This paper addresses the one-to-all broadcasting problem, and the one-to-many broadcasting problem, usually simply called broadcasting and multicasting, respectively. Inthispaper, we studythese problems underbothlinemodel, and cut-through model. The former assumes long distance calls between non neighboring processors. The latter completes the line model by taking into account the use of a routing function. It is known that one can find time optimal broadcast and multicast protocols in the line model in polynomial time. We present a new time optimal broadcasting and multicasting algorithminthe line model. This algorithm efficiently uses the bandwidth of the network. Moreover, it also applies to the cut-through model as soon as the routing function generates shortest paths only.