Some information in the Caste system in India?

There are Four main classses.
Brahmins
Are priests and teachers-they are to spread their knowledge on
Kshtriyas
are warriors and rulers
Vaisyas
farmers merchants and etc...
Then there are sudras
Untouchables or undesirables
they are the lowest system, and have the undesirable jobs, hence their names.
In Hinduism, you are born into the same class every life, Believing in Reincarnation.
No one talk to sudras unless you are a sudra yourself. It is dishonorable to affiliate yourself with sudras. Varna is just a reference to the Main division of the classes.
Hope this helps