Often changes to IT systems or services requires changes to IP addresses or Domain Name System (DNS). These changes need to be reflected in the Domain Name Systems which caches information for 24 hours. This time frame is known as Time To Live (TTL) and an individual configuration option for each entry in the DNS system.
As part of the execution plan staff are encouraged to work with the DNS system administrators to change the TTL for the system being changed to 10 minutes at least two days before the change and back to 24 hours after the change has been successfully completed.