How to use the Internet

Ikjun Yeom

How to send a packet buy a computer make sure that the computer is equipped with a network inter-

face card find a place where the computer can be hooked up to the Inter-

net configure network setting properly write a client-server program for sending and receiving a packet run your server program on the destination run your client program to send a packet

Network Settings

IP address– can be configured manually– or can be configured automatically by

DHCP subnet mask default gateway DNS server

Sample Code - Server

Sample Code - Server

Sample Code - Client

Sample Code - Client

How does a packet reach to a destination in the Internet?

Internet

ISP ISP ISP

IAPIAP IAP IAP IAP IAP

Name Resolution

URL to IP address Using Domain Name Service

Top Do-

main

.kr .com .net

.ac.kr .co.kr

.skku.ac.kr

.naver.com

Subnet

DefaultGateway

Address Resolution

mapping an IP with a MAC address ARP (Address Resolution Protocol)

Routing

Intra-domain routing– RIP– IGRP– OSPF

Inter-domain routing– BGP• iBGP• eBGP