What are the functions of TCP and IP?

TCP/IP is a protocol suite that defines the exchange of transmissions across Internet. It is a 5 layer protocol suite. TCP is the transport layer protocol. It is connection-oriented, reliable transport protocol. TCP allows the sending process to deliver data as a stream of bytes and allows the receiving process to obtain data as a stream of bytes. TCP creates an environment in which the two process seem to be connected by an imaginary tube that carries their data across the Internet. TCP offers full duplex service in which data can flow in both directions at the same time. TCP is a reliable transport protocol. It uses an acknowledgement mechanism to check the safe and sound arrival of data. TCP use flow control. The receiver of the data controls the amount of data that are to be sent by the sender. TCP also provide error control and congestion control.

Internet working Protocol (IP) is the transmission mechanism used by the TCP/IP protocols. It is an unreliable and connection less protocol used by the internet layer in the 5 layer TCP/IP protocol suite. IP transports data in packets called datagrams each of which is transported separately. Datagrams can travel along different routes and can arrived out of sequence or be duplicated. IP does not keep track of the routes and has no facility for reordering datagrams once they arrive at their destination. IP uses four supporting protocols.

ARP: Address Resolution Protocol
RAPP: Reverse Address Resolution Protocol
ICMP: Internet Control Message Protocol
IGMP: Internet Group Message Protocol

ARP is used to associate a logical address with a physical address.

RAPP allows a host to deliver its Internet address when it knows only its physical address.

ICMP is a mechanism used by hosts and gateways to send notification of datagram problems back to sender.

IGMP is used to facilitate the simultaneous transmission of a message to a group of recipients.