METHOD AND APPARATUS FOR CONFIGURING A MOBILE NODE TO RETAIN A "HOME" IP SUBNET ADDRESS

• US 20080071890A1
• Filed: 11/21/2007
• Published: 03/20/2008
• Est. Priority Date: 10/02/2002
• Status: Active Grant

• Current Assignee: Alpesh Patel, Kent Leung, Robert Meier, Timothy Olson
• Original Assignee: Alpesh Patel, Kent Leung, Robert Meier, Timothy Olson
• Inventors: Leung, Kent, Patel, Alpesh, Olson, Timothy, MEIER, Robert
• Granted Patent: US 8,560,644 B2
• Time in Patent Office: Days
• US Class Current: 709/220
• 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: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

A method and implementation are disclosed for binding a mobile node to a subnet. The invention comprises steps and implementations for intercepting messages sent by a mobile node to a server, associating a predetermined subnet with the intercepted messages and forwarding the intercepted messages to the server. The invention intercepts reply messages sent by at least one server and selects reply messages that are associated with the predetermined subnet. The selected reply messages are forwarded to the mobile node, and reply messages that are not associated with the predetermined subnet are discarded.

Claims

1. An apparatus, comprising:

a proxy mobile Internet Protocol entity;

wherein the proxy mobile Internet Protocol entity is configured to intercept a Dynamic Host Configuration Protocol (DHCP) request message sent by a mobile node on a first subnet;

wherein the proxy mobile Internet Protocol entity is configured to insert data representative of a second subnet into the intercepted DHCP request message to request an Internet Protocol (IP) address associated with the second subnet;

wherein the proxy mobile Internet Protocol entity is configured to forward the intercepted DHCP request message with the data representative of the second subnet to at least one DHCP server;

wherein the proxy mobile Internet Protocol entity is configured to intercept a DHCP reply message sent by at least one DHCP server;

wherein the proxy mobile Internet Protocol entity is configured to select a DHCP reply message has a subnet identifier matching the second subnet; and

wherein the proxy mobile Internet Protocol entity is configured to forward the selected DHCP reply message to the mobile node.

2. The apparatus of claim 1, wherein the proxy mobile Internet Protocol entity is further configured to discard a DHCP reply message that has a subnet identifier that does not match the second subnet.

3. The apparatus of claim 1, wherein the proxy mobile Internet Protocol entity is further configured to insert a predetermined subnet selection option having a subnet field into the intercepted message, wherein the predetermined subnet selection option is used to request the server for a network address for a specific subnet;

and

wherein the proxy mobile Internet Protocol entity is further configured to add a subnet mask option request into a parameter request list option of the intercepted message.

4. The apparatus of claim 3, wherein the subnet field indicates the guest home subnet configured for the mobile node'"'"'s service selection identifier.

5. The apparatus of claim 3, wherein the subnet field indicates the current home subnet of the mobile node previously assigned to a home subnet.

6. The apparatus of claim 3, wherein the proxy mobile Internet Protocol entity is configured to read identification fields of the intercepted message to find a transaction identifier and a client identifier fields;

and

wherein the proxy mobile Internet Protocol entity is configured to store the transaction identifier and the client identifier in an internal table.

7. The apparatus of claim 6, further comprising:

wherein the proxy mobile Internet Protocol entity is further configured to compare the transaction identifier and client identifier fields of the reply message with the respective fields stored in the internal table;

wherein the proxy mobile Internet Protocol entity is further configured to forward the reply message to the mobile node responsive to the transaction identifier and client identifier, of the reply message matching the respective fields stored in the internal table and

wherein the proxy mobile Internet Protocol entity is further configured to discard the reply message responsive to the transaction identifier and client identifier not matching the respective fields stored in the internal table.

8. The apparatus of claim 1, wherein the proxy mobile Internet Protocol entity is configured to assign the mobile node to a local subnet at startup by default.

9. Logic encoded in one or more tangible media for execution, and when executed operable to:

intercept a Dynamic Host Configuration Protocol (DHCP) request message sent by a mobile node on a first subnet;

insert data representative of a second subnet into the intercepted DHCP request message to request an Internet Protocol (IP) address associated with the second subnet;

forward the intercepted DHCP request message with the data representative of the second subnet to at least one DHCP server;

intercept a DHCP reply message sent by at least one DHCP server;

select a DHCP reply message has a subnet identifier matching the second subnet; and

forward the selected DHCP reply message to the mobile node.

10. The logic of claim 9, further operable to discard a DHCP reply message that has a subnet identifier that does not match the second subnet.

11. The logic of claim 9, further operable to insert a predetermined subnet selection option having a subnet field into the intercepted message, wherein the predetermined subnet selection option is used to request the server for a network address for a specific subnet;

and

wherein the proxy mobile Internet Protocol entity is further configured to add a subnet mask option request into a parameter request list option of the intercepted message.

12. The logic of claim 11, wherein the subnet field indicates the guest home subnet configured for the mobile node'"'"'s service selection identifier.

13. The logic of claim 11, wherein the subnet field indicates the current home subnet of the mobile node previously assigned to a home subnet.

14. The logic of claim 11, further operable to read identification fields of the intercepted message to find a transaction identifier and a client identifier fields;

and

to store the transaction identifier and the client identifier in an internal table for comparison with respective fields in a received response message.

15. The logic of claim 14, further operable to:

compare the transaction identifier and client identifier fields of the reply message with the respective fields stored in the internal table;

forward the reply message to the mobile node responsive to the transaction identifier and client identifier of the reply message matching the respective fields stored in the internal table; and

discard the reply message responsive to the transaction identifier and client identifier not matching.

16. The logic of claim 9, further operable to assign the mobile node to a local subnet at startup by default.