TCP is connection oriented communication. It uses a three way
handshake to establish a connection before coms begins it acknowledges
when packets are recieved. It uses ICMP to establish transfer rate.
ICMP is the way errors are reported. Routes are challeged and
established based on network trafic using ICMP.
IP is a conectionless comunication a fire and forget form of
comunication
Why use IP?... less traffic.
TCP/IP works on five network layers 1 application 2 TCP 3 IP 4 network
interface 5 physical. Check out OSI layers as well for a better
understanding.
An IP adress is much like a house adress or phone number it locates a
computer on the net. It can have subnetting to allow more or less
hosts and networks.
SMTP is Simple Mail Transport Protocol it uses TCP and is made up of a
mailbox & a computer.
Hope that helps????