LIN6 is a protocol supporting mobility and multi-homing in IPv6. LIN6 introduces the node id, not the interface id, for each node. Each node can be identified by its node id no matter where the node is connected and no matter how many interfaces the node has. In the IPv6 layer, 64-bit node id called LIN6 ID is used while 128-bit node-id called LIN6 generalized ID is used above the Transport layer. TCP connections and security associations can be preserved even if the node moves to another subnet or the node changes the using interface in a multi-homing environment without modifying TCP or IPsec. In comparison with Mobile IPv6, LIN6 has several advantages in terms of header overhead and fault tolerance.