Bisection bandwidth
Beginner
Cut a team of chips in half. This is how much data per second can cross between the two halves.
Novice
The total bandwidth of the links crossing the worst-case cut that splits the chips into two equal halves. It limits traffic where every chip talks to chips far away, such as all-to-all.
Expert
Minimum over balanced cuts of the cut capacity. Full-bisection switched fabrics give ; a ring gives a constant (2 links); a 2D torus gives links per direction, twice a mesh without wraparound.
Explained in Scale-up fabrics (Systems).