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 8,059,661 B2
• Filed: 12/29/2004
• Issued: 11/15/2011
• 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
• Primary Examiner(s): Wilson; Robert
• Application Number:
  US11/027,466
• Publication Number:
  US 20060140164A1
• Time in Patent Office: 2,512 Days
• Field of Search: None
• US Class Current: 370/395.54
• 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. A Customer Premises Edge router, comprising:

a plurality of ports;

a memory storing therein instructions;

a processor that, when executing the instructions, performs the following steps;

processing a DHCP reply including a network prefix to obtain the network prefix, wherein the DHCP reply has been received from a DHCP server via one of the plurality of ports in response to a DHCP request, wherein the network prefix is owned by a Home Agent, wherein the DHCP reply does not include an IP address;

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

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

2. The Customer Premises Edge Router as recited in claim 1, wherein assigning is not performed prior to receiving the DHCP reply including the network prefix.

3. The Customer Premises Edge Router as recited in claim 1, wherein the nodes are associated with the Home Agent.

4. The Customer Premises Edge Router as recited in claim 1, wherein the Home Agent receives the DHCP request and transmits the DHCP reply to the Customer Premises Edge router.

5. An apparatus, comprising:

a plurality of ports;

a memory storing therein instructions;

a processor that, when executing the instructions, performs the following steps;

processing a DHCP reply including a network prefix to obtain the network prefix, wherein the DHCP reply has been received from a DHCP server via one of the plurality of ports in response to a DHCP request;

dividing the network prefix among the plurality of ports of the apparatus;

assigning a home address based upon dividing the network prefix to one or more nodes on the plurality of ports, wherein the nodes support Mobile IP, wherein the network prefix is owned by a Home Agent; and

sending an advertisement which is forwarded from each of the plurality of ports, the advertisement including at least one of a network prefix associated with a corresponding port of the plurality of ports or 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 port.

6. The apparatus as recited in claim 5, wherein the Home Agent is coupled to the DHCP server.

7. The apparatus as recited in claim 5, wherein the Home Agent is implemented in the DHCP server.

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

9. The apparatus as recited in claim 5, wherein the processor, when executing the instructions, performs further steps, comprising:

identifying a Home Agent associated with the network prefix.

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

obtaining the Home Agent address from the DHCP reply.

11. The apparatus as recited in claim 5, wherein the processor, when executing the instructions, performs further steps, comprising:

intercepting packets addressed to nodes on the plurality of ports of the apparatus.

12. The apparatus as recited in claim 11, wherein the processor, when executing the instructions, performs further steps comprising:

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

13. An apparatus, comprising:

a plurality of ports;

a memory storing therein instructions;

a processor that, when executing the instructions, performs the following steps;

processing a DHCP reply including a network prefix to obtain the network prefix, wherein the DHCP reply has been received from a DHCP server via one of the plurality of ports in response to a DHCP request;

dividing the network prefix among the plurality of ports;

assigning a home address based upon dividing the network prefix to one or more nodes on the plurality of ports, wherein the nodes support Mobile IP, wherein the network prefix is owned by a Home Agent;

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.

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

15. The apparatus as recited in claim 13, wherein the new location is a MAC address associated with one of the plurality of ports of the apparatus.

16. An apparatus, comprising:

a plurality of ports;

a memory storing therein instructions;

a processor that, when executing the instructions, performs the following steps;

processing a DHCP reply including a network prefix to obtain the network prefix, wherein the DHCP reply has been received from a DHCP server via one of the plurality of ports in response to a DHCP request;

dividing the network prefix among the plurality of ports of the apparatus;

assigning a home address based upon dividing the network prefix to one or more nodes on the plurality of ports, wherein the nodes support Mobile IP, wherein the network prefix is owned by a Home Agent;

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; 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.

17. The apparatus as recited in claim 16, wherein the processor, when executing the instructions, performs further steps 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.

18. The apparatus as recited in claim 16, wherein 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 apparatus within a predetermined period of time.

19. The apparatus as recited in claim 16, wherein the neighbor solicitation includes at least one of a network prefix or a global address of the one of the plurality of nodes that has attempted to register with the Home Agent.

20. The apparatus as recited in claim 19, wherein the processor, when executing the instructions, performs further steps comprising:

comparing the network prefix or the global address with network prefixes supported by the apparatus;

wherein sending the neighbor solicitation comprises sending the neighbor solicitation to one of the network prefixes supported by the apparatus corresponding to the network prefix or the global address.

21. The apparatus as recited in claim 16, 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.

22. The apparatus as recited in claim 16, wherein the processor, when executing the instructions, performs further steps comprising:

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

23. The apparatus as recited in claim 22, wherein the processor, when executing the instructions, performs further steps comprising:

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

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

means for receiving a DHCP 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;

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, wherein the network prefix is owned by a Home Agent; and

means for 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 or 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.

