Patent ID: 8086210

Claim:
A method for handing-off a mobile node (MN) from one network interface to another network interface, the network interfaces being connected to a same layer 2 (L2) network, the method comprising: detecting at least two network interface cards (NICs) of the MN that are connected to the same L2 network; making a handover decision to hand-off a data flow of the MN from a first of the at least two NICs to a second of the at least two NICs; updating L2 information about the MN in one or more related network entities connected to the same L2 network so as to perform seamless handover without changing an address on layer 3 (L3) or higher layers requesting, from an internet protocol address manager (IPAM), a first assignment of an IP address to the MN when the MN enters the L2 network for a first time, wherein the IPAM is a dynamic host configuration protocol (DHCP) server; informing, by the MN, the IPAM of information on other NICs connected to the MN, storing, by the IPAM, the information; detecting MN NICs already connected to the L2 network based on the stored information: and performing a handshake protocol between the MN and the DHCP server, the handshake protocol including: receiving at the DHCP server a request message containing a list of medium access control (MAC) L2 addresses of installed NICs; storing in a database accessible by the DHCP server the list of L2 addresses; generating, by the MN, a new DHCP request message containing an updated list of L2 addresses, if the list of L2 addresses available on the MN changes; sending the updated list to the DHCP Server, wherein the DHCP server then updates the L2 address list in the database and answers with a DHCP acknowledgement message to the MN; when an additional NIC of the MN gets connected to the same L2 network, starting, by the MN, the handshake protocol with the DHCP server; sending to the DHCP server a DHCP discover message containing the L2 address of the additional NIC for which a new IP address should be configured; searching, by the DHCP server, the database for the L2 address contained in the DHCP discover message, wherein other information about the MN contained in the DHCP discover message may additionally be used for the search in the database; if the search succeeds, replying to the MN with a first DHCP reply message containing a flag indicating that the IP address of the DHCP discovery message has already been provided; then sending, by the DHCP server, to the MN a second DHCP reply message with a new flag indicating that the additional NIC of the MN is connected to the same L2 network as other NICs of the MN, wherein the L2 address of the other NICs are provided in the message as well as the IP address of the MN; arriving at a determination, by the MN using the second DHCP reply message, to remain in the same L2 network; and performing a L2 handover between different NICs of the MN.