Methods and apparatus for using DHCP for home address management of nodes attached to an edge device and for performing mobility and address management as a proxy home agent

• US 20060140164A1
• Filed: 12/29/2004
• Published: 06/29/2006
• Est. Priority Date: 12/29/2004
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Leung, Kent K., Patel, Alpesh
• Granted Patent: US 8,059,661 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04L 2101/668 Internet protocol [IP] address subnets
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]
• CPC Class Codes: H04L 61/5046 Resolving address allocation conflicts; Testing of addresses testing when self-assigning an address H04L61/5092
• CPC Class Codes: H04L 61/5061 Pools of addresses
• CPC Class Codes: H04L 61/5076 Update or notification mechanisms, e.g. DynDNS
• CPC Class Codes: H04L 61/5084 Providing for device mobility network addressing or numbering for mobility support in wireless networks H04W8/26; mobile IP H04W80/04
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

Methods and apparatus for supporting the management of mobility and addresses by a Customer Premises Edge (CPE) router in a Mobile IP environment are disclosed. When a network prefix is allocated by a DHCP router to the CPE router, the CPE router divides the network prefix among its interfaces, and allocates home addresses to Mobile Nodes connected to its interfaces, as appropriate. The CPE router also assists in performing Duplicate Address Detection (DAD) to ensure that a home address that has been allocated has not already been assigned to another node. Upon completion of registration of a Mobile Node that is connected to one of the interfaces of the CPE router with its Home Agent, the CPE router assists in routing traffic to the Mobile Node. In addition, the CPE router assists in notifying nodes when one of the Mobile Nodes has moved, as well as when one of the Mobile Nodes has de-registered with the Home Agent.

Claims

1. In a system supporting Mobile IP, a method of distributing network prefixes in a Customer Premises Edge router, comprising:

receiving a DHPC reply including a network prefix from a DHCP server in response to a DHCP request;

dividing the network prefix among a plurality of interfaces of the Customer Premises Edge router; and

assigning a home address based upon the divided network prefix to one or more nodes on the plurality of interfaces, wherein the nodes support Mobile IP.

2. The method as recited in claim 1, wherein the network prefix is owned by a Home Agent.

3. The method as recited in claim 2, wherein the Home Agent is coupled to the DHCP server.

4. The method as recited in claim 2, wherein the Home Agent is implemented in the DHCP server.

5. The method as recited in claim 2, wherein the Home Agent is implemented in a Cable Modem Termination System.

6. The method as recited in claim 2, wherein the Home Agent receives the DHCP request and transmits the DHCP reply to the Customer Premises Edge router.

7. The method as recited in claim 2, further comprising:

sending an advertisement from each of the plurality of interfaces, the advertisement including at least one of a network prefix associated with the corresponding interface and a Home Agent address of the Home Agent supporting the network prefix, thereby enabling the nodes to send a registration request or binding update to the Home Agent address when the network prefix provided in the advertisement is different from that of the home address of the nodes on that interface.

10. The method as recited in claim 1, further comprising:

intercepting packets addressed to nodes on the plurality of interfaces of the Customer Premises Edge router.

11. The method as recited in claim 10, further comprising:

forwarding the packets directly to the nodes or tunneling the packets to a Home Agent associated with the network prefix.

12. The method as recited in claim 2, further comprising:

receiving a neighbor advertisement from the Home Agent indicating that one of the nodes has roamed to a new location;

updating a proxy neighbor cache entry to indicate that the node has roamed to the new location; and

sending a neighbor advertisement to the plurality of nodes indicating that the node has roamed to the new location.

13. The method as recited in claim 12, wherein the new location is a care-of address.

14. The method as recited in claim 12, wherein the new location is a MAC address associated with one of the plurality of interfaces of the Customer Premises Edge router.

15. The method as recited in claim 2, further comprising:

sending a neighbor solicitation to one or more of the plurality of nodes, wherein the neighbor solicitation identifies at least one address of one of the plurality of nodes that has attempted to register with the Home Agent;

when a neighbor advertisement is received from one of the plurality of nodes, forwarding the neighbor advertisement to the Home Agent, thereby enabling the Home Agent to send an error message to the one of the plurality of nodes that has attempted to register with the Home Agent.

16. The method as recited in claim 15, further comprising:

receiving the neighbor solicitation from the Home Agent prior to sending the neighbor solicitation to the one or more of the plurality of nodes.

17. The method as recited in claim 15, wherein when a neighbor advertisement is not received from one of the plurality of nodes, the Home Agent determines that no duplicate address has been detected for one of the plurality of nodes that has attempted to register with the Home Agent when a neighbor advertisement is not received from the Customer Premises Edge router within a predetermined period of time.

18. The method as recited in claim 15, wherein the neighbor solicitation includes at least one of a network prefix and a global address of the one of the plurality of nodes that has attempted to register with the Home Agent

19. The method as recited in claim 18, further comprising:

comparing the network prefix or the global address with network prefixes supported by the Customer Premises Edge router;

wherein sending the neighbor solicitation comprises sending the neighbor solicitation to one of the network prefixes supported by the Customer Premises Edge router corresponding to the network prefix or the global address.

