Hierarchical SDN for Hyper-Scale, Hyper-Elastic Data Center and Clouds
Hierarchical SDN (HSDN) is an architectural solution that can scale to support tens of millions of network endpoints (e.g., servers) using very small forwarding tables in the network nodes. The two distinguishing characteristics of the HSDN forwarding plane are: i) all paths in the network are pre-established in the forwarding tables, and ii) the labels identify entire paths rather than simply destinations. These properties, which at scale are unique to the HSDN architecture, enable to operate the network in a fundamentally new way, optimally handling both ECMP and any-to-any end-to-end TE, and achieving high network utilization with small buffers in the switches. Other key benefits of HSDN are very low cost, high availability and scalability, and superior elasticity.