Methods and apparatus for implementing home agent redundancy

In a Home Agent, a method of maintaining Mobile IP operation, the method comprising:

• registering a mobile node;
• creating a registration entry for the Mobile Node in a mobility binding table;
• sending a multicast message to a virtual router group to which the Home Agent belongs and with which the Home Agent shares a virtual IP address, the multicast message notifying the virtual router group of the registration;
• determining whether an acknowledgement to the multicast message has been received from another Home Agent in the virtual router group;
• and
• when it is determined that an acknowledgement has not been received from the Home Agent in the virtual router group, retransmitting a message to the Home Agent notifying the Home Agent of the registration.

In a Home Agent, a method of maintaining Mobile IP operation, the method comprising:

• registering a mobile node;
• creating a registration entry for the Mobile Node in a mobility binding table;
• sending a multicast message to a virtual router group to which the Home Agent belongs and with which the Home Agent shares a virtual IP address, the multicast message notifying the virtual router group of the registration;
• and
• prior to registering a mobile node, sending a multicast mobility binding table request to the virtual router group indicating that bindings present in a mobility binding table maintained by one or more members of the virtual router group are requested.

In a Home Agent, a method of maintaining Mobile IP operation, the method comprising:

• registering a Mobile Node;
• creating a registration entry for the Mobile Node in a mobility binding table;
• sending a multicast message to a virtual router group to which the Home Agent belongs and with which the Home Agent shares a virtual IP address, the multicast message notifying the virtual router group of the registration;
• and
• receiving a multicast mobility binding table request from another Home Agent in the virtual router group, the multicast mobility binding table request being addressed to the virtual router group and indicating that bindings present in a mobility binding table maintained by members of the virtual router group are requested.

In a Home Agent, the Home Agent being a member of a redundancy group including one or more Home Agents, a method of providing Mobile IP redundancy, the method comprising:

• sending a multicast mobility binding table request to the redundancy group indicating that bindings present in a mobility binding table maintained by one or more members of the redundancy group are requested;
• receiving one or more reply messages including one or more bindings associated with one or more mobile nodes;
• updating a mobility binding table maintained by the Home Agent with the bindings received in the reply messages;
• receiving one or more reply messages including one or more Home Agent identifiers identifying Home Agents in the redundancy group;
• and
• updating a list of Home Agents in the redundancy group such that the list includes the Home Agent identifiers.

In a Home Agent, the Home Agent being a member of a redundancy group including one or more Home Agents, a method of providing Mobile IP redundancy, the method comprising:

• sending a multicast mobility binding table request to the redundancy group indicating that bindings present in a mobility binding table maintained by one or more members of the redundancy group are requested;
• receiving one or more reply messages including one or more bindings associated with one or more mobile nodes;
• updating a mobility binding table maintained by the Home Agent with the bindings received in the reply messages;
• and
• determining whether one or more Home Agents other than Home Agent are in the virtual router group prior to sending the multicast mobility binding table request.

In a Home Agent, the Home Agent being a member of a redundancy group including one or more Home Agents, a method of providing Mobile IP redundancy, the method comprising:

• sending a multicast mobility binding table request to the redundancy group indicating that bindings present in a mobility binding table maintained by one or more members of the redundancy group are requested;
• receiving one or more reply messages including one or more bindings associated with one or more mobile nodes;
• updating a mobility binding table maintained by the Home Agent with the bindings received in the reply messages;
• receiving a binding table update including a binding associated with a mobile node that has registered with another Home Agent;
• and
• updating the mobility binding table maintained by the Home Agent to include the binding.

In a Home Agent, the Home Agent being a member of a redundancy group including one or more Home Agents, a method of providing Mobile IP redundancy, the method comprising:

• sending a multicast mobility binding table request to the redundancy group indicating that bindings present in a mobility binding table maintained by one or more members of the redundancy group are requested;
• receiving one or more reply messages including one or more bindings associated with one or more mobile nodes;
• updating a mobility binding table maintained by the Home Agent with the bindings received in the reply messages;
• receiving a binding table update indicating that a specified mobile node is no longer registered with the another Home Agent;
• determining whether a binding exists in the mobility binding table maintained by the Home Agent for the specified mobile node;
• when it is determined that a binding exists in the mobility binding table maintained by the Home Agent for the specified mobile node, removing the binding from the mobility binding table;
• and
• when it is determined that a binding does not exist in the mobility binding table maintained by the Home Agent for the specified mobile node, creating an entry in the mobility binding table for the specified mobile node and marking the entry as deleted.

