sem 5 CN

computer network is system in which multiple computer devices are connected to each other to share information and resources 

LAN- local area network is computer network that interconnects computer devices within limited area such as school, laboratery .

Man- metropolitan area like city .

wan- large scale geographical area.

protocol- is set of rules to govern data communication 

OSI MODEL= OSI stands for Open System Interconnection is a reference model that describes how information from a software application in one computer moves through a physical medium to the software application in another computer.

Internet - is type of world wide computer network 

internet is computer network that interconnects hundreds of millions of computer devices throughout the world

 WEB-  Web page consist of objects .

• object can be HTML file,text file, audio file etc..
• if webpage consist of HTML text and five images then web page has 6 objects.

• A web page is given an online address called a Uniform Resource Locator (URL). A particular collection of web pages that belong to a specific URL is called a website, e.g., www.facebook.com, www.google.com, etc. So, the World Wide Web is like a huge electronic book whose pages are stored on multiple servers across the world.

HTTP

HTTP stands for HyperText Transfer Protocol.

HTTP Is Web's application layer protocol 

it defines how web client requests web pages from web server and how server transfer web page to client.

When user request for web page , browser sends HTTP request massage to server

server receive request and sends response with HTTP request massage.

HTTP uses TCP as its underlying transport layer protocol.

HTTP is a stateless protocol i.e. server maintains no information about past client reque

HTTP follows client/server model

-client- browser that request,receives,and displays web object.

-server -web server sends object in response to the server.

Connectionless protocol: HTTP is a connectionless protocol. HTTP client initiates a request and waits for a response from the server. When the server receives the request, the server processes the request and sends back the response to the HTTP client after which the client disconnects the connection. The connection between client and server exist only during the current request and response time only.

Two Types

-non persistent HTTP 

-persistent HTTP 

Non Persistent HTTP

• non persistent connection is closed after the server sends the requested object to the client.
• connection is used axactly for one request and one response.
• for downloading multiple objects it required multiple connections .
• non persistent connection are default mode for HTTP/1.0
• refer darshan pdf

persistent in pdf