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Methods and systems are provided for efficient handover of a media session between heterogeneous Internet Protocol (IP) networks. A mobile device with Internet access can operate a software program to communicate with a corresponding node. The corresponding node may access the Internet through eithe

Methods and systems are provided for efficient handover of a media session between heterogeneous Internet Protocol (IP) networks. A mobile device with Internet access can operate a software program to communicate with a corresponding node. The corresponding node may access the Internet through either a Network Address Translation (NAT) router or a firewall. The mobile device establishes a media session with a corresponding node via the transmission of a first media stream and receipt of a second media stream, and a media control channel can optionally be implemented. The mobile device can acquire Internet access through a second IP address, and packets routed between the second IP address and the Internet may traverse a NAT router. The mobile device can evaluate the type of NAT at the second IP address from a stored Local Area Network (LAN) profile. A software routine can determine that handover of the media session from the first IP address to the second IP address is preferred. A software routine can determine efficient handover procedures according to Network handover rules. The mobile device may begin transmitting a third media stream to the corresponding node and the corresponding node can transmit a fourth media stream to the second IP address. A media control channel is optionally supported.

대표청구항 ▼

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 fi

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; anddetermining 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. 2. The system of claim 1, wherein, before the mobile device starts transmitting the first media stream, the corresponding node determines the second NAT router associated with the corresponding node comprises one of (i) the symmetric NAT router and (ii) the non-symmetric NAT router. 3. The method of claim 1, wherein the mobile device transmits a call-control signal to the corresponding node, wherein the call-control signal contains the third IP address and the second port. 4. The method of claim 1, wherein the non-symmetric NAT-router comprises one of a null, full cone, partial cone, and a port-restricted cone, NAT router, and wherein a null NAT router comprises using a public IP address, and wherein a port-restricted cone NAT router comprises an address-restricted cone NAT router. 5. The method of claim 1, wherein the IP address and port associated with the corresponding node is an IP address and port assigned to a second NAT router associated with the corresponding node, and wherein the second NAT router forwards packets received on the IP address and port associated with the corresponding node to the corresponding node. 6. The method of claim 5 further comprising identifying a fourth port on the external interface of the first network address translation (NAT) router, wherein the corresponding node sends a media-control packet to the fourth port. 7. The method of claim 1, wherein the media streams comprise packets containing media formatted according to a codec, and wherein the packets contain IP headers. 8. The method of claim 7, wherein the IP headers are compressed. 9. The method of claim 1, wherein the corresponding node receives the first and third media streams on the same IP address and port. 10. The method of claim 1, wherein the corresponding node transmits the fourth media stream and a media-control packet to the third IP address and the second port. 11. The method of claim 1, wherein the source IP address and the source port for packets in the fourth media stream as received at the mobile device is the IP address and port associated with the corresponding node. 12. The method of claim 1, wherein the corresponding node begins transmitting the fourth media stream before the corresponding node stops transmitting the second media stream. 13. The method of claim 1, wherein the mobile device begins transmitting the third media stream before the mobile device stops transmitting the first media stream. 14. The method of claim 1, wherein at least one of the mobile device and the corresponding node transmit a media-control packet to the other. 15. The method of claim 14, wherein the mobile device transmits and receives a media-control packet on one media-control port at the second IP address. 16. The method of claim 14, wherein at least one media-control packet is a non-media packet transmitted within the media streams. 17. The method of claim 1, wherein at least one of the first NAT router and the second NAT router covert a packet between an IP version 4 (Ipv4) address and an IP version 6 (Ipv6) address. 18. The method of claim 1, wherein the mobile device uses a local area network (LAN) profile to select the first handover procedure, wherein the mobile device records a second NAT-router type in the LAN profile before engaging in the media session, and wherein the mobile device identifies the second NAT-router type before acquiring the second IP address during the media session. 19. 