25. A system supporting Mobile IP for distributing network prefixes in a network device, comprising:

a plurality of ports;

a memory storing therein instructions;

a processor that, when executing the instructions, performs the following steps;

processing a DHCP reply including a network prefix to obtain the network prefix, wherein the DHCP reply has been received from a DHCP server in response to a DHCP request;

dividing the network prefix among a plurality of ports of the network device;

assigning a home address based upon the divided network prefix to one or more nodes on the plurality of ports, wherein the nodes support Mobile IP, wherein the network prefix is owned by a Home Agent;

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.

26. The system as recited in claim 25, wherein the network prefix is owned by a Home Agent.

27. The system as recited in claim 26, wherein the Home Agent receives the DHCP request and transmits the DHCP reply to the Customer Premises Edge router.

28. A non-transitory computer-readable storage medium storing thereon computer-readable instructions for distributing network prefixes by a Customer Premises Edge router in a system supporting Mobile IP by performing steps comprising:

processing a DHCP reply received from a DHCP server in response to a DHCP request, the DHCP reply including a network prefix, wherein the DHCP reply does not include an IP address;

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

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, wherein the network prefix is owned by a Home Agent;

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; and

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.

29. A non-transitory computer-readable storage medium storing thereon computer-readable instructions by performing steps comprising:

obtaining a network prefix from a DHCP reply including the network prefix by a router, wherein the DHCP reply does not include an IP address;

dividing the network prefix by the router to generate a plurality of network prefixes;

associating each of the plurality of network prefixes with a corresponding one of the plurality of interfaces of the router such that a different network prefix is associated with each of the plurality of interfaces; and

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

30. The non-transitory computer-readable storage medium as recited in claim 29, wherein the network prefix is owned by a Home Agent supporting Mobile IP.

31. The non-transitory computer-readable storage medium as recited in claim 29, wherein the router is a Customer Premises Edge Router.

32. The non-transitory computer-readable storage medium as recited in claim 29, wherein the router is not in a home network of the nodes.

33. An apparatus, comprising:

a plurality of ports;

a memory storing therein instructions;

a processor that, when executing the instructions, performs the following steps;

processing a DHCP reply including a network prefix to obtain the network prefix, wherein the DHCP reply has been received via one of the plurality of ports, wherein the DHCP reply does not include an IP address;

dividing the network prefix to generate a plurality of network prefixes;

associating each of the plurality of network prefixes with a corresponding one of the plurality of ports such that a different network prefix is associated with each of the plurality of ports and

assigning a home address to one or more nodes on one of the plurality of ports based upon the one of the plurality of network prefixes associated with the one of the plurality of ports, wherein the nodes support Mobile IP.

34. The apparatus as recited in claim 33, wherein the network prefix is owned by a Home Agent supporting Mobile IP.

35. A method, comprising:

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

dividing the network prefix among a plurality of interfaces of the network device;

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, wherein the network prefix is owned by a Home Agent; and

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 or 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.

36. The method as recited in claim 35, further comprising:

identifying a Home Agent associated with the network prefix.

37. The method as recited in claim 36, wherein identifying the Home Agent associated with the network prefix comprises:

obtaining the Home Agent address from the DHCP reply.

38. The method as recited in claim 35, further comprising:

intercepting packets addressed to nodes on the plurality of interfaces of the network device.

39. The method as recited in claim 38, further comprising:

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

40. The method as recited in claim 35, wherein the network device is a Customer Premises Edge Router.

41. A method, comprising:

receiving a DHCP reply including a network prefix, wherein the DHCP reply does not include an IP address;

dividing the network prefix to generate a plurality of network prefixes;

associating each of the plurality of network prefixes with a corresponding one of a plurality of interfaces of a network device such that a different network prefix is associated with each of the plurality of interfaces; and

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

42. The method as recited in claim 41, wherein the network prefix is owned by a Home Agent supporting Mobile IP.

43. An apparatus, comprising:

means for receiving a DHCP reply including a network prefix, wherein the DHCP reply does not include an IP address;

means for dividing the network prefix to generate a plurality of network prefixes;

means for associating each of the plurality of network prefixes with a corresponding one of a plurality of interfaces of a network device such that a different network prefix is associated with each of the plurality of interfaces; and

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

44. A method, comprising:

receiving a DHCP 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 a network device;

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, wherein the network prefix is owned by a Home Agent;

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; 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.

45. The method as recited in claim 44, 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.

46. The method as recited in claim 44, wherein 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 network device within a predetermined period of time.

47. The method as recited in claim 44, wherein the neighbor solicitation includes at least one of a network prefix or a global address of the one of the plurality of nodes that has attempted to register with the Home Agent.

48. The method as recited in claim 44, 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.

49. The method as recited in claim 44, further comprising:

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