Methods and apparatus for providing mobility of a node that does not support mobility

DETAILED DESCRIPTION The present invention provides methods and apparatus for enabling a node that does not support Mobile IP to roam to various Foreign Agents so that it may receive packets sent to it by a corresponding node.
This is accomplished, in part, through enabling a Foreign Agent to independently perform registration on behalf of the node.
In addition, a Home Agent associated with the node independently performs de-registration on behalf of the node when the node roams to a Foreign Agent from the Home Agent or another Foreign Agent.
It is important to note that this is achieved without any communication from the node indicating its desire to register or de-register.
Moreover, because the node does not implement the Mobile IP protocol, it is desirable to implement a virtual Foreign Agent such that the node appears to send a packet to only one Foreign Agent rather than to different Foreign Agents each time the node roams to a new Foreign Agent.
Since the node does not support Mobile IP, it is preferable that it appears to the node that the node is sending and receiving packets through only one router (e.
g.
, Foreign Agent) that is the default gateway.
According to one aspect of the invention, this is accomplished through the implementation of a virtual Foreign Agent.
Thus, in a Foreign Agent supporting Mobile IP, a method of implementing a virtual Foreign Agent in a network having a plurality of Foreign Agents includes associating a single dummy interface IP address with an interface of each one of the plurality of Foreign Agents.
In this manner, a dummy interface IP address is associated with each Foreign Agent, thereby facilitating communication between the node and one of the Foreign Agents via the dummy interface IP address.
According to one embodiment, an interface of each of the Foreign Agents is associated with the same MAC address.
According to another embodiment, an interface of each of the Foreign Agents is associated with a different MAC address.
Upon completion of the proxy registration, the Foreign agent may update the node with the MAC address of the default gateway through a gratuitous ARP where the Foreign Agents are associated with different MAC addresses