Round robin DNS is a technique in which load balancing is performed by a DNS server instead of a strictly dedicated machine. A DNS record has more than one value IP address.
When a request is made to the DNS server which serves this record, the answer it gives alternates for each request. For instance, if you had a three webserver that you wished to distribute requests between, you could setup your DNS zone as follows:
# vi /var/named/domain.com.db
Append/modfiy www entry:
www IN A 18.104.22.168
IN A 22.214.171.124 IN A 126.96.36.199
IN A 188.8.131.52 # /etc/init.d/named restart