In a Home Agent, the Home Agent being a member of a redundancy group including one or more Home Agents, a method of providing Mobile IP redundancy, the method comprising:

• sending a multicast mobility binding table request to the redundancy group indicating that bindings present in a mobility binding table maintained by one or more members of the redundancy group are requested;
• receiving one or more reply messages including one or more bindings associated with one or more mobile nodes;
• updating a mobility binding table maintained by the Home Agent with the bindings received in the reply messages;
• receiving a multicast mobility binding table request from another Home Agent in the virtual router group, the multicast mobility binding table request being addressed to the virtual router group and indicating that bindings present in a mobility binding table maintained by members of the virtual router group are requested.

A computer-readable medium storing thereon computer-readable instructions executed by a computer for performing a method of maintaining Mobile IP operation in a Home Agent comprising:

• instructions for registering a Mobile Node with the Home Agent;
• instructions for creating a registration entry for the Mobile Node in a mobility binding table located at the Home Agent;
• instructions for sending a multicast message to a virtual router group to which the Home Agent belongs and with which the Home Agent shares a virtual IP address, the multicast message notifying the virtual router group of the registration;
• instructions for sending a multicast mobility binding table request to the virtual router group prior to registering a mobile node, the multicast mobility binding table request indicating that bindings present in a mobility binding table maintained by one or more members of the virtual router group are requested.

An apparatus for maintaining Mobile IP operation in a Home Agent, comprising:

• a processor;
• and
• a memory, at least one of the processor or the memory;
• registering a Mobile Node;
• creating a registration entry for the Mobile Node in a mobility binding table;
• sending a multicast message to a virtual router group to which the Home Agent belongs and with which the Home Agent shares a virtual IP address, the multicast message notifying the virtual router group of the registration;
• sending a multicast mobility binding table request to the virtual router group prior to registering a mobile node, the multicast mobility binding table request indicating that bindings present in a mobility binding table maintained by one or more members of the virtual router group are requested.

An apparatus for maintaining Mobile IP operation in a Home Agent, comprising:

• means for registering a Mobile Node;
• means for creating a registration entry for the Mobile Node in a mobility binding table;
• means for sending a multicast message to a virtual router group to which the Home Agent belongs and with which the Home Agent shares a virtual IP address, the multicast message notifying the virtual router group of the registration;
• and
• means for sending a multicast mobility binding table request to the virtual router group prior to registering a mobile node, the multicast mobility binding table request indicating that bindings present in a mobility binding table maintained by one or more members of the virtual router group are requested.

A computer-readable medium storing thereon computer-readable instructions executed by a computer for providing Mobile IP redundancy in a Home Agent, the Home Agent being a member of a redundancy group including one or more Home Agents, comprising:

• instructions for sending a multicast mobility binding table request at the Home Agent to the redundancy group indicating that bindings present in a mobility binding table maintained by one or more members of the redundancy group are requested;
• instructions for receiving one or more reply messages at the Home Agent including one or more bindings associated with one or more mobile nodes;
• instructions for updating a mobility binding table maintained by the Home Agent with the bindings received in the reply messages;
• and
• instructions for updating the mobility binding table maintained by the Home Agent to include a binding associated with a mobile node that has registered with another Home Agent, the binding being received via a binding table update.

An apparatus for providing Mobile IP redundancy in a Home Agent, the Home Agent being a member of a redundancy group including one or more Home Agents, comprising:

• a processor;
• and
• a memory, at least one of the processor the memory;
• sending a multicast mobility binding table request to the redundancy group indicating that bindings present in a mobility binding table maintained by one or more members of the redundancy group are requested;
• receiving one or more reply messages including one or more bindings associated with one or more mobile nodes;
• updating a mobility binding table maintained by the Home Agent with the bindings received in the reply messages;
• receiving a binding table update including a binding associated with a mobile node that has registered with another Home Agent;
• and
• updating the mobility binding table maintained by the Home Agent to include the binding.

An apparatus for providing Mobile IP redundancy in a Home Agent, the Home Agent being a member of a redundancy group including one or more Home Agents, comprising:

• means for sending a multicast mobility binding table request to the redundancy group indicating that bindings present in a mobility binding table maintained by one or more members of the redundancy group are requested;
• means for receiving one or more reply messages including one or more bindings associated with one or more mobile nodes;
• means for updating a mobility binding table maintained by the Home Agent with the bindings received in the reply messages;
• means for receiving a binding table update including a binding associated with a mobile node that has registered with another Home Agent;
• and
• means for updating the mobility binding table maintained by the Home Agent to include the binding.