- East-west traffic
- Data flowing between servers or accelerators inside a data center, as opposed to north-south traffic between the building and external users. AI training is dominated by east-west traffic as accelerators synchronize state in lockstep, making the intra-cluster fabric a hard capacity constraint.
- Fabric (intra-cluster)
- The network of switches, optical transceivers, and cabling that wires the accelerators of a training cluster to one another. Its capacity requirement scales superlinearly with cluster size, so it strains its supply chain harder and faster than the compute layer as clusters grow.
- Hyperscaler cable ownership
- The practice of the largest cloud and content companies funding subsea and long-haul cables outright, or dominating consortia, because their internal traffic alone justifies the investment. It vertically integrates the interconnect leg and turns a cable announcement into a sharp signal of intended compute geography.
- Interconnect
- The physical and logical fabric that moves data into, out of, and within compute clusters, spanning three nested scales: subsea and long-haul fiber, metro fiber and data center interconnect, and the intra-cluster switch-and-optics fabric. The course treats it as a distinct third leg of the AI infrastructure capital stack alongside compute and power.
- Optical transceiver
- A module at each end of an optical link that converts electrical signals to modulated light and back. Large clusters require enormous quantities, its manufacture depends on specialized photonics and precision assembly that cannot scale overnight, and the course identifies its leading edge as a durable choke point.
- Route diversity
- The number of physically independent paths connecting two points. Diversity provides resilience against a single cut, and because its value appears only on the day of a failure, the course argues markets systematically underprice it, making it a recurring source of mispriced interconnect assets.
- Subsea cable consortium
- A group of owners jointly funding a transoceanic cable and sharing its capacity. Historically composed of telecom carriers spreading cost and risk, the consortium model is being displaced as hyperscalers fund cables for their own internal traffic, changing where pricing power sits.
- Switch silicon
- The chip at the heart of a network switch, whose total throughput determines how many accelerators can be connected with how many tiers of switching. A generational jump in switch-silicon capacity relieves pressure across the whole optics supply chain by reducing the number of switches and transceivers a cluster needs.