Home agent discovery upon changing the mobility management scheme

A second node in a core network system including a first node and the second node, wherein the first node is a home agent and is different from the second node, the second node comprising:

• a receiver which, in response to a mobile node switching from a network-based mobility management scheme to a client-based mobility management scheme, receives from the mobile node an Internet Key Exchange (IKEv2) request message to establish a security association between the mobile node and the second node, which is discoverable in the client-based mobility management scheme, wherein the IKEv2 request message includes a Network Access Identifier (NAI) of the mobile node having a network prefix assigned to the mobile node, and wherein the mobile node prior to switching to the client-based mobility management scheme is attached to the core network including the first node, which is supported in the network-based mobility management scheme and is selected for the mobile node, and
• a transmitter which, in response to the IKEv2 request message, transmits to the mobile node an IKEv2 response message including redirect information containing one of an IP address of the first node and hints, wherein the hints include at least one of an address prefix and a domain name and allow the mobile node to derive a valid address of the first node, the valid address including an anycast group address, a multicast group address, or a unicast address.

A method performed by a first node and a second node in a core network system, wherein the first node is a home agent and is different from the second node, the method comprising:

• the second node, in response to a mobile node switching from a network-based mobility management scheme to a client-based mobility management scheme, receiving from the mobile node an Internet Key Exchange (IKEv2) request message to establish a security association between the mobile node and the second node, which is discoverable in the client-based mobility management scheme, wherein the IKEv2 request message includes a Network Access Identifier (NAI) of the mobile node having a network prefix assigned to the mobile node, and wherein the mobile node prior to switching to the client-based mobility management scheme is attached to the core network including the first node, which is supported in the network-based mobility management scheme and is selected for the mobile node;
• the second node, in response to the IKEv2 request message, transmitting to the mobile node an IKEv2 response message including redirect information containing one of an IP address of the first node and hints, wherein the hints include at least one of an address prefix and a domain name and allow the mobile node to derive a valid address of the first node, the valid address including an anycast group address, a multicast group address, or a unicast address;
• the first node receiving an IP address registration request from the mobile node to register a new address with the first node to establish a new security association between he mobile node and the first node, to which the mobile node is redirected by the second node using one of the IP address of the first node and the hints contained in the redirect information;
• and
• the first node receiving a Mobile IP (MIPv6) Binding Update from the mobile node using the IP address of the first node contained in the redirect information.