Q28,paper 2,june12 . Mobile IP provides two basic functions.

Options (A) Route discovery and registration (B) Agent discovery and registration (C) IP binding and registration (D) None of the above
Answer (B) Agent discovery and registration.
Explanation.
Mobile IP uses two IP addresses: Home address: The IP address assigned to the mobile node, making it logically appear attached to its home network. Care-of address: An IP address at the mobile node's current point of attachment to the Internet, when the mobile node is not attached to the home network.
Following are the agents
Home agent: A router on the home network that effectively causes the mobile node to be reachable at its home ad-dress even when the mobile node is not attached to its home network. Foreign agent: A router on the foreign network that can assist the mobile node in receiving datagrams delivered to the care-of address. Mobile ip works by discovering the care of address by agent advertisement, registering the care of address and tunneling the packets to COA.
Agent Advertisement: HA and FA periodically send advertisement messages into their Subnets.MN reads a COA from the FA advertisement messages. MN signals COA to the HA via the FA, HA acknowledges before the registration.