Method and apparatus for providing IP mobility for mobile networks

In a communication system comprising a mobile router attached to a mobile network, a method comprising:

• communicating information, via a multicast routing tree, between the mobile network and a selected external network;
• determining, while the mobile network is joined to the selected external network via the multicast routing tree, that an alternative external network is preferred;
• selecting the alternative external network for communication with the mobile network;
• and
• issuing commands to a packet network causing the packet network to establish a new branch of the multicast routing tree leading to the alternative external network.

In a communication system comprising a mobile router operably connected to a mobile network node, a method comprising the mobile router performing steps of:

• intercepting one or more IP packets sent from the mobile network node to a correspondent node, the one or more IP packets including a source address field defining a source IP address of the mobile network node;
• replacing, in the source address field, the source IP address of the mobile network node with a care of source address associated with an external network interface;
• adding, to the one or more IP packets, a home address extension field including the source IP address of the mobile network node;
• and
• sending the one or more IP packets to the correspondent node, via the external network interface.

A mobile router comprising:

• a mobile network interface operably connecting the mobile router to one or more mobile network hosts defining a mobile network;
• a multicast care of address binding management element for associating, a multicast care of address with the mobile network, wherein the multicast care of address is adapted for use as a proxy address for the one or more mobile network hosts;
• and
• a receiver for receiving packets destined to at least one of the one or more mobile network hosts via the multicast care of address as the mobile network moves throughout the communication system.