Global VOD content distribution

Design the CDN / content-distribution strategy for a global VOD service pushing tens of Tbps at peak, where 90% of bytes are a small catalog of popular titles but the long tail still matters. You want to serve most bytes from inside or adjacent to ISP networks to cut transit cost and improve QoE. Design the cache hierarchy, content placement/fill strategy, and how you decide what lives where, including handling a brand-new release that everyone wants at once.