PROTOCOLS

LAYER 4 OR TRANSPORT LAYER

ALL TYPES OF PROTOCOL ARE AVAILABLE IN THIS LAYER. IT IS ALSO CALLED AS “ HEART OF OSI ”.

PORT NUMBER : - IT IS THE ENTRY OF PROTOCOL IN THE O/S. THERE ARE TOTAL 65,555 PORTS AVAILABLE. IN THIS 0 – 1023 PORTS ARE RESERVED.

EX : - HTTP – 80

FTP – 21

SMTP – 25.

NNTP – 119.

POP3 – 109.

IMAP4 – 143.

TELNET – 23.

DNS – 53.

DHCP – 67.

TFTP – 69.






PROTOCOLS

PROTOCOL : IT IS A SET OF RULES AND REGULATIONS TO TRANSFER INFORMATION
FROM TWO COMPUTERS IN THE SAME NETWORK.
TOTAL 0 – 65,535 PORTS ARE AVAILABLE , WHICH ALLOW TO COMMUNICATE TWO COMPUTERS BY USING DIFFERENT PROTOCOLS.

0 – 1023 PORTS ARE RESERVED PORTS.



TYPES OF PROTOCOLS


1. CONNECTION ORIENTED : EX : - TCP.

2. CONNECTION LESS : EX : - UDP.