Round robin DNS is used for balancing the load of distributed Web servers in very basic way. It is done by setting up multiple resource records of the same type or having a domain name with multiple websites on different servers with different IP addresses. When a user comes to the website they will be sent to the next IP address that is in order. The next user will go to the next IP address and so on. As an IP address is given out it goes to the end of the IP address list. Round robin DNS does not take into account which servers are being hit with the heaviest traffic, it just mindlessly goes from one IP address to the next.
See also:
Load Balancing
IP Address
Resource Record
Domain Name