BROADCASTING IN THE ARROWHEAD TORUS

The ''arrowhead torus'' is a hierarchical Cayley graph that we define on the triangular (or ''hexavalent'') grid. A 3-port wormhole broadcas ting protocol is derived first from construction, then improved by usi ng edge-disjoint forests. A store-and-forward broadcasting protocol is derived afterwards, then improved by mixing pipelining and are-disjoi nt spanning trees. Costs are given in constant and linear time and com pared with lower bounds.