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;using a local area network (LAN) profile to identify a network address translation (NAT)-router type of a NAT router associated with the second IP address, wherein the mobile device records the NAT-router type in the LAN profile before engaging in the media session, and wherein the mobile device identifies the NAT-router type before acquiring the second IP address during the media session;using a set of network handover rules to select a handover procedure based at least in part on the identified NAT-router type, wherein the set of network handover rules specifies various handover procedures corresponding with various NAT-router types including the identified NAT-router type; anddetermining that a handover of the media session from the first IP address to the second IP address is preferred, and responsively conducting the handover according to the selected handover procedure, wherein, as a result of conducting the handover, engaging in the media session comprises (a) transmitting a third media stream from the second IP address to the IP address associated with the corresponding node and (b) receiving a fourth media stream at the second IP address from the corresponding node. 20. The method of claim 18, wherein the identified NAT-router type is a NAT-router type selected from the group consisting of null, full cone, partial cone, port-restricted cone, and symmetric, wherein a null NAT-router type comprises using a public IP address, and wherein a port-restricted cone comprises an address-restricted cone. 21. The method of claim 18, wherein the media session is managed by a communications service, and wherein a user gains access to the communications service by accepting a user agreement. 22. The method of claim 18, wherein a media control channel provides feedback to the mobile device on the quality of media received by the corresponding node, and wherein the mobile device uses the same port number at the second IP address to send and receive data for the media control channel. 23. The method of claim 18, further comprising identifying a third IP address and a third port on an external interface of the NAT router associated with the second IP address, and wherein packets received at the third IP address and the third port are routed to the second IP address and the second port. 24. The method of claim 23, further comprising the mobile device transmitting a call-control signal to the corresponding node, wherein the call-control signal contains the third IP address and the third port, and wherein the corresponding node begins transmitting the fourth media stream after receiving the call-control signal. 25. The method of claim 24, wherein the call-control signal comprises at least one packet inserted within at least one of the first media stream and a media control channel. 26. The method of claim 24, wherein the mobile device begins transmitting the third media stream before transmitting the call control signal. 27. The method of claim 18, wherein the corresponding node transmits the fourth media stream to a source IP address and a source port for a packet received in the third media stream. 28. The method of claim 18, wherein the corresponding node routes packets through a second NAT router, and wherein the corresponding node receives the first media stream and the third media stream on the same IP address and the same port, and wherein packets transmitted to the IP address and port associated with the corresponding node route to the external interface of the second NAT router. 29. The method of claim 18, wherein the mobile device transmits the first media stream and receives the second media stream on the same IP address and the same port. 30. The method of claim 18, wherein the corresponding node begins transmitting the fourth media stream before the corresponding node stops transmitting the second media stream. 31. The method of claim 18, wherein the mobile device begins transmitting the third media stream before the mobile device stops transmitting the first media stream. 32. The method of claim 18, wherein the source IP address and the source port for packets received in the fourth media stream by the mobile device is the IP address and the port associated with the corresponding node. 33. The method of claim 18, wherein the mobile device monitors both (i) the first IP address and the first port for receiving the second media stream and (ii) the second IP address for receiving the fourth media stream. 34. The method of claim 18, wherein the mobile device determining that the handover of the media session from the first IP address to the second IP address is preferred comprises the mobile device measuring and comparing a quality of the network at the first IP address and a quality of the network at the second IP address. 35. The method of claim 18, wherein the NAT router coverts a packet between an IP version 4 (Ipv4) address and an IP version 6 (Ipv6) address. 