For now, I just want to drop off a link to a video that explains the basics of the Overlay Transport Virtualization (OTV) protocol. OTV is used in Ciscos Nexus 7000 to interconnect data center sites. Interconnecting distributed data center sites is still a major issue for instance when it comes to complex disaster recovery concepts. The protocol is currently a draft at IETF. I will post some more details on this topic in a future post.
Here a short summary provided by Cisco:
Overlay Transport Virtualization (OTV)
OTV is an industry-first solution that significantly simplifies extending Layer 2 applications across distributed data centers. You can now deploy Data Center Interconnect (DCI) between sites without changing or reconfiguring your existing network design. With OTV you can deploy virtual computing resources and clusters across geographically distributed data centers, delivering transparent workload mobility, business resiliency, and superior computing resource efficiencies. Key OTV features include:
- Extends Layer 2 LANs over any network: Uses IP-encapsulated MAC routing, works over any network that supports IP, designed to scale across multiple data centers
- Simplifies configuration and operation: Enables seamless deployment over existing network without redesign, requires minimal configuration commands (as few as four), provides single-touch site configuration for adding new data centers
- Increases resiliency: Preserves existing Layer 3 failure boundaries, provides automated multihoming, and includes built-in loop prevention
- Maximizes available bandwidth: Uses equal-cost multipathing and optimal multicast replication