Handover method and radio base station

A handover method in which a mobile station performs processing for handover from a handover-source radio base station to a handover-target radio base station, the handover method comprising the steps of:

• forwarding, at the handover-source radio base station, first user data for the mobile station to the handover-target radio base station when it is determined that the handover processing is to be performed, the first user data being stored in the handover-source radio base station;
• forwarding, at the handover-target radio base station, the first user data to the mobile station;
• activating, at the handover-target radio base station, a predetermined timer when transmitting a path switch request to a path control apparatus to request switch of a path for forwarding user data, and storing second user data for the mobile station received from the path control apparatus until the predetermined timer expires;
• and
• forwarding, at the handover-target radio base station, the stored second user data to the mobile station after the predetermined timer expires.