36. A method for handover of an active media session, the method comprising in combination: transmitting a first media stream from a mobile device from a first Internet Protocol (IP) address to an IP address associated with a corresponding node, wherein the mobile device receives a second media stream from the corresponding node;acquiring a second IP address associated with the mobile device;determining both (i) a first network address translation (NAT)-router type of a NAT router associated with the corresponding node and (ii) a second NAT-router type of a NAT router associated with an alternate network;using a set of network handover rules to select a handover procedure based at least in part on both the first and second determined NAT-router types, wherein the set of network handover rules specifies various handover procedures corresponding with various sets of one or more NAT-router types including the at least one determined NAT-router type; anddetermining that a handover of the media session from the first IP address to the second IP address is preferred, and responsively conducting the handover according to the selected handover procedure, wherein conducting the handover comprises (a) transmitting a call-control signal from the mobile device to the corresponding node, wherein the mobile device begins receiving a fourth media stream transmitted by the corresponding node after transmitting the call-control signal and (b) transmitting a third media stream from the mobile device via the second IP address to a source port in the fourth media stream. 37. The method of claim 36, wherein at least one determined NAT-router type is a NAT-router type selected from the group consisting of null, full cone, partial cone, port-restricted cone, and symmetric, and wherein a null NAT-router type comprises using a public IP address, and wherein a port-restricted cone comprises an address-restricted cone. 38. The method of claim 36, further comprising using a local area network (LAN) profile to identify the second NAT-router type wherein the mobile device records the NAT-router type in the LAN profile before engaging in the media session. 39. The method of claim 36, wherein the mobile device transmits both the first and third media streams to the IP address and a port associated with the corresponding node. 40. The method of claim 36, further comprising identifying a third IP address and an external port on an external interface of the NAT router associated with the alternate network, wherein packets received at the third IP address and external port are routed to the second IP address. 41. The method of claim 40, wherein the call-control signal contains the third IP address and the external port. 42. The method of claim 36, wherein the mobile device uses one port to transmits the third media stream and receive the fourth media stream. 43. The method of claim 36, wherein at least one of the first NAT router and the second NAT router coverts a packet between an IP version 4 (Ipv4) address and an IP version 6 (Ipv6) address. 44. The method of claim 36, wherein determining that the handover of the media session from the first IP address to the second IP address is preferred comprises the mobile device measuring and comparing a quality of the network at the first IP address and a quality of the network at the second IP address. 45. The method of claim 36, wherein the corresponding node identifies a source IP address and a source port for packets in the third media stream as received at the corresponding node, and wherein the corresponding node transmits the fourth media stream to the identified source IP address and source port. 46. The method of claim 36, wherein the mobile device receives the fourth media stream at the second IP address and a port utilized to transmit the third media stream. 47. The method of claim 36, wherein the corresponding node begins transmitting the fourth media stream before the corresponding node stops transmitting the second media stream. 48. The method of claim 36, wherein the mobile device begins transmitting the third media stream before the mobile device stops transmitting the first media stream. 49. The system of claim 36, wherein the mobile device monitors both (i) the first IP address for receiving the second media stream and (ii) the second IP address and the associated port for receiving the fourth media stream. 50. The method of claim 36, wherein at least one of the mobile device and the corresponding node transmit a first media control packet using a media control port, wherein a second media control packet is received on the media control port. 51. The system of claim 50, wherein the media control packet is a non-media packet within a media stream. 52. The method of claim 36, wherein the corresponding node is a relay for communication with a terminating node. 53. The method of claim 36, wherein each of the media streams comprises a separate series of packets, wherein each such series of packets contains a separate set of digitized media, wherein each such set of digitized media comprises at least one of voice and video, and wherein each such series of packets is routed through a public Internet and contains a header including a packet source IP address, a packet source port number, a packet destination IP address, and a packet destination port number. 