What is a DCI?

As you get more and more into Cisco Data Center terminology you come across the term DCI. ┬áDCI is a Data Center Interconnect. DCI’s typically come in 3 categories.

Dark Fiber (CWDM/DWDM)
MPLS Layer 2 VPN (VPWS/VPLS)
MPLS Layer 3 VPN

A DCI is basically a LAN extension over one of the above methods.