open system interconnection, Exams of Computer science

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E - Commerce

Muhammad Kamran

Lecture 2

What is a network?

1. A network can be anything from a simple collection of computers at one location connected through a connectivity media to the internet (a global network of networks)
2. Local Area Network (LAN) is a server-based network confined to a particular area/place
3. Most LANs consist of many clients and a few servers

2. 4

2121 LAYERED TASKSLAYERED TASKS

We use the concept of We use the concept of layerslayers in our daily life. As anin our daily life. As an example, example, letlet usus considerconsider twotwo friendsfriends whowho communicate through postal mail. The process of communicate through postal mail. The process of sending a letter to a friend would be complex if there sending a letter to a friend would be complex if there were no services available from the post office. were no services available from the post office.

2. 5 Figure 2.1 Tasks involved in sending a letter

2. 7 OSI Network Model

ISO OSI model

Application layer Presentation layer Session layer Transport layer Network layer Data link layer Physical layer Application layer Presentation layer Session layer Transport layer Network layer Data link layer Physical layer Sender Side Receiver Side

TCP/IP Stack Mapped To OSI Model

OSI Model TCP/IP Stack

Application Presentation Session Transport Network Data Link Physical Telnet HTTP SMTP FTP TCP UDP IP RIP ARP Network Interface Card Drivers

TCP/IP Protocol Stack

Members

HTTP Used for web page requests Telnet Terminal Emulation Protocol – connects a local computer with a remote computer FTP File Transfer Protocol - provides an interface and services for file transfer over the network – upload from local to remote & vice versa SMTP Simple Mail Transport Protocol – provides e-mail services on the internet TCP Transmission Control Protocol – connection-oriented transport protocol UDP User Datagram Protocol – connectionless transport protocol IP Internet Protocol – provides basis for IP addressing on the network ARP Address Resolution Protocol – maps IP address to MAC hardware address RIP Routing Information Protocol – Routing protocol used by routers to determine the best path for packets on the network