1. Ministry of Communications and Information Technology Information Technology Institute Network Fundamentals Introduction to Internet Lec2

2. What is the Internet?  Internet Origin and History  Who Owns the Internet?  Internet Connections

3. Internet development in Egypt:  historical background  1993 via a 9.6K link between the Egyptian Universities Network and France  1994 the Egyptian domain was divided into three major subdomains  sci.eg  com.eg  gov.eg  Provide 64K digital access to France

4. Internet Gateway in Egypt

5. Who owns the Internet?  No one actually owns the Internet  Many Orgs, ISPs, Companies, Govs own pieces of Internet Infrastructure.  But many organization oversee.  ISOC Internet Society  IETF Internet Engineering Task Force

6. Network Communicating Protocols

7. The Need for Protocols  Protocols are needed for computer networks to communicate efficiently  Network protocols are set of rules that enable data to flow from one NIC to another  Protocols control the messages origination, the messages end, and the messages quantity in the network.

8. Major Networking Protocols  NetBEUI  IPX/SPX  TCP/IP  AppleTalk

9. NetBIOS  Network Basic Input/Output System.  A common network protocol that allows applications on different computers to communicate within a local area network (LAN).  It was created by IBM for its early PC Network, and was adopted by Microsoft.  It does not support a routing mechanism.  NetBIOS was later formalized in NetBEUI.

10. NetBEUI  NetBIOS Extended User Interface.  This is an enhanced version of the NetBIOS protocol used by network operating systems (NOS), such as Microsoft's Windows NT.  NetBEUI was developed by IBM for its LAN Manager product and has been adopted by Microsoft for its Windows NT, LAN Manager, and Windows for Workgroups products.  Non-routable

11. NetBEUI Advantages and Disadvantages  Advantages  High speed on small networks  ease of implementation  small memory overhead  Self tuned (does not need configuration)  Disadvantages  It cannot be routed between networks.

12. IPX/SPX  Internet Packet Exchange Sequenced Packet Exchange.  A communications protocol devised by Novell for Novell NetWare.  IPX/SPX packets can be routed from one network to another

13. IPX/SPX Advantages and Disadvantages  Advantages  Ease of setup.  Support for routing between networks.  Speeds greater than TCP/IP for NT.  Disadvantages  Slower than NetBEUI.  IPX/SPX is not a vendor neutral

14. TCP/IP  Transmission Control Protocol/Internet Protocol.  TCP/IP is open standard protocol  Not tied to one vendor  TCP/IP is the internet protocol  Now internet use TCP/IP v4  Next version TCP/IP v6  It is the default protocol for  Windows NT4  Windows 2000  UNIX

15. TCP/IP Advantages and Disadvantages  Advantages  Broad connectivity among all types of computers and servers  Direct access to the Internet  Disadvantages  Difficulty of setup  Slower than IPX & NetBEUI

16. AppleTalk  AppleTalk is a set of local area network communication protocols originally created for Apple computers. An AppleTalk network can support up to 32 devices and data can be exchanged at a speed of 230.4 kilobits per second (Kbps).

17. OSI Reference Model  OSI: Open Systems Interconnection  The OSI model is the primary architectural model for networks.  It describes how data and network information are communicated from an application on one computer, through the network media, to an application on another computer.  The model was defined by the International Organization for Standardization (ISO)  The OSI reference model breaks this approach into layers.

18. Advantages of Reference Models  It divides the network communication process into smaller and simpler components, thus aiding component development, design, and troubleshooting.  It allows multiple-vendor development through standardization of network components.  It encourages industry standardization by defining what functions occur at each layer of the model.  It allows various types of network hardware and software to communicate.  It prevents changes in one layer from affecting other layers, so it does not hamper development.

19. OSI Seven Layers  Application  Presentation  Session  Transport  Network  Data Link  Physical

20. What should I send?  End-user Interface  Where client applications reside  Displays received information  Sends user’s data to lower layers Application Layer

21. Presentation Layer  The presentation layer is responsible for the delivery and formatting of information to the application layer for further processing or display.  It relieves the application layer of concern regarding syntactical differences in data representation within the end-user systems.  An example of a presentation service would be the conversion of an EBCDIC-coded text file to an ASCII- coded file.

22. Close Connection You are welcome! Thank you. I would like to send you something. Sounds good! Establish Connection Controls the sessions between the local and remote applications Session Layer

23. Transport Layer  There is services that can be optionally provided at this layer:  Connection-Oriented  Same Order Delivery  The simplest way of doing this is to give each packet a number, and allow the receiver to reorder the packets.  Reliable Data  Flow Control  Without flow control a computer might be flooded with so much information that it can't hold it all before dealing with it.

24. Network Layer  Organize data into datagrams (packets)  Addresses messages  Routing  Provides the functional and procedural means of transferring variable length data sequences from a source to a destination via one or more networks

25. Data Link Layer  Reliable data transfer across a physical link  It provides the means to detect errors that may occur in the Physical layer.  Organize the data into frames, to be put on the physical medium  Transfers data between adjacent network nodes  The data link layer is split into MAC and LLC sublayers

26. Physical Layer  The Physical layer defines all the electrical and physical specifications for devices.  The physical layer is the most basic network layer, providing only the means of transmitting raw bits.

27. The Internet Protocol TCP/IP Protocol Suite

28.  Specified and extensively used before the OSI model  Developed by research funded US Department of Defense  Used by the Internet

29. TCP/IP Protocol Suite

30. Addressing

31. Layers and Addresses in TCP/IP

32. Physical addresses

33. IP addresses

34. Port addresses

35. Where do I go? Provides physical routing information Network Layer Addressing

36. IP Address 255 Dotted Decimal Maximum NetworkHost 32 Bits

37. IP Addressing 255 Dotted Decimal Maximum NetworkHost 128 64 32 16 8 4 2 1 11111111 Binary 32 Bits 18916 17 242532 128 64 32 16 8 4 2 1

38. Decimal Equivalents of Bit Patterns 00000000=0 10000000=128 11000000=192 11100000=224 11110000=240 11111000=248 11111100=252 11111110=254 11111111=255 128 6432168421

39. IP Address Classes  Class A:  Class B:  Class C:  Class D: Multicast  Class E: Research Network Host Network Host Network Host 8 Bits

40. IP Address Classes 1 Class A: Bits: 0NNNNNNN Host 891617242532 Range (1-126) 1 Class B: Bits: 10NNNNNN Network Host 891617242532 Range (128-191) 1 Class C: Bits: 110NNNNN Network Host 891617242532 Range (192-223) 1 Class D: Bits: 1110MMMM Multicast Group 89 16 17242532 Range (224-239) Network Multicast Group

41. Thank you