A network decomposition is a nice partition of your graph makes many local distributed problems tractable (e.g., coloring).

Strong network decomposition: You partition your graph into parts, such that the induced subgraph on each part consists of a collection of low-diameter graphs

It’s usually ok to have a weak network decomposition instead. It’s the same thing, except instead of having connected components of diameter , you have clusters where the distance between each pair of points in a cluster (allowing you to use edges in ) is at most , and the clusters can’t have any edges between them (but ofc there might be a path that leaves the part and then comes back into a new part).