Telecommunications company Windstream Holdings Inc. has agreed to sell its data center business to TierPoint LLC in an all-cash deal valued at $575 million. Windstream, which bought Iowa Telecommunications Services Inc. in 2009 and picked up a market that includes rural Iowa and Minnesota in the process, also agreed to a reciprocal agreement in which it will exchange products and services with TierPoint’s customers, enabling Windstream to continue to offer data center services. The boards of both companies have agreed to the transaction, which is expected to close in two to four months. Windstream has a data center in Newton. According to its website, TierPoint does not operate data centers in Iowa.