputer to a host 25

Network Operating System Today’s computers include software necessary to communicate with a network. The software handles the communication between your workstation and the network server. Network operating systems have two components network server software network client software 26

Network Operating System (continued) Network operating system (NOS) software manages network resources controls flow of data maintains security tracks user accounts 27

Network Operating System (continued) Network server software (installed on file server) controls file access from the server’s hard disk manages print queue tracks user data IDs and passwords 28

Network Operating System (continued) Network client software (installed on workstation) gathers login information directs printouts to network printer The server and client software components do not have to match. Many desktop operating systems have some server capabilities. 29

Software Licenses for Networks Using a single-user license for multiple users typically violates software’s copyright. Software publishers offer a network license that allow use by multiple users on a network. 30

Network Software Groupware is application software that supports collaborative work by managing (Metcalfe’s law): shared documents intra-group communications scheduling meetings and allocating resources e-mail password protection for documents telephone utilities electronic newsletters file distribution 31

Network Software 32

Network Software (continued) Workflow software - automates the process of electronically routing documents from one person to another in a specified sequence based on a “process-centered model” 33

Groupware vs. Workflow 34

Communication Strategies Client-Server Framework Peer-to-Peer Connectivity 35

Client-Server Framework Client/Server architecture A network architecture in which each computer or process on the network is either a client or a server. Client interacts with both user and server Clients are PCs or workstations on which users run applications. 36

Client-Server Framework (continued) Server accepts requests from clients and performs some service and returns results Servers are powerful computers or processes dedicated to managing disk drives (file servers), printers (print servers), or network traffic (network servers ). 37

Thin and Thick Clients Two terms used in client-server framework are thin client and thick client Thin client does relatively little work (processing) typically providing little more than a user interface Thick client carries out a substantial portion of the overall work of the system 38

Client Machines Accessing Web Servers Network or Web server Client 39 Client

Peer-to-Peer Connectivity Every member of a peer-to-peer network can communicate with any other member Since peer-to-peer distribute processing, there are less potential communication bottlenecks 40

The 10 Commandments of. . Netiquette

What is Netiquette? Network etiquette (commonly known as netiquette) is the ‘golden rules’ or do’s and don’ts of online communication. Proper manners are as important online as they are offline.

5 The 10 Commandments

The Golden *Human* Rule 1 Treat others as you would like them to treat you esp R ful ect This is still a classroom environment – ‘Group Norms’ apply!

Take out the heat. Recognise that it’s OK to have a different opinion to yours. 2 No flaming

C 3 Copyright Respect OTHER PEOPLE’S WORK Information sharing is wonderful but only take credit for your own work!

There are other ways to express your emotion 4 4 Don’t SHOUT

5 CULTIVATE HEALTHY RELATIONSHIPS Participate in discussions and forums, share information with others and get to know your class mates.

6 Be Honest y t s yi H o t es n th s be e c oli p

7 Be brief and Keep it simple. Write what you would be happy to show your kids, mum or boss!!! Watch spelling and grammar, use of jargons, and acronyms.

Do YOUR Research Kee Fac p it Tru tua e l

CO PR NF IVA ID C Y EN A TI ND AL IT Y Don’t forward sensitive information to others without the writer’s permission

10 SEE others view We are all learners, be patient not everyone has the same level of experience or technology!

10 llo w th en es e jo y y sim pl no ou m r e- e co at te lear mm rw n in an he g re ex dme yo pe nt rie s a u ar e. nce nd Fo co m m an dm en ts

End of lecture 11 thanks for your attention! 55