Locator lookup-based, low-latency, multi-access IP mobility

A method for a system having a tree structure comprising a root node connected to a plurality of leaf nodes via a plurality of intermediate nodes, wherein:

• each leaf node and each intermediate node has a corresponding parent node in the tree structure;
• and
• the root node and each intermediate node has at least one corresponding child node in the tree structure, the method comprising:
• a first leaf node communicating with a destination endpoint via a first access network, wherein the first leaf node stores a first mapping from a permanent virtual IP (VIP) address for the destination endpoint to a first physical IP (PIP) address for the destination endpoint on the first access network;
• a second leaf node communicating with the destination endpoint via a second access network different from the first access network, wherein the second leaf node stores a second mapping from the VIP address for the destination endpoint to a second PIP address for the destination endpoint on the second access network, the second PIP address being different from the first PIP address;
• the root node stores (i) a first root-node pointer pointing to a first intermediate node for the destination endpoint and the first access network and (ii) a second root-node pointer pointing to either the first intermediate node or a different intermediate node for the destination endpoint and the second access network;
• and
• the first intermediate node stores at least a first intermediate-node pointer to a first child node for the destination endpoint and the first access network, wherein the first intermediate node uses at least the first intermediate-node pointer to forward, towards the destination endpoint, a connection setup request (CSR) for the destination endpoint received from a corresponding node.

A destination endpoint comprising:

• a first interface configured to communicate via a first access network with a first leaf node of a system having a tree structure;
• and
• a second interface configured to communicate via a second access network, different from the first access network, with a second leaf node of the system, different from the first leaf node, wherein:
• the destination endpoint is configured to receive, at the first interface, a first copy of a connection setup request (CSR) transmitted by a corresponding node to the system and then transmitted by the first leaf node to the destination endpoint;
• and
• the destination endpoint is configured to receive, at the second interface, a second copy of the CSR transmitted by the second leaf node to the endpoint.