1. Computer Networks part II 1

2. Network Types Defined Local area networks Metropolitan area networks Wide area networks 2

3. Local Area Network (LAN) Series of interconnected computers, printing devices, and other computer equipment that share hardware and software resources Service area usually limited to a given office area, floor, or building 3

4. Example of a LAN 4

5. Metropolitan Area Network Links multiple LANs in a large city or metropolitan region Typically uses fiber-optic connections 5

6. Example of a MAN 6

7. Wide Area Network (WAN) Far-reaching system of networks that usually extends over 30 miles and often reaches across states and continents 7

8. 8 Types of Networks Internet A wide area network that spans the planet So, who owns the Internet?

9. 9 Internet Connections Internet backbone A set of high-speed networks that carry Internet traffic, provided by companies such as AT&T, Verizon, GTE, British Telecom, and IBM Internet service provider (ISP) A company that provides other companies or individuals with access to the Internet

10. Identifying a Network Type Communications medium – Wire cable, fiber-optic cable, radio waves, microwaves Protocol – How networked data is formatted into discrete units – How each unit is transmitted and interpreted Topology – Physical layout of cable and logical path Network type – Private versus public 10

11. Enterprise Network Enterprise network – Combination of LANs, MANs, or WANs that provides users with an array of computer and network resources to complete different tasks 11

12. Enterprise Network 12

13. Enterprise-Wide Topologies Enterprise – An entire organization Backbone networks – Serial backbone – Distributed backbone – Collapsed backbone – Parallel backbone 13

14. Enterprise-Wide Topologies Serial backbone Two or more hubs connected to each other by a single cable Distributed backbone Hubs connected to a series of central hubs or routers in a hierarchy A simple distributed backbone network 14

15. Enterprise-Wide Topologies A distributed backbone connecting multiple LANs VA GANC 15

16. Enterprise-Wide Topologies Collapsed backbone Uses a router or switch as the single central connection point for multiple subnetworks A collapsed backbone network 16

17. Enterprise-Wide Topologies Parallel Backbone Collapsed backbone arrangement that consists of more than one connection from central router or switch to each network segment A parallel backbone network 17

18. Enterprise-Wide Topologies Mesh networks Routers are interconnected with other routers, with at least two pathways connecting each router An example of a mesh network 18

19. Wide Area Network (WAN) Topologies Peer-to-peer topology WAN with single interconnection points for each location Dedicated circuits Continuous physical or logical connections between two access points that are leased from a communication provider A peer-to-peer WAN 19

20. Wide Area Network (WAN) Topologies Ring WAN topology Each site is connected to two other sites so that entire WAN forms a ring pattern A ring-configured WAN 20

21. Wide Area Network (WAN) Topologies Star WAN topology Single site acts as the central connection point for several other points A star-configured WAN 21

22. Wide Area Network (WAN) Topologies Mesh WAN topology Many directly interconnected locations forming a complex mesh Full-mesh and partial-mesh WANs 22

23. Wide Area Network (WAN) Topologies Tiered WAN topology Sites connected in star or ring formations are interconnected at different levels, with interconnection points organized into layers A tiered WAN topology 23

24. Logical Topologies Refers to the way in which data are transmitted between nodes Describes the way: – Data are packaged in frames – Electrical pulses are sent over network’s physical media Logical topology may also be called network transport system 24

25. 25 Network Architecture Defines how network functions at a logical level Two primary types – Client-server – Peer-to-peer (P2P)

26. 26 Client-server Network Architecture Nodes are either clients or servers Clients use services Servers provide services – Access to shared data – E-mail – Printing – FAX Client software on client node cooperates with server software on server node – WWW is largest client server application

27. 27 Peer-to-Peer Network Architecture All nodes on the network are equal. Any node can be both a client and a server. Napster was an example of a P2P network used to share MP3 files. Windows printer and file sharing use P2P.

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