Packet Data Transmission
A method and system, for transmitting data to a mobile node ( 4 ) over a unidirectional link ( 12 ) in a packet data network, for example an IP network, comprises: sending a message from a protocol address, e.g. IP address, of a bidirectional interface at the mobile node ( 4 ) to the home agent ( 6 ), the message comprising a protocol address of a unidirectional interface at the mobile node ( 4 ), wherein the protocol address of the bidirectional interface is different to the protocol address of the unidirectional interface; the home agent ( 6 ) transmitting data to the mobile node ( 4 ) using the protocol address of the unidirectional interface as the care-of-address; and delivering the transmitted data via the unidirectional link ( 12 ) to the unidirectional interface of the mobile node ( 4 ). The protocol address of the unidirectional interface may be contained in the message in the form of an extension appended to a registration.
1 . A method for transmitting data to a mobile node over a unidirectional link in a packet data network, the method comprising:
sending a message from a protocol address of a bidirectional interface at the mobile node to a home agent of the mobile node, the message comprising a protocol address of a unidirectional interface at the mobile node coupled to the unidirectional link, wherein the protocol address of the bidirectional interface is different to the protocol address of the unidirectional interface;
the home agent transmitting data to the mobile node using the protocol address of the unidirectional interface as the care-of-address; and
delivering the transmitted data via the unidirectional link to the unidirectional interface of the mobile node.
2 . A method of operating a mobile node in a packet data network, the method comprising sending a message from a protocol address of a bidirectional interface at the mobile node to a home agent of the mobile node, the message comprising a protocol address of a unidirectional interface at the mobile node coupled to the unidirectional link, wherein the protocol address of the bidirectional interface is different to the protocol address of the unidirectional interface.
3 . A method according to claim 1 , wherein the message comprises the protocol address of the unidirectional interface in the form of an extension appended to a registration request compliant with the protocol.
4 . A method according to claim 1 , wherein the packet data network is a Mobile IP network and the protocol addresses are IP addresses.
5 . (canceled)
6 . A system for transmitting data over a unidirectional link in a packet data network, comprising:
a mobile node and a home agent;
the mobile node being arranged to send a message from a protocol address of a bidirectional interface at the mobile node to the home agent, the message comprising a protocol address of a unidirectional interface at the mobile node coupled to the unidirectional link, wherein the protocol address of the bidirectional interface is different to the protocol address of the unidirectional interface; and
the home agent being arranged to transmit data to the mobile node using the protocol address of the unidirectional interface as the care-of-address.
7 . A system according to claim 6 , wherein the message comprises the protocol address of the unidirectional interface in the form of an extension appended to a registration request compliant with the protocol.
8 . A system according to claim 6 , wherein the packet data network is a Mobile IP network and the protocol addresses are IP addresses.
9 . A mobile node for a packet data network;
wherein the mobile node is arranged to send a message from a protocol address of a bidirectional interface at the mobile node to a home agent, the message comprising a protocol address of a unidirectional interface at the mobile node coupled to the unidirectional link, wherein the protocol address of the bidirectional interface is different to the protocol address of the unidirectional interface.
10 . A mobile node according to claim 9 , wherein the message comprises the protocol address of the unidirectional interface in the form of an extension appended to a registration request compliant with the protocol.
11 . A mobile node according to claim 9 , wherein the packet data network is a Mobile IP network and the protocol addresses are IP addresses.