Secure candidate access router discovery method and system
Security mechanisms are disclosed that protect the integrity of the candidate access node discovery procedures in a mobile communication network. In accordance with an aspect of the invention, an access node stores information on candidate access nodes in the mobile communication network and updates the information only after verifying information provided by a mobile terminal after a handoff from one access node to another access node. In accordance with another aspect of the invention, the information on candidate access nodes in the mobile communication network are associated with a particular mobile terminal and stored at the mobile terminal in a candidate access node list.
1. A method of secure discovery of access nodes in a mobile communication network comprising the steps of:
providing a mobile terminal with information from a first access node prior to handoff to a second access node;
after handoff of the mobile terminal to the second access node, providing the second access node with information from the mobile terminal, wherein the information from the mobile terminal comprises information from the first access node;
receiving at the first access node a message from the second access node requesting verification of the information provided by the mobile terminal to the second access node;
verifying the information provided by the mobile terminal to the second access node before updating information on candidate access nodes in the mobile communication network; and,
comparing a delay to a configurable threshold value, wherein the delay comprises a difference between a current system time minus a time at which the first access node provides the information to the mobile terminal minus a stay time.
2. The method of claim 1 wherin the information of candidate access nodes in the mobile communication network is recorded in a candidate access node table that is shared among mobile terminals in the mobile communication network.
3. The method of claim 1 wherein the information from the first access node comprises a network address of the first access node.
4. The method of claim 1 wherein the information provided by the mobile terminal to the second access node comprises a ticket generated by the first access node for the mobile terminal.
5. The method of claim 1 wherein timestamps recorded by the first access node and the second access node are utilized to measure the delay.
6. The method of claim 1 wherein the information provided by the mobile terminal to the second access node comprises an identifier for the mobile terminal and wherein the information is further verified by checking whether the mobile terminal that provided the information to the second access node is the same mobile terminal that communicated with the first access node prior to handoff.
7. The method of claim 1 wherein the message from the second access node is authenticated.
8. The method of claim 1 wherein a limit is placed on a number of messages received by the second access node from the mobile terminal prior to verifying the information provided by the mobile terminal to the second access node.
9. The method of claim 1 wherein the mobile terminals are Internet Protocol (IP) devices and wherein the access nodes are IP routers.
10. The method of claim 1 wherein the message from the second access node comprises a physical (MAC) address of the first acces node.
11. An access node comprising memory for storing information on candidate access nodes in a mobile communication network and a processor that executes device-readable instructions for performing the steps of:
providing a mobile terminal with information from the access node prior to handoff to a second access node;
after handoff of the mobile terminal to the second access node, receiving a message from the second access node requesting verification of information provided by the mobile terminal to the second access node, wherein the information provided by the mobile terminal to the second access node comprises information from the access node; and,
verifying the information provided by the mobile terminal to the second access node before updating information on candidate access nodes in the mobile communication network; and,
comparing a delay to a configurable threshold value, wherein the delay comprises a difference between a current system time minus a time at which the first access node provides the information to the mobile terminal minus a stay time.
12. The access node of claim 11 wherein the information provived by the mobile terminal to the second access node comprises a ticket generated by the access node for the mobile terminal.
13. The access node of claim 12 wherein the information provided by the mobile terminal to the second access node comprises an identifier for the mobile terminal and wherein the information is further verified by checking whether the mobile terminal that provided the information to the second access node is the same mobile terminal that communicated with the access node prior to handoff.
14. The access node of claim 12 wherein the message from the second access node is authenticated.
15. The access node of claim 12 wherein the access node further comprises an Internet Protocol (IP) routing circuit.
16. The method of claim 12 wherein the message from the second access node comprises a physical (MAC) address of the first access node.
17. A mobile terminal comprising memory and a handoff processing circuit that performs the steps of:
prior to handoff to a second access node, receiving information from a first access node and a ticket generated by the first access node;
storing the ticket and the information from the first access node in the memory;
after handoff to a second access node, providing the ticket and the information from the first access node to the second access node, so that the second access node can verify the ticket with the first access node prior to updating information on candidate access nodes in a mobile communication network;
wherein the ticket is utilized by the first and second access nodes to compare a delay to a configurable threshold value, wherein the delay comprises the difference of a current system time minus a time at which the ticket was generated minus a stay time.
18. The mobile terminal of claim 17 wherein the ticket comprises an identifier for the mobile terminal and wherein the ticket is further verified by checking whether the mobile terminal that provided the information to the second access node is the same mobile terminal that communicated with the first access node prior to handoff.
19. The method of claim 1 wherein the message from the second access node comprises a physical (MAC) address of the first access node.