TCP/IP and Protocol Suite
The transmission control protocol/ Internet protocol (TCP/IP) was built up by the Defense Advanced Research Project Agency (DARPA) in the early year of 1970s to interconnect computers in the Advanced Research Projects Agency Network (ARPANET). The TCP/IP consists of various major protocols, such like Internet protocol; Telnet, transmission control protocol, file transfer protocol (FTP), and simple mail transfer protocol (SMTP). This is compatible with work ing on a broad range of computing systems, such like minicomputers, mainframes and microcomputers. It might be utilized to transfer files between heterogeneous systems such as, DEC, SUN, Macintosh, IBM, and many other computers. This is supported by all UNIX vendors and included in software packages by the SUN Microsystems Unix operating system. Depend on TCP/IP, a number of application protocols have been developed, which includes FTP, Telnet network file system (NFS), simple mail transfer protocol (SMTP), and simplified network management protocol (SNMP).
To establish communication among two hosts, first, a socket (end point of communication) is created by a system call with a specification of destination. It utilizes an associated data structure that stores all the essential information for the communication and a data buffer. Each data is broken into small pieces & sent to the socket with an assigned protocol. The IP, TCP and Ethernet headers are added to the packet before it obtains transferred to the Ethernet cable.
The TCP header comprises source port, sequence number, destination port, acknowledgement number, urgent pointer, checksum, and additional flags. The IP header includes kinds of service total message length, fragment flags, ID, protocol, header checksum, source and destination address, and so forth. The header information is stripped off the data packet from the destination host and suitable action is being taken to make sure the correct data transfer. When utilizing an application such as FTP or TELNET, the user only require specify the destination host name.