Hannibal's Alpine Route

Hannibal's Alpine route is fiercely debated but we know that the Alps had to be navigated across. There would have been a fair share of tribes who were happy to support Hannibal's campaign especially if they felt no loyalty to the Romans. The Rhone River was a considerable crossing and with the Voulke actively trying to prevent the crossing it raises the question what about the famous elephants. Did Hannibal have to find a way to transport the elephants over the river or were the elephants transported to the eastern side of the Rhone by sea? Livy says that some of the elephants fell into the Rhone and had to swim to safety.