Hub and Spoke Dossier
One center, many rays: the layout that moves everything through the middle — and the trade it makes to get there.
The layout is exactly what the name says. One node is designated the center; every other node connects to the center and, in the pure form, to nothing else. Anything traveling between two spokes goes in to the middle and out again. The shape appears wherever many small flows must be served with few large vehicles.
In air transport the center is the hub airport. Flights arrive in coordinated banks, passengers and baggage transfer, and the bank departs; one airport can offer hundreds of city pairs while flying to only dozens of cities. In parcel logistics the center is the sorting hall, where every package is carried regardless of origin, so a truck from a small town can share an aircraft with freight from a capital.
In computer networks the center is the switch or concentrator of a star topology. Each device needs one cable, not a cable to every other device, and the center forwards each frame where it belongs. The same drawing serves a wheel: the rim is the ring of destinations, the spokes carry the load, and the hub passes it to the axle.
The case for the pattern is arithmetic. A full mesh among n points needs n(n − 1)/2 links; a star needs n − 1. Ten points mean 45 direct links against 9 through a center, and the gap widens with every added point. Fewer links mean fewer vehicles, simpler schedules, and one place to watch instead of many.
The case against it is the same arithmetic read from the other side. Neighbors detour through the middle; the center must be sized for the peak of everything at once; and the center's failure is everyone's failure. Working systems therefore compromise: a second hub, a fast spine between hubs, and direct routes between the busiest spokes — a star with a few extra lines drawn in.
Further reading