Ministry of Communications and

Information Technology

Information Technology Institute

Information Technology InstituteInformation Technology Institute

Network FundamentalsIntroduction to Internet

Lec2

What is the Internet?

Internet Origin and History Who Owns the Internet? Internet Connections

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

Internet Gateway in Egypt

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

Network Communicating Protocols

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.

Major Networking Protocols

NetBEUI

IPX/SPX

TCP/IP

AppleTalk

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.

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

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.

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

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

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

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

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).

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.

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.

OSI Seven Layers

Application Presentation Session Transport Network Data Link Physical

What should I send?

End-user Interface Where client applications reside Displays received information

Sends user’s data to lower layers

Application Layer

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.

CloseConnection

You arewelcome!

Thank you.I would like to

send yousomething.

Sounds good!

EstablishConnection

Controls the sessions between the local and remote applications

Session Layer

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.

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

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

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.

The Internet Protocol

TCP/IP Protocol Suite

TCP/IP Protocol Suite

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

TCP/IP Protocol Suite

Addressing

Layers and Addresses in TCP/IP

Physical addresses

IP addresses

Port addresses

Where do I go?

Provides physical routing information

Network Layer Addressing

IP Address

255 255 255 255

DottedDecimal

Maximum

Network Host

32 Bits

IP AddressingIP Addressing

255 255 255 255

DottedDecimal

Maximum

Network Host

128 64 32 16 8 4 2 1

11111111 11111111 11111111 11111111Binary

32 Bits

1 8 9 16 17 24 25 32

128 64 32 16 8 4 2 1

128 64 32 16 8 4 2 1

128 64 32 16 8 4 2 1

Decimal Equivalents of Bit PatternsDecimal Equivalents of Bit Patterns

0 0 0 0 0 0 0 0 = 0

1 0 0 0 0 0 0 0 =128

1 1 0 0 0 0 0 0 =192

1 1 1 0 0 0 0 0 =224

1 1 1 1 0 0 0 0 =240

1 1 1 1 1 0 0 0 =248

1 1 1 1 1 1 0 0 =252

1 1 1 1 1 1 1 0 =254

1 1 1 1 1 1 1 1 =255

128 64 32 16 8 4 21

IP Address ClassesIP Address Classes

Class A:

Class B:

Class C:

Class D: Multicast

Class E: Research

NetworkNetwork HostHost HostHost HostHost

NetworkNetwork NetworkNetwork HostHost HostHost

NetworkNetwork NetworkNetwork NetworkNetwork HostHost

8 Bits 8 Bits 8 Bits 8 Bits

IP Address ClassesIP Address Classes1

Class A:

Bits:

0NNNNNNN0NNNNNNN HostHost HostHost HostHost

8 9 16 17 24 25 32

Range (1-126)

1

Class B:Bits:

10NNNNNN10NNNNNN NetworkNetwork HostHost HostHost

8 9 16 17 24 25 32

Range (128-191)1

Class C:Bits:

110NNNNN110NNNNN NetworkNetwork HostHost

8 9 16 17 24 25 32

Range (192-223)1

Class D:Bits:

1110MMMM1110MMMM Multicast GroupMulticast Group Multicast GroupMulticast Group

8 9 16 17 2425 32

Range (224-239)

NetworkNetworkNetworkNetwork NetworkNetworkNetworkNetworkNetworkNetworkNetworkNetwork NetworkNetworkNetworkNetwork

Multicast GroupMulticast Group Multicast GroupMulticast GroupMulticast GroupMulticast Group Multicast GroupMulticast GroupMulticast GroupMulticast Group Multicast GroupMulticast Group

Thank you