54. A method for handover of an active media session, the method comprising: transmitting a first media stream from a mobile device via a first Internet Protocol (IP) address and a first port to an IP address and a port associated with a corresponding node, wherein the mobile device receives a second media stream from the corresponding node;acquiring a second IP address associated with the mobile device, wherein the mobile device transmits a third media stream from the second IP address and a second port to the IP address and the port associated with the corresponding node, and wherein the third media stream starts before the first media stream ends;transmitting the third media stream from the mobile device via the second IP address and a second port to the IP address and the port associated with the corresponding node;identifying a third IP address and a third port on an external interface of a first network address translation (NAT) router after the first media stream starts, wherein packets received at the third IP address and the third port are routed to the second IP address and the second port;transmitting a call-control signal from the mobile device to the corresponding node before the first media stream ends, wherein the call-control signal includes the third IP address and the third port; andreceiving a fourth media stream at the mobile device on the second IP address and the second port, wherein the fourth media stream is transmitted by the corresponding node with a destination IP address and a destination port of the third IP address and the third port. 55. The method of claim 54, wherein the first NAT router is not a symmetric router, and wherein the IP address and the port associated with the corresponding node comprise an external interface on a non-symmetric NAT router. 56. The method of claim 54, wherein the IP address associated with the corresponding node is a publicly routable IP address on an external interface of a second NAT router, and wherein an IP address assigned to the corresponding node is a private IP address, wherein the second NAT router forwards packets from the IP address associated with the corresponding node to the IP address assigned to the corresponding node, and wherein the second NAT router is of a NAT-router type selected from the group consisting of null, full cone, partial cone, port-restricted cone, and symmetric. 57. The method of claim 54, wherein a software program operates on the mobile device for conducting the media session, wherein a communications service manages the software program, and wherein a user gains access to the communications service by accepting a user agreement. 58. The method of claim 54, further comprising the mobile device accessing a LAN profile for identifying a NAT-router type associated with the first NAT router, and wherein the first NAT router is of a NAT-router type selected from the group consisting of null, full cone, partial cone, port-restricted cone, and symmetric. 59. The method of claim 58, further comprising the mobile device using a set of network handover rules to select a handover procedure based at least in part on the identified NAT-router type associated with the first NAT router, wherein the set of network handover rules specifies various handover procedures corresponding with various sets of one or more NAT-router types including the identified NAT-router type, the method further comprising the mobile device using the selected handover procedure to conduct a handover from the first IP address to the second IP address. 60. The method of claim 54, wherein the mobile device measures and compares a quality of the network at the first IP address and a quality of the network at the second IP address, and responsively determines that a handover of the media session to the second IP address is preferred. 61. The method of claim 54, wherein the mobile device projects at least one of a quality of the network at the first IP address and a quality of the network at the second IP address, and responsively determines that a handover of the media session to the second IP address is preferred. 62. The method of claim 54, wherein the corresponding node begins transmitting the fourth media stream before the corresponding node stops transmitting the second media stream. 63. The method of claim 54, wherein the mobile device begins transmitting the third media stream before the mobile device stops transmitting the first media stream. 64. The method of claim 54, wherein at least one of the mobile device and the corresponding node transmit a first media control packet using a media control port, wherein a second media control packet is received at the media control port. 65. The method of claim 54, wherein the call-control signal comprises at least one packet inserted within at least one of the first media stream and a media control channel. 66. The method of claim 54, wherein the mobile device comprises at least one of a mobile phone handset, a laptop computer, a personal digital assistant (PDA) and a device that communicates with radio-frequency spectrum, and wherein the mobile device includes at least one of a session initiation protocol user agent, an extensible messaging and presence protocol user agent, a peer-to-peer client, a VoIP client, an IP Multimedia Subsystem client and a program that is downloaded and installed on the mobile device. 67. The method of claim 54, wherein each of the first and second media streams comprises a series of packets containing media formatted according to a codec, and wherein the series of packets contain IP headers. 68. The method of claim 66, wherein the IP headers are compressed, and wherein User Datagram Protocol (UDP) checksums on the series of media packets are disabled. 69. The method of claim 54, wherein the corresponding node uses the same port to (i) receive the first and third media streams and (ii) transmit the fourth media stream. 70. The method of claim 54, wherein first NAT router coverts a packet between an IP version 4 (Ipv4) address and an IP version 6 (Ipv6) address. 