Introduction to Networking ITNW 1325, Chapter I

1. Introduction to Networking ITNW 1325, Chapter I

2. Computer Networks Overview: • Original purpose – to enable data communications between computers and computerized devices • Secondary purpose – to provide reliable high-speed channels for data exchange • Newer purpose – to provide secure communication channels maintaining reliability and high data rates • Oldest approach – copy data to temporary media and physically carry it between computers (sneakernet) • Later approach – connect small number of very large stationary mainframe computers together using cables

3. Computer Networks Overview (continued): • Traditional approach – connect many small stationary personal computers together using cables • Modern approach – connect small portable computers, personal electronic devices, and personal computers using cables or wireless media • Advantage – enable transfer of digital information without copying it to intermediate storage media • Advantage – enable sharing of data and peripheral devices between multiple users

4. Computer Networks Overview (continued): • Advantage – enable centralized administration of many computers increasing productivity and security • Disadvantage – impose increasing requirements onto technical personnel’s skills and qualifications • Disadvantage – carry potential security issues requiring secure implementation and constant monitoring

5. Network Models

6. Network Models Peer-to-Peer (“Workgroup”): • Implies two or more computers with modest processing power and equal authority • Enables every computer to send and receive data directly to and from any other computer • Implies no centralized administration – end users are responsible for controlling access to their resources • Advantages – requires simple configuration only and carries reduced setup and maintenance costs • Disadvantage – decentralized administration complicates management as network grows in size

7. Network Models Peer-to-Peer (continued): • Disadvantage – decentralized security simplifies unauthorized access to shared resources • Suitable only for small networks when security and growth are not critical • Newer networks – enable file sharing over the Internet, free or not free of charge (Napster, Freenet, BitTorrent)

8. Network Models Peer-to-Peer (continued):

9. Network Models Client/Server: • Implies presence of a server – a dedicated computer that controls communications between others • Implements centralized security – servers control and secure sharing of data, devices, and storage space • Servers possess substantial processing power – use advanced hardware (CPU, memory, storage, etc.) • Servers benefit from using redundant and hot swap hardware for reliability – minimizes downtime • Servers require placement, environmental, and security control by specially trained technical personnel

10. Network Models Client/Server (continued): • Servers are very expensive and require special network operating systems (NOS) to enable communication, security, and distribution of data and applications • A NOS is expensive – licensed per user – and requires deep expertise and high credentials for handling • Commonly used NOS – Windows Server 2008/2003, Mac OS X Server, Linux versions, SUN Solaris, etc. • Clients are regular workstations carry general-use operating systems (Windows 7/XP, etc) – connect to the server for permission to access shared resources

11. Network Models Client/Server (continued):

12. Network Models Client/Server (continued): • Advantage – centralized security management minimizes chances for unauthorized access to resources • Advantage – simplifies administration of large and growing networks due to improved scalability • Advantage – enables monitoring, diagnostics, and troubleshooting the network from one location • Advantage – use of powerful servers that are optimized for heavy processing loads improves responsiveness • Advantage – offers extensive protections via security policies, logging, network authentication, etc.

13. Network Models Client/Server (continued): • Disadvantage – requires substantial planning as well as set up and maintenance costs and time • Disadvantage – requires personnel with much higher high technical expertise

14. Network Classes

15. Network Classes Overview: • Reflect the size of the network – larger classes employ wider variety of network technologies and media • Local Area Networks (LANs) – connect computers within the same building or few small buildings • Metropolitan Area Networks (MANs) – connect LANs within boundaries of a city, area, or large organization • Wide Area Networks (WANs) – connect remote LANs/MANs via common telecommunication carriers • MANs are often referred to as WANs – with Internet being the largest WAN

16. Common Networking Terms

17. Common Networking Terms Overview: • Connectivity Device – a device that connects multiple networks or parts of the same network • Host – a computer or a connectivity device that participates in communications over the network • Protocol – a standard set of communication rules between hosts (analogous to a human language) • Network Address – a unique number that identifies a host within the computer network • Topology – a physical or logical layout of a network, that is dependent on the technology employed

18. Common Networking Terms Overview (continued): • Physical Segment – a group of hosts that share the same transmission medium • Data Units – chunks the data stream is broken into for increased efficiency and reliability of communication

19. Common Networking Terms Bus Topology:

20. Common Networking Terms Ring Topology:

21. Common Networking Terms Star Topology:

22. Common Networking Terms Hybrid Topology:

23. Network Functions

24. Network Functions Internet: • Enables access to Internet resources, such as Web pages, to broad population of users • Provides other services (file transfer, security filters, Internet addressing schemes, remote access via Internet) Email: • Provides communication between employees – proven to improve their effectiveness and satisfaction • Involves mail servers and clients, such as MS Outlook

25. Network Functions Print: • Enables printer sharing across the network while minimizing the number of printers needed and costs • Simplifies printer problem diagnostics and resolution File: • Enables sharing of data files, applications, and network storage space via use of file servers • Makes information exchange effective and secure via centralized management and backups • Reduces the overall administration of files and data

26. Network Functions Communications: • Enables convergence – use of various types of communications services (e-mail, video, telephone, fax, cell phones, etc.) within the same network • Offers unified communications – centralized management of multiple network communications Access: • Enables remote users to login to the network and fully utilize its resources via a remote access server • Allows network users to connect to external machines

27. Network Functions Management: • Split into multiple smaller tasks – with each one as important for the network as others • Traffic Monitoring and Control – regulates data transmission activity, alerts humans about a problem • Load Balancing – distributes data transfers evenly across a network in order to avoid congestion • Address Management – centralizes management and assignment of network addresses • Hardware Diagnosis/Failure Alerts – enables hardware monitoring and automatic e-mail or paging notifications

28. Network Functions Management (continued): • Security Audit – keeps track of security measures enforced and notification about security breaches • Data Backup/Restore – centralizes copying of critical data files from servers to secure locations and retrieving them in case the original files are lost • License Tracking – determines the use of copies of an application within the network, ensuring that the number of available licenses isn’t exceeded

29. Homework • Read the chapter and the summary section, then review the key terms learned • Answer the review questions and verify your answers with the chapter or lecture slides • Complete the hands-on project 1-1 and case projects 1-1 and 1-2