20. The method as recited in claim 15, wherein the neighbor solicitation includes a link local address of the one of the plurality of nodes that has attempted to register with the Home Agent.

21. The method as recited in claim 1, further comprising:

sending an advertisement from each of the plurality of interfaces indicating that the nodes are at home.

22. The method as recited in claim 21, further comprising:

setting an H bit in the advertisement prior to sending the advertisement from each of the plurality of interfaces.

8. The method as recited in claim 8, further comprising:

identifying a Home Agent associated with the network prefix.

9. The method as recited in claim 8, wherein identifying the Home Agent associated with the network prefix comprises:

obtaining the Home Agent address from the DHCP reply.

23. A method of performing duplicate address detection by a network device, comprising:

sending a neighbor solicitation to one or more of the plurality of nodes, wherein the neighbor solicitation identifies at least one address of one of the plurality of nodes that has attempted to register with a Home Agent; and

when a neighbor advertisement is received from one of the plurality of nodes, forwarding the neighbor advertisement to the Home Agent, thereby enabling the Home Agent to send an error message to the one of the plurality of nodes that has attempted to register with the Home Agent.

24. The method as recited in claim 23, wherein the network device is a Customer Premises Edge router.

25. The method as recited in claim 23, further comprising:

receiving the neighbor solicitation from the Home Agent prior to sending the neighbor solicitation to the one or more of the plurality of nodes.

26. The method as recited in claim 23, wherein when a neighbor advertisement is not received from one of the plurality of nodes, the Home Agent determines that no duplicate address has been detected for one of the plurality of nodes that has attempted to register with the Home Agent when a neighbor advertisement is not received from the Customer Premises Edge router within a predetermined period of time.

27. The method as recited in claim 23, wherein the neighbor solicitation includes at least one of a network prefix and a global address of the one of the plurality of nodes that has attempted to register with the Home Agent

28. The method as recited in claim 27, further comprising:

comparing the network prefix or the global address with network prefixes supported by the Customer Premises Edge router;

wherein sending the neighbor solicitation comprises sending the neighbor solicitation to one of the network prefixes supported by the Customer Premises Edge router corresponding to the network prefix or the global address.

29. A system supporting Mobile IP adapted for distributing network prefixes in a Customer Premises Edge router, comprising:

means for receiving a DHPC reply including a network prefix from a DHCP server in response to a DHCP request;

means for dividing the network prefix among a plurality of interfaces of the Customer Premises Edge router; and

means for assigning a home address based upon the divided network prefix to one or more nodes on the plurality of interfaces, wherein the nodes support Mobile IP.

30. A system supporting Mobile IP and adapted for distributing network prefixes in a Customer Premises Edge router, comprising:

a processor; and

a memory, at least one of the processor and the memory being adapted for;

receiving a DHPC reply including a network prefix from a DHCP server in response to a DHCP request;

dividing the network prefix among a plurality of interfaces of the Customer Premises Edge router; and

assigning a home address based upon the divided network prefix to one or more nodes on the plurality of interfaces, wherein the nodes support Mobile IP.

31. A computer-readable medium storing thereon computer-readable instructions for distributing network prefixes by a Customer Premises Edge router in a system supporting Mobile IP, comprising:

instructions for receiving a DHPC reply including a network prefix from a DHCP server in response to a DHCP request;

instructions for dividing the network prefix among a plurality of interfaces of the Customer Premises Edge router; and

instructions for assigning a home address based upon the divided network prefix to one or more nodes on the plurality of interfaces, wherein the nodes support Mobile IP.

32. A network device adapted for performing duplicate address detection, comprising:

means for sending a neighbor solicitation to one or more of the plurality of nodes, wherein the neighbor solicitation identifies at least one address of one of the plurality of nodes that has attempted to register with a Home Agent; and

means for forwarding the neighbor advertisement to the Home Agent when a neighbor advertisement is received from one of the plurality of nodes, thereby enabling the Home Agent to send an error message to the one of the plurality of nodes that has attempted to register with the Home Agent.

33. A network device adapted for performing duplicate address detection, comprising:

a processor; and

a memory, at least one of the processor and the memory being adapted for;

sending a neighbor solicitation to one or more of the plurality of nodes, wherein the neighbor solicitation identifies at least one address of one of the plurality of nodes that has attempted to register with a Home Agent; and

when a neighbor advertisement is received from one of the plurality of nodes, forwarding the neighbor advertisement to the Home Agent, thereby enabling the Home Agent to send an error message to the one of the plurality of nodes that has attempted to register with the Home Agent.

34. A computer-readable medium storing thereon computer-readable instructions for performing duplicate address detection by a network device, comprising:

instructions for sending a neighbor solicitation to one or more of the plurality of nodes, wherein the neighbor solicitation identifies at least one address of one of the plurality of nodes that has attempted to register with a Home Agent; and

instructions for forwarding the neighbor advertisement to the Home Agent when a neighbor advertisement is received from one of the plurality of nodes, thereby enabling the Home Agent to send an error message to the one of the plurality of nodes that has attempted to register with the Home Agent.