Patent ID: 8165091
Filing Date: 2012-04-24
Classification: H04L,H04W

Abstract:
1. A method for a mobile device to conduct a handover of an active media session, the method comprising the mobile device: engaging in a media session, wherein engaging in the media session initially comprises (a) transmitting a first media stream from a first Internet Protocol (IP) address and a first port to an IP address and port associated with a corresponding node and (b) receiving a second media stream at the first IP address from the corresponding node; acquiring a second IP address; identifying a third IP address and a second port on an external interface of a first network address translation (NAT) router, wherein packets received at the third IP address and the third port are routed to the second IP address and a third port; determining a first NAT-router type for a second NAT router associated with the corresponding node comprises one of non-symmetric NAT router and a symmetric NAT router; selecting one of a (i) first handover procedure wherein the first NAT-router type comprises a non-symmetric NAT router and (ii) a second handover procedure wherein the first NAT-router type comprises a symmetric NAT router, wherein the first handover procedure specifies a third media stream sent from the second IP address includes a destination port number the same as a source port number in the second media stream, and wherein the second handover procedure specifies (a) the corresponding node sends a fourth media before the mobile device sends the third media stream and (b) the fourth media stream includes a destination port the same as the second port; and determining that a handover of the media session from the first IP address to the second IP address is preferred, wherein, after the handover, engaging in the media session comprises (a) transmitting a third media stream from the second IP address and the second port to the IP address associated with the corresponding node and (b) receiving a fourth media stream at the second IP address and the third port from the corresponding node.