Dubbed "stretched fabric" the technology is part of Cisco's Application Centric Policy Controller (APIC) which allows switches that form a fabric to be located up to 30 km apart.
The big idea is that the technology can provide better integration of environments spread across multiple data centres.
The stretched ACI fabric behaves the same way as a regular ACI fabric and supports full VMM integration. A VMWare vCenter can operate across the stretched ACI fabric sites with ESXi hosts from sites managed by the same vCenter and Distributed Virtual Switch.
Depending on optical transceivers between the data centres, the data can be stretched further. Cisco's said that the stretched fabric also requires dark fibre links.
All this simplifies the overall network infrastructure and removes the need for all leaf switches to be connected to all spines.