For understanding the networking we have to need know many of things which helps us on further.

Note  :- I am writing this in simple manner to easily understand.

Protocol:-

• Protocol are responsible for end to end communication.
• It is a set of rules or instruction because it defines rule & regulation of communication.
• Protocol is small piece of software.
• Protocol are divided in 5 categories.
  • These highlight the function
  • Communication Protocol

1.  
   1.  
      1. TCP/IP
      2. UDP/IP
      3. SPX /IPX
2.  

• Routing Protocol

1.  
   1.  
      1. IGP
2.  
   1.  
      1.  

• RIP
• IGRP
• EIGRP
• OSF
• IS-IS

1.  
   1.  
      1. EGP
2.  
   1.  
      1.  

• BGP
• Routed Protocol
• IP
• IPX
• Transport Protocol

1.  
   1.  
      1.  
         1.  
            1. TCP
            2. VDP
            3. SPX
2.  

• Application Protocol

1.  
   1.  
      1. HTTP
      2. FTTP
      3. TFTP
      4. DHCP
      5. SMTP
      6. POP
      7. DNS

•  

Services :- Telnet ,SSH

Explain:-

• Communication Protocol:- it is mixture of two categories , Routed & Transport. ,it is also further divided into two part : routable and Non Routable .In Routable it consist LAN +WAN ,TCP/IP,VDP/IP and IN Non Routable consist LAN &SPX/PX.
• Routing Protocol :- These are basically use to perform the communication between two different network.Function of routing protocol are basically to define the both to reach the destination.
• Routed Protocol :- Source and Destination.
• Transport Protocol :- Carrying the packet & information.
• Application Protocol :- These are the protocol use to increase the reliability ,performance and security of network.

1.  
   1.  
      1. DHCP
      2. Telnet ,SSH (remote access)
      3. DNS

Use the concept of port number.

What is Port?

Port is a 16bit logic number. Limit of port number is 2^n =2^16=65536.

Port are divided into two parts:-

1. Well known Ports

Starts – 0 to 1014

1. Unknown Ports

Starts – 1015 to 65536

Some Important No. Of Port are :-

ICMP                  1

TCP                     6

UDP                    17

FTP                     20/21

SSH                     22

Telnet                23

SMTP                 25

RDP                    27

Time                   37

DNS                    53

DHCP                 67/68

TFTP                   69

HTTP                  80

POP                    110

For More number please click here