Mobility support services using mobility aware access networks

• US 6,407,988 B1
• Filed: 10/06/1998
• Issued: 06/18/2002
• Est. Priority Date: 10/06/1998
• Status: Expired due to Fees

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Agraharam, Sanjay, Hodic, Michael W., Ramamurthy, Ram S., Roy, Radhika R., Shur, David Hilton
• Primary Examiner(s): TON, DANG T
• Application Number:
  US09/166,805
• Time in Patent Office: 1,351 Days
• Field of Search: 370/328, 370/351, 370/352, 370/401, 370/402, 370/403, 370/465, 370/474, 370/311, 370/389, 370/390, 370/399, 370/400, 704/228, 709/229, 709/228, 709/227, 713/200, 713/201, 713/202, 379/230, 379/221.08, 379/231, 379/232, 379/234, 379/240, 379/242, 379/220.01, 379/219, 455/422, 455/450, 455/437, 455/436, 455/439, 455/440, 455/442, 455/455, 455/456, 455/457, 455/555, 455/554, 455/560
• US Class Current: 370/328
• CPC Class Codes: H04W 12/03 Protecting confidentiality, e.g. by encryption
• CPC Class Codes: H04W 8/065 involving selection of the user mobility server
• CPC Class Codes: H04W 8/082 for traffic bypassing of mobility servers, e.g. location registers, home PLMNs or home agents
• CPC Class Codes: H04W 8/20 Transfer of user or subscriber data
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 88/182 Network node acting on behalf of an other network entity, e.g. proxy

Abstract

A mobility support technique provides home agents and foreign agents in mobility aware access networks. Participating mobile hosts are assigned a home address that is used by other hosts as the mobile host'"'"'s address. The home address actually addresses the home agent provided in the mobility aware access network. The home address provides additional privacy to the mobile host because it does not identify the mobile host'"'"'s home premises network where the mobile host resides permanently absent any mobility of the mobile host. By providing home agents and foreign agents in a mobility aware access network, the agents may cooperatively establish optimal routing paths for data transmitted to a mobile host. The agents may identify a pseudo home agent, an agent in a mobility aware access network located near to a transmitting mobile host, that acts as the home agent of a destination mobile host. The pseudo home agent tunnels data directly to the destination mobile host without requiring the data to be routed first to the true home agent. In this regard, the pseudo home agent establishes a more direct routing path between the transmitting and destination mobile hosts.

Claims

1. A method of providing mobility support to a mobile host, comprising, responsive to data received at a home agent:

tunneling the data to a foreign agent at a care-of-address of the mobile host,

identifying an address of a correspondent host that originated the data,

identifying a network associated with the correspondent host,

determining whether the identified network includes its own home agent, and

if the identified network includes a home agent, transferring the home address to the identified network'"'"'s home agent, the identified network'"'"'s home agent to be established as a pseudo home agent.

2. The method of claim 1, wherein the transferring step includes a step of providing the mobile host'"'"'s home address to the identified network'"'"'s home agent.

3. The method of claim 1, wherein the identified network'"'"'s home agent tunnels subsequent data originated by the correspondent host and addressed to the home address to the care-of-address.

4. The method of claim 1, further comprising, prior to the tunneling:

retrieving a host profile related to the mobile host,

determining whether the host profile identifies a currently visited network for the mobile host, and

if so, identifying a foreign agent based on the currently visited network, and

if the mobile host is registered in a foreign network, identifying a care-of address associated with the foreign network.

5. In a computer network, a method of optimizing routing of data from a correspondent host to a mobile host, the mobile host having been assigned a home address that actually addresses a home agent in a first access network and having registered with a foreign agent, the correspondent host located in a premises network associated with a second access network, the method comprising:

in the first access network;

receiving at the home agent data addressed to the home address,

identifying an address of the correspondent host,

identifying the second access network based upon the address of the correspondent host,

identifying an agent in the second access network to be established as a pseudo home agent, and

providing the home address to the pseudo home agent; and

in the second access network;

routing subsequent data received from the correspondent host that is addressed to the home address to the pseudo home agent, and

tunneling the subsequent data from the pseudo home agent to the foreign agent.

6. In a computer network, a method of optimizing routing of data from a correspondent host to a mobile host, the mobile host having registered with a foreign agent and having been assigned a home address that actually addresses a home agent in a first access network, the correspondent host located in a premises network associated with a second access network, the method comprising:

receiving at the home agent data addressed to the home address,

identifying an address of the correspondent host,

identifying the second access network based upon the address of the correspondent host,

identifying an agent in the second access network to be established as a pseudo home agent, and

providing the home address to the pseudo home agent.

7. The method of claim 6, further comprising:

thereafter, in the second access network, routing subsequent data received from the correspondent host that is addressed to the home address to the pseudo home agent, and

tunneling the subsequent data from the pseudo home agent to the foreign agent.

8. The method of claim 6, further comprising configuring the second network to route data addressed to the home address to the pseudo home agent.

9. In a computer network, a mobility support method for a mobile host, the mobile host having been assigned a home address representing a home agent in a first access network, the mobile host having registered in a foreign premises network and having been assigned a care of address by a foreign agent in an access network associated with the foreign premises network, the method comprising:

receiving at the home agent data addressed to the home address,

retransmitting the data to the foreign agent,

identifying an address of the correspondent host,

identifying the second access network based upon the address of the correspondent host,

identifying an agent in the second access network to be established as a pseudo home agent, and

providing the home address to the pseudo home agent.

10. A mobility support method, comprising, in an access network:

routing first data from a correspondent host addressed to a home address of a mobile host, the correspondent host being a member of the access network,

receiving a recruitment message from a first home agent, the home agent being associated with the mobile host, the recruitment message identifying a care-of-address associated with the mobile host,

responsive to the recruitment message, routing second data from the correspondent host addressed to the home address of the mobile host to a second home agent, the second home agent being a member of the access network, and

tunneling the second data to a foreign agent at the care-of-address.

11. The mobility support method of claim 10, further comprising:

responsive to an error message from the foreign agent, updating the care-of-address of the mobile host, and

tunneling the second data to another foreign agent at the updated care-of-address.

12. A method of providing mobility support to a mobile host, comprising, responsive to data received at a first home agent:

tunneling the data to a foreign agent at a care-of-address of the mobile host,

identifying an access network associated with a correspondent host that originated the data,

determining whether the access network includes its own home agent, and

if the access network'"'"'s home agent is different from the first home agent, transferring the home address to the access network'"'"'s home agent, the access network'"'"'s home agent to be established as a pseudo home agent.

13. The method of claim 12, wherein the transferring step includes a step of providing the mobile host'"'"'s home address to the access network'"'"'s home agent.

14. The method of claim 12, wherein the access network'"'"'s home agent tunnels subsequent data originated by the correspondent host and addressed to the home address to the care-of-address.

15. The method of claim 12, further comprising, prior to the tunneling:

retrieving a host profile related to the mobile host,

determining whether the host profile identifies a currently visited network for the mobile host, and

if so, identifying a foreign agent based on the currently visited network, and

if the mobile host is registered in a foreign network, identifying a care-of address associated with the renetwork.