Sockets

Sockets are software abstraction of session layer in OSI model. It is used as a "terminal" between the connection of two machines.
It is a data structure which is an combination of Machine's IP Address and Ports [1024 - 49151]. These Ports will be pointed to the Machine's Memory Address Space. It paves the way for client-server communication.

netstat # used to view Sockets

Types of Sockets

There are 3 types of sockets, they are

1) SOCK_STREAM

Byte-by-Byte Stream Communication.

Connection Oriented Protocol

Sequenced, Reliable

Bi-directional Data Communication

eg. TCP,SCTP[Stream Controlled]

2) SOCK_DGRAM

Packet-by-Packet

Datagram Communication

Connectionless Protocol

No Ordering of data

Bi-directional Data Communication

eg. UDP

3) SOCK_RAW

Sending and Receiving Data,

bypassing all encapsulation

Packet Headers are not stripped off

eg. ICMP, IGMP, OSPF

Encapsulation of Packet