1. A method for supporting handover of a media session using a media handover relay, the method comprising the media handover relay: receiving a message that includes a destination IP address and a destination port number; receiving a first media stream; sending a second media stream to the destination IP address and the destination port number, which second media stream includes at least a portion of the first media stream; receiving a third media stream from the destination IP address, wherein the media handover relay starts receiving the third media stream after the media handover relay starts sending the second media stream; and, receiving an authentication message, and, after receiving such authentication message, sending at least one packet in the second media stream.