internet services, protocols, applications, packets and frames
TRANSCRIPT
INTERNET SERVICES, PROTOCOLS, APPLICATIONS, PACKETS AND FRAMES
CRAMAROSSA GIUSEPPEAPRIL 2015
TOPICS• INTERNET SERVICES• PROTOCOLS• PORTS• PACKETS• FRAMES• ISO/OSI MODEL
COMMUNICATION IN INTERNET• INTERNET SERVICES OR APPLICATION• Mailing lists• E-commerce• File Transfer• WWW• Instant messagging
• USE OF A WIDE VARIETY OF PROTOCOLS
PROTOCOLS• A SET OF PREDEFINED RULES AND SYMBOLS• ADVANTAGES
• Two or more devices from different vendors can communicate each other
• EXAMPLES OF APPLICATION PROTOCOLS• HTTP• FTP• POP3• SMTP• DNS
• SOME OF THEM HAVE A SECURE VERSION• THEY HAVE CLIENT AND SERVER APPLICATIONS• THEY USE ONE OR MORE PORTS
PORTS• NUMBER BETWEEN 0 AND 65535 • IDENTYFIES THE REQUESTED SERIVICE• THERE ARE 3 CATEGORY OF PORTS
• Well-kwown ports 0 - 1023• Registered ports• Dynamic Ports
• EXAMPLES• HTTP: 80• FTP: 20, 21• POP3: 110• SMTP: 25• DNS: 53
SERVER APPLICATIONS• PROVIDES A RESPONSE TO A CLIENT REQUEST• IN A HOST THERE COULD BE ONE OR MORE SERVER
APPLICATIONS• EXAMPLES• HTTP: Apache• FTP: Filezilla • POP3: Mercury Mail• SMTP: Mercury Mail
• THEY USE STATIC PORTS
CLIENT APPLICATIONS• REQUEST A SERVICE TO A SERVER APPLICATION• IN A HOST THERE COULD BE ONE OR MORE CLIENT
APPLICATIONS• EXAMPLES• HTTP: Web Browsers• FTP: Filezilla • POP3: Outlook Express• SMTP: Outlook Express
• THEY USE DYNAMIC PORTS
TRANSPORT PROTOCOLS• APPLICATIONS USE TANSPORT PROTOCOLS IN ORDER TO SEND AND
RECEIVE PACKETS • SOME OF THEM ARE
• TCP• Connection oriented• Reliable• Three-way handshake
• UDP• Connectionless• Unrealible
• HANDLE TWO CONNECTION MODE• Unicast• Multicast
PACKETS AND FRAMES• LAYER 2 OF THE ISO-OSI MODEL HANDLES FRAME• THESE FRAMES ARE FORWARDED BY A SWITCH• BY LAYER 3 OF THE ISO-OSI MODEL, FRAMES BECOMES PACKET• THESE FRAMES ARE FORWARDED BY A ROUTER USING ROUTING
PROTOCOLS• DEPEND ON THE TRANSPORT PROTOCOL USED
OSI MODEL AND TCP/IP • DEVELOPED BY INTERNATIONAL STANDARD ORGANIZATION• OSI MODEL• Is a theorical model• Modular• It is made up of 7 layers
• Each layer can communicate with its upper and lower layer• Each module is independent
• TCP/IP• It is the model used in networking• Modular• Four layers