IP network for accomodating mobile users with incompatible network addressing

• US 6,434,627 B1
• Filed: 03/15/1999
• Issued: 08/13/2002
• Est. Priority Date: 03/15/1999
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Ng, Chi-Shing, Millet, Mark E.
• Primary Examiner(s): Barot, Bharat
• Application Number:
  US09/268,559
• Time in Patent Office: 1,247 Days
• Field of Search: 703/201-203, 703/217-218, 703/223, 703/227, 703/238-239, 703/245, 703/246, 703/249, 703/250, 713/200-202, 713/152-153, 713/160-161, 370/253, 370/351-356, 370/392-393, 370/401
• US Class Current: 709/245
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/10 of different types
• CPC Class Codes: H04L 61/25 of the same type
• 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]
• CPC Class Codes: H04W 88/16 Gateway arrangements

Abstract

An flexible address translation method allows a computer network to automatically learn that a visiting node has attached and then automatically establish a virtual gateway so that the visiting node can communicate through the network with local nodes, other visiting nodes, and/or Internet sites. The network performs an address translation to enable the connectivity of the visiting node. The network maintains one or more globally unique outside addresses that point to it. In other words, packets addressed to the one or more outside addresses are routed to the network. When a visiting node connects to the network, the network translates the source address of packets from the node to a particular one of its outside addresses. The network also replaces destination addresses in packets received by the network that are addressed to the particular outside address. Specifically, the network replaces the globally unique outside address with the “home” address of the visiting node. Thereafter, the packet is forwarded to the visiting node, which is now connected to the network.

Claims

1. A method of providing network connections for visiting nodes at a remote network, the visiting nodes being configured to connect through a home network that is remote from the remote network, the method comprising:

establishing a virtual gateway on the remote network for a visiting node by responding to a message from the visiting node addressed to a default gateway on the home network of the visiting node, which virtual gateway behaves as the home default gateway for the visiting node; and

in a packet received at the virtual gateway, switching a home IP address of the visiting node with a globally unique outside address provided by the remote network.

2. The method of claim 1, wherein establishing the virtual gateway comprises sending a default gateway packet to the visiting node, the default gateway packet indicating that the remote network can handle Internet traffic from the visiting node.

3. The method of claim 2, wherein the default gateway packet identifies a gateway node on the remote network that is configured to act as virtual gateway.

4. The method of claim 2, wherein the default gateway packet is a reply to a default gateway ARP packet sent by the visiting node.

5. The method of claim 1, wherein switching the home IP address with a globally unique outside address takes place when the packet is sent from the visiting node, and wherein the source IP address of such packets is replaced with the globally unique outside address.

6. The method of claim 5, further comprising forwarding the packet to a destination on the Internet.

7. The method of claim 1, wherein switching the home IP address with a globally unique outside address takes place when the packet has the globally unique outside address as a destination IP address, and wherein the destination IP address of the packet is replaced with the home IP address of the visiting node.

8. The method of claim 1, further comprising creating a translation entry specifying the home IP address of the visiting node and the globally unique outside address.

9. The method of claim 8, wherein the address translation entry specifies a destination IP address for node on the Internet with which the visiting node communicates.

10. The method of claim 1, further comprising checking a list of translation entries to identify the home IP address of the visiting node and the globally unique outside address.

11. The method of claim 1, further comprising determining that the visiting node has made a Domain Name System request addressed to a home name server that is not on the remote network.

12. The method of claim 11, further comprising redirecting the Domain Name Service request to a remote name server to which the remote network is configured to submit Domain Name Service requests.

13. An apparatus configured to provide network connections for visiting nodes at a remote network, the visiting nodes being configured to connect through a home network that is remote from the remote network, the apparatus comprising:

one or more processors;

a memory in communication with at least one of the processors;

an address translation list including one or more translation entries, each specifying a home IP address of the visiting node and a globally unique outside address,

wherein the globally unique outside address is provided by the remote network and the home IP address is the IP address of the visiting node on its home network, and

wherein at least one of the processors and the memory is configured or designed to act as a virtual gateway on the remote network for a visiting node, which virtual gateway behaves as the home default gateway for the visiting node by responding to a message from the visiting node addressed to a default gateway on the home network of the visiting node.

14. The apparatus of claim 13, wherein the virtual gateway sends a default gateway packet to the visiting node, which default gateway packet indicating that the remote network can handle Internet traffic from the visiting node.

15. The apparatus of claim 14, wherein the default gateway packet identifies a gateway node on the remote network that is configured to act as virtual gateway.

16. The apparatus of claim 14, wherein the default gateway packet is a reply to a default gateway ARP packet sent by the visiting node.

17. The apparatus of claim 13, wherein an address translation entry specifies a destination IP address for node on the Internet with which the visiting node communicates.

18. The apparatus of claim 13, wherein at least one of the processor is configured or designed to determine the visiting node has made a Domain Name System request addressed to a home name server that is not on the remote network;

and then redirect the Domain Name Service request to a remote name server to which the remote network is configured to submit Domain Name Service requests.

19. The apparatus of claim 13, wherein the apparatus is a network device.

20. The apparatus of claim 13, wherein the apparatus is a router.

21. The apparatus of claim 13, further comprising an operating system that configures the apparatus to act as the virtual gateway.

22. The apparatus of claim 13, further comprising an operating system that configures the apparatus to perform address translation by switching the globally unique outside address and the home IP address on packets to and from the visiting node.

23. A computer program product comprising:

(a) a machine readable medium; and

(b) program instructions contained in the machine readable medium, the program instructions specifying a method for providing network connections for visiting nodes at a remote network, the visiting nodes being configured to connect through a home network that is remote from the remote network, the method comprising;

establishing a virtual gateway on the remote network for a visiting node by responding to a message from the visiting node addressed to a default gateway on the home network of the visiting node, which virtual gateway behaves as the home default gateway for the visiting node; and

in a packet received at the virtual gateway, switching a home IP address of the visiting node with a globally unique outside address provided by the remote network.

24. The computer program product of claim 23, wherein establishing the virtual gateway comprises sending a default gateway packet to the visiting node, the default gateway packet indicating that the remote network can handle Internet traffic from the visiting node, and wherein the default gateway packet is a reply to a default gateway ARP packet sent by the visiting node.

25. The computer program product of claim 23, wherein switching the home IP address with a globally unique outside address takes place when the packet is sent from the visiting node, and wherein the source IP address of such packets is replaced with the globally unique outside address.

26. The computer program product of claim 23, wherein switching the home IP address with a globally unique outside address takes place when the packet has the globally unique outside address as a destination IP address, and wherein the destination IP address of the packet is replaced with the home IP address of the visiting node.

27. The computer program product of claim 23, further comprising program instructions for creating a translation entry specifying the home IP address of the visiting node and the globally unique outside address.

28. The computer program product of claim 23, further comprising program instructions for checking a list of translation entries to identify the home IP address of the visiting node and the globally unique outside address.

29. The computer program product of claim 23, further comprising program instructions for determining that the visiting node has made a Domain Name System request addressed to a home name server that is not on the remote network;

and redirecting the Domain Name Service request to a remote name server to which the remote network is configured to submit Domain Name Service requests.