1. NETWORKING CONCEPTS

2. CLASSIFICATION OF NETWORKS 2 primary categories determined by size LAN WAN

3. LAN Usually privately owned Links the device in a single office,building or campus LAN size limited to few kilometers Designed to allow resources to be shared between personal computers or work stations The resources can be h/w(eg:printer),s/w or data

4. LAN Eg of LAN found in many bussiness environment links a work group of task related computers Eg. Engineering workstations or accounting PC One computer may give large capacity disk drive and may become server to client s/w are saved in this server and used by whole group Here size of LAN is determined by licensing restrictions on no of users licensed to access the OS

5. LAN LAN are distinguished from other type of n/w by their transmission media and topology Common LAN topologies are Bus,Ring,Star Earlier LAN have data rates of 4 to 16 Mbps Today it ranges from 100 to 1000 Mbps

6. Figure 1.10 An isolated IAN connecting 12 computers to a hub in a closet

7. WAN

10. Provides long distance transmission of data,image,audio& video information over large geographic area that may be a country,continent,or whole world A WAN can be as simple as a dial up line that connect a home computer to internet.this is point to point WAN

11. WAN A swithced WAN usually connects end systems which comprise a router,(internetworking connecting device) that connects to other LAN or WAN This type of WAN is often used to provide internet access

12. WANs: a switched WAN v. a point- to-point WAN

13. WAN Early eg of switched WAN is X.25 X.25 is designed to provide connectivity b/w end users X.25 is replaced by frame relay Another eg of switched WAN is ATM(Asynchronous Transfer mode) WAN contains a large collection of machines for running user programs These machines are called hosts

14. WAN Hosts are connected by communication subnet or subnet Subnet is owned and operated by ISP Subnet carries messages from host to host Components of subnet Transmission lines Switching elements

15. WAN Transmission Lines Move bits between machines.They can be copperwire,optical fibre etc Switching Elements Specialised systems that connects 3 or more transmission lines.these switching elements are known as routers When data arriving on incoming line the switching element must chose an outgoing line on which to forward them

16. Relation b/w host on LAN’s and subnet

17. WAN In fig each host connect to a LAN on which a router is present The collection of communication lines and routers(not host) form subnet Store and forward subnet/Packet switched subnet When routers are not connected directly and they wish to communicate,when that packet is sent from one router to other through intermediate router,the packet is received and stored at the router until entire output line is free and then forwarded.that is packet switched subnet

18. MAN n/w with a size b/w LAN and WAN Covers an area inside a town or city Eg.cable TV n/w for TV transmission but today can also be used for high speed data connection to internet

19. Interconnection of Networks: Internetwork When two or more networks are connected, they become an internetwork, or internet

21. Metropolitan Area Networks A metropolitan area network (MAN) is a network with a size between a LAN and a WAN. It normally covers the area inside a town or a city. It is designed for customers who need a high-speed connectivity, normally to the Internet, and have endpoints spread over a city or part of city. A good example of a MAN is the part of the telephone company network that can provide a high-speed DSL line to the customer.

22. THE INTERNET The Internet is a structured, organized system. An internet (note the lowercase letter i) is two or more networks that can communicate with each other. The most notable internet is called the Internet (uppercase letter I), a collaboration of more than hundreds of thousands of interconnected network. It is made up of many wide- and local-area networks joined by connecting devices and switching stations.

23. ISPs International Internet Service Providers National Internet Service Providers Regional Internet Service Providers Local Internet Service Providers

24. International Internet Service Providers At the top of the hierarchy are the international service providers that connect nations together. National Internet Service Providers The national Internet service providers are backbone networks created and maintained by specialized companies. Example:SprintLink, PSINet, UUNet Technology, AGIS, and internet Mel To provide connectivity between the end users, these backbone networks are connected by complex switching stations (normally run by a third party) called network access points (NAPs).

25. Regional Internet Service Providers Regional internet service providers or regional ISPs are smaller ISPs that are connected to one or more national ISPs. Local Internet Service Providers Local Internet service providers provide direct service to the end users. The local ISPs can be connected to regional ISPs or directly to national ISPs. Most end users are connected to the local ISPs.