Directed graphs(digraphs) A directed graph(digraph)G=(N,A is a finite nonempty set of nodes N and a set of ordered node pairs a called directed arcs. N={1,2,34} A={(1,2),(2,1),(1,4) (4,2),(4,3),(3,2)} Directed walk:(4, 2, 1, 4, 3, 2) Directed path:(4, 2, 1) Directed cycle: (4, 2, 1, 4) Data networks are best represented with digraphs, although ty pically links tend to be bi-directional (cost may differ in each direction) For simplicity we will use bi-directional links of equal costs in our examplesDirected graphs (digraphs) • A directed graph (digraph) G = (N,A) is a finite nonempty set of nodes N and a set of ordered node pairs A called directed arcs. 1 2 3 4 N = {1,2,3,4} A = {(1,2), (2,1),(1,4), (4,2), (4,3),(3,2)} • Directed walk: (4,2,1,4,3,2) • Directed path: (4,2,1) • Directed cycle: (4,2,1,4) • Data networks are best represented with digraphs, although typically links tend to be bi-directional (cost may differ in each direction) – For simplicity we will u se bi-directional links of equ al costs in our examples Eytan Modiano Slide 5