Single phase local mobility scheme for wireless access to packet-based networks

• US 7,239,618 B1
• Filed: 12/11/1998
• Issued: 07/03/2007
• Est. Priority Date: 12/11/1998
• Status: Expired due to Fees

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Murakami, Kazutaka, Ramjee, Ramachandran, Varadhan, Kannan, La Porta, Thomas F., Thuel, Sandra R.
• Primary Examiner(s): Vu; Huy D.
• Assistant Examiner(s): DUONG, DUC T
• Application Number:
  US09/210,213
• Time in Patent Office: 3,126 Days
• Field of Search: 370/331, 370/338, 370/392, 370/400, 370/401, 370/402, 370/403, 370/404, 455435-437, 455/445
• US Class Current: 370/331
• CPC Class Codes: H04L 2101/604 Address structures or formats
• CPC Class Codes: H04L 61/10 of different types
• CPC Class Codes: H04L 61/5007 Internet protocol [IP] addresses
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]
• 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: H04L 9/40 Network security protocols
• CPC Class Codes: H04W 36/04 Reselecting a cell layer in multi-layered cells
• CPC Class Codes: H04W 8/087 for preserving data network PoA address despite hand-offs
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

Local mobility within a subnet is supported by classifying wireless base stations, and the routers used to forward packets to those base stations, within defined domains. Domains are defined to incorporate a subnet having a plurality of base stations. Base stations are used by mobile devices to attach to the wired portion of a packet-based network, such as the Internet, and exchange packets thereover with a correspondent node. Packets sent from the correspondent node to the mobile device have a packet destination address corresponding to the mobile device. The mobile device retains this address for the duration of time it is powered up and attached to the Internet via any base station within a given domain. Host-based routing is utilized to update routing table entries corresponding to the mobile device at routers incorporated within a single domain. The routing table entries are established and updated via path setup schemes to convey packets destined for the mobile device along the proper established path through the domain routers and base stations, regardless of the domain base station through which the mobile device is attached. Path setup schemes utilize power up, refresh, and handoff path setup messages to maintain the proper relationship between router interfaces and packet addresses for routing table entries.

Claims

1. A method of establishing a routing path in a distributed packet-based network for packet delivery to a destination node within the same packet-based subnet, said destination node having a destination node address, wherein a first address for delivery of a plurality of packets is assigned to a wireless device in said subnet, said first address utilized when said wireless device is attached to said packet-based network through a base station included within a first domain including a set of identified nodes, and wherein a home agent utilizes a second address for said wireless device when said wireless device is attached to the packet-based network through a base station excluded from said first domain, said method comprising the steps of:

launching a path setup message from said destination node;

receiving said path setup message over a first interface at a first router;

and creating a first routing table entry for a first routing table, said first routing table entry corresponding said destination node address to said first interface, wherein a packet, subsequently received at said first router and having said destination node address as a packet header destination address, is forwarded from said first router over said first interface after said first router associates said destination node address with said first routing table entry, and

forwarding a handoff update path setup message, for handoffs processed at a network layer, from a second wireless base station to a first wireless base station if said wireless device is handed off from said first wireless base station to said second wireless base station, said handoff update path setup message used to alter routing table entries for selected routers of said subnet, and wherein said first address for said wireless device continues to be utilized if said second base station is within the same subnet.

2. The method in accordance with claim 1 wherein said destination node is a wireless device.

3. The method in accordance with claim 2 wherein said first router is incorporated within a first wireless base station.

4. The method in accordance with claim 3 wherein said wireless device is able to simultaneously tune to, and receive packets from, greater than one base station.

5. The method in accordance with claim 4 wherein said wireless device is a CDMA device.

6. The method in accordance with claim 1 wherein said plurality of subnet routers include at least said first wireless base station and said second wireless base station.

7. The method in accordance with claim 1 wherein said handoff update path setup message is initiated from said wireless device.

8. The method in accordance with claim 1 wherein said packet based subnet is an Internet Protocol subnet.

9. The method in accordance with claim 1 further comprising the steps of:

forwarding said path setup message to a next router, said next router receiving said path setup message over a first interface at said next router;

creating a next routing table entry for a next routing table, said next routing table entry corresponding said destination node address to said first interface at said next router; and

sending a path setup message acknowledgment to said destination node address if said next router is a subnet root router.

10. The method in accordance with claim 9 further comprising the step of:

repeating said steps of forwarding and creating a next routing table entry if said next router is not said subnet root router.

11. The method in accordance with claim 1 further comprising the step of:

maintaining said first routing table entry as a soft state in said first router, said first routing table entry overwritten with a default entry if a refresh path setup message is not received at said router within a specified period of time.

20. The method of claim 1, wherein said subnet is a single hop wireless network.

12. A packet router having a routing table adapted to maintain a plurality of routing table entries for a distributed packet-based network for packet delivery to a destination node within the same packet-based subnet, said destination node having a destination node address, wherein a first address for delivery of a plurality of packets is assigned to a wireless device in said subnet, said first address utilized when said wireless device is attached to said packet-based network through a base station included within a first domain including a set of identified nodes, and wherein a home agent utilizes a second address for said wireless device when said wireless device is attached to the packet-based network through a base station excluded from said first domain, said packet router comprising:

means for receiving a path setup message over a first interface, said path setup message including a field defining a destination address;

means, responsive to receiving said destination address, for generating a routing table entry corresponding packets arriving at said packet router and having said destination address as a packet header destination address to said first interface;

means for receiving at least one packet having said destination address as said packet header destination address;

means for performing a lookup of said routing table entry having said destination address and as said packet header destination address from said plurality of routing table entries;

means, responsive to said lookup, for forwarding said at least one packet over said first interface,

wherein a handoff update path setup message from a second wireless base station to said router, for handoffs processed at a network layer, is received if said wireless device is handed off from said router to said second wireless base station, said handoff update path setup message used to alter routing table entries for selected routers of said subnet, and wherein said first address for said wireless device continues to be utilized if said second base station is within the same subnet.

13. The packet router in accordance with claim 12 wherein said destination address corresponds to a wireless device.

14. The packet router in accordance with claim 12 wherein said router is incorporated in a wireless base station.

15. The packet router in accordance with claim 12 wherein said packet router is an Internet Protocol router.

16. The packet router in accordance with claim 12 wherein said path setup message is a power up path setup message.

17. The packet router in accordance with claim 12 wherein said path setup message is a handoff path setup message.

18. The packet router in accordance with claim 12 wherein said path setup message is a refresh path setup message.

19. A method of updating host based routing table entries for a plurality of routers within a subnet when a mobile device is handed off from a first wireless base station to a second wireless base station, said subnet providing wireless access for said mobile device to a packet based network, wherein a first address for delivery of a plurality of packets is assigned to a wireless device in said subnet, said first address utilized when said wireless device is attached to said packet-based network through a base station included within a first domain including a set of identified nodes, and wherein a home agent utilizes a second address for said wireless device when said wireless device is attached to the packet-based network through a base station excluded from said first domain, said method comprising the steps of:

creating a handoff path setup message, for handoffs processed at a network layer, at said mobile device;

routing said handoff path setup message to said first wireless base station;

relating, as a routing table entry, an address for said mobile device with an interface over which said handoff path setup message is received at said first wireless base station and each intermediate router and base station through which said handoff path setup message is routed; and

utilizing said routing table entry to forward a packet having said address for said mobile device as a packet header destination address over said interface over which said handoff path setup message is received, and wherein said first address for said wireless device continues to be utilized if said second base station is within the same subnet.