If a graph contains only undirected edges, then the graph is an undirected graph. In other words, the edges in an undirected graph are bidirectional. Sometimes, the undirected graph is also known as an undirected network. In an undirected graph, if vertex A is connected to vertex B, then it is assumed that both (A, B) and (B, A) represent the same edge. The following diagram shows an example of an undirected graph where all the edges do not have arrows to indicate direction: