It's common business policy for organizations of a certain size to have two data centers as part of a disaster recovery or business continuity plan. However, most enterprise - applications are not designed for or intended to use systems in two different locations.
Enter the notion of a data center interconnect, which extends an Ethernet network between two physically separate data centers. While the idea is simple, Ethernet wasn't designed to run across a wide area network. Thus, a DCI implementation requires a variety of technological fixes to work around Ethernet's limitations.
This report outlines the issues that complicate DCIs, such as loops that can bring down networks and traffic trombones that eat up bandwidth. It also examines the variety of options companies have to connect two or more data centers, including dark fiber, MPLS services and MLAG, as well as vendor specific options such as Cisco OTV and HP EVI. The report looks at the pros and cons of each option.