71. The method of claim 54, wherein the corresponding node is a relay for communication with a terminating node. 72. The method of claim 54, wherein the corresponding node starts transmitting the fourth media stream before the corresponding node starts receiving the third media stream. 73. A method for handover of an active media session, the method comprising in combination: transmitting a first media stream from a mobile device via a first Internet Protocol (IP) address and a first port to an IP address and port associated with a corresponding node, wherein the mobile device receives a second media stream from the corresponding node;acquiring a second IP address associated with the mobile device, wherein the mobile device transmits a third media stream from the second IP address and a second port to the IP address and the port associated with the corresponding node;identifying a third IP address and a third port on an external interface of a first network address translation (NAT) router after the first media stream starts, wherein packets received at the third IP address and the third port are routed to the second IP address and a second port;transmitting a call-control signal from the mobile device to the corresponding node before the first media stream ends, wherein the call-control signal contains the third IP address and the third port;receiving a fourth media stream at the mobile device on the second IP address and the second port before the third media stream starts;identifying a fourth IP address and a fourth port, wherein the fourth IP address and the fourth port are the source IP address and the source port for media packets in the fourth media stream as received at the mobile device; andtransmitting the third media stream from the mobile device via the second IP address and the second port to the fourth IP address and the fourth port. 74. The method of claim 73, wherein the IP address associated with the corresponding node is a publicly routable IP address on an external interface of a second NAT router, wherein an IP address assigned to the corresponding node is a private IP address, wherein the second NAT router forwards packets from the IP address associated with the corresponding node to the IP address assigned to the corresponding node, and wherein the second NAT router is of a symmetric NAT-router type. 75. The method of claim 73, wherein at least one of the first NAT router and the second NAT router coverts a packet between an IP version 4 (Ipv4) address and an IP version 6 (Ipv6) address. 76. The method of claim 73, further comprising the mobile device using a set of network handover rules to select a handover procedure based at least in part on the identified NAT-router type associated with the first NAT router, wherein the set of network handover rules specifies various handover procedures corresponding with various sets of one or more NAT-router types including the identified NAT-router type, the method further comprising the mobile device using the selected handover procedure to conduct a handover from the first IP address to the second IP address. 77. The method of claim 73, wherein the mobile device measures and compares a quality of the network at the first IP address and a quality of the network at the second IP address, and responsively determines that a handover of the media session to the second IP address is preferred. 78. The method of claim 73, wherein the mobile device projects at least one of a quality of the network at the first IP address and a quality of the network at the second IP address, and responsively determines that a handover of the media session to the second IP address is preferred. 79. The method of claim 73, wherein the corresponding node begins transmitting the fourth media stream before the corresponding node stops transmitting the second media stream. 80. The method of claim 73, further comprising the mobile device accessing a LAN profile for identifying a NAT-router type associated with the first NAT router, wherein the mobile device determines the NAT-router type before the first media stream starts, and wherein the NAT-router type is not symmetric. 81. The method of claim 73, wherein at least one of the mobile device and the corresponding node transmits a first media control packet using a media control port, wherein a second media control packet is received at the media control port. 82. The method of claim 73, wherein the call-control signal comprises at least one packet inserted within the set containing the first media stream and a media control channel. 83. The method of claim 73, wherein the mobile device monitors both (i) the first IP address and the first port for receiving the second media stream and (ii) the second IP address and the second port for receiving the fourth media stream. 84. The method of claim 73, wherein each of the first and second media streams comprise a series of packets containing media formatted according to a codec, and wherein the series of packets contain IP headers. 85. The method of claim 84, wherein the IP headers are compressed, and wherein User Datagram Protocol (UDP) checksums on the series of media packets are disabled. 86. The method of claim 73, wherein the corresponding node receives the first and third media streams on the same IP address and port. 87. The method of claim 73, wherein the first NAT router routes packets in the fourth media stream from the third IP address and the third port to the second IP address and the second port.