Network address management for a wired network supporting wireless communication to a plurality of mobile users

• US 5,159,592 A
• Filed: 10/29/1990
• Issued: 10/27/1992
• Est. Priority Date: 10/29/1990
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Perkins, Charles E.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): HSU, ALPUS
• Application Number:
  US07/605,592
• Time in Patent Office: 729 Days
• Field of Search: 370/60, 370/85.1, 370/85.2, 370/85.3, 370/85.7, 370/85.13, 370/94.1, 370/94.3, 370/95.1, 340/825.5, 340/825.51, 455/39, 455/68, 455/53.1, 455/54.1, 455/54.2, 455/55.1, 455/56.1
• US Class Current: 370/338
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 61/5007 Internet protocol [IP] addresses
• CPC Class Codes: H04L 61/5061 Pools of addresses
• 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 8/26 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 80/06 Transport layer protocols, e.g. TCP [Transport Control Protocol] over wireless transmission control protocol/Internet protocol [TCP/IP] or user datagram protocol [UDP] H04L69/16
• CPC Class Codes: H04W 92/02 Inter-networking arrangements
• CPC Class Codes: Y10S 370/91 Carrier sense multiple access, e.g. ethernet, 10base-t

Abstract

Apparatus and method for managing bidirectional transmission of information between a wired network and at least one mobile communication unit (10) in wireless communication with the wired network. The wired network is of the type wherein users of the network are each assigned a unique network address such as in, for example, a TCP/IP network. In accordance with the invention there is provided a local gateway (16) coupled between a wireless LAN and the wired network for communication with a mobile communication unit. There is also provided a global gateway (18) coupled to the local gateway and to remote users of the network. The global gateway functions to maintain a plurality of network addresses and, in response to a request for an assignment of a network address from the mobile communication unit, assigns one of the plurality of network addresses to the requesting mobile communication unit. The global gateway also buffers and routes data received from a remote user, the data being directed to an addresss corresponding to the assigned network address, to the mobile communication unit having the assigned address.

Claims

1. A method for transmitting information in a network that includes a wireless network and a wired network, the network having at least one mobile communication unit in wireless communication with the wired network over the wireless network, the network being characterized in that users of the network are each assigned a unique network address, comprising the steps of:

establishing, through the wireless network, communication between the wired network and a mobile communication unit;

requesting an assignment of a network address for the mobile communication unit, the request being made to a network gateway by the mobile communication unit through the wireless network, the network gateway being bidirectionally coupled to the wired network for providing communications to remote users of the network;

in response to the request, assigning, with the network gateway, a network address to the mobile communication unit, the assigned address being transmitted from the network gateway to the wired network;

receiving the assigned network address with the mobile communication unit, the assigned address being received through the wireless network; and

in response to the received network address, the mobile communication unit thereafter communicating with the network by employing the assigned network address.

2. A method as set forth in claim 1 wherein the steps of establishing, requesting, transmitting, and receiving each include a step of routing information between the wireless network and the wired network through a local gateway, the local gateway being coupled between the wireless network and, through the wired network, to the network gateway.

3. A method as set forth in claim 2, wherein, in response to the mobile communication unit becoming uncoupled from the wireless network, the method further includes the steps of:

notifying the network gateway that the mobile communication unit is no longer active, the step of notifying including a step of sending a message from the local gateway over the wired network to the network gateway; and

in response to the notification by the local gateway, deassigning, at the network gateway, the assigned network address.

4. A method as set forth in claim 3 wherein the step of notifying includes an initial step of buffering within the local gateway, for a predetermined interval of time, any information received from the wired network that is addressed to the mobile communication unit that is no longer active, and wherein, if the mobile communication unit again becomes coupled to the wireless network before the expiration of the predetermined interval of time, the local gateway does not execute the step of notifying.

5. A method as set forth in claim 1 and further including a step of buffering, at the network gateway, packets of data addressed to the assigned network address during a time that the mobile communication unit is not actively coupled to the wireless network.

6. A method as set forth in claim 5 wherein in response to the mobile communication unit indicating that it is once more actively coupled to the wireless network, further including the steps of:

retrieving the buffered packets of data;

forwarding the retrieved packets to a local gateway that is bidirectionally coupled between the wired network and the wireless network; and

transmitting the retrieved packets from the local gateway to the mobile communication unit over the wireless network.

7. A method as set forth in claim 1 wherein the step of assigning includes a step of allocating the assigned network address from a pool of network addresses that is maintained by the network gateway.

8. A method as set forth in claim 7 wherein the wired network conforms to a Transmission Control Protocol/Internet Protocol standard and wherein the step of allocating includes an initial step of reserving a plurality of Internet Protocol addresses for use by the network gateway.

9. A method as set forth in claim 1 wherein the step of requesting includes a step of transmitting, from the mobile communication unit to the network gateway, an identifier that is unique to the mobile communication unit.

10. A method as set forth in claim 9 wherein the step of assigning assigns a single network address to a plurality of mobile communication units, the assigned network address including, for each of the plurality of mobile communication units, the respective one of the unique identifiers so as to differentiate the plurality of mobile communication units one from another.

11. A method as set forth in claim 1 and, in response to a message from the mobile communication unit that the mobile communication unit intends to terminate communication with the wired network, the method includes a further step of deassigning the assigned network address at the network gateway.

12. A method as set forth in claim 1 and, in response to a name inquiry to determine a network address that is associated with a name, further including the steps of:

if the name is associated with a permanently assigned network address, returning the permanently assigned network address in response to the inquiry;

if the name is associated with a temporarily assigned network address, returning the temporarily assigned network address in response to the inquiry; and

if the name is associated with a previously assigned network address, returning a predetermined network address that differs from the previously assigned network address.

13. In a data communications network comprised of a wired network and a wireless network, apparatus for managing the bidirectional transmission of information between the wired network and at least one mobile communication unit in wireless communications with the wired network over the wireless network, the data communications network being characterized in that users of the data communications network are each assigned a unique network address, comprising:

local gateway means, coupled between a wireless Local Area Network (LAN) and the wired network, for communicating with a mobile communication unit; and

global gateway means coupled to the local gateway means and to remote users of the data communications network, the global gateway means including means for maintaining a plurality of network addresses, means for receiving a request for an assignment of a network address from the mobile communication unit, means for assigning one of the plurality of network addresses to the requesting mobile communication unit; and

means for routing data received from a remote user, the data having an address corresponding to the assigned network address, to the mobile communication unit having the assigned address.

14. Apparatus as set forth in claim 13 wherein the global gateway means further includes means for buffering data received from a remote user, the received data being addressed to a mobile communication unit having one of the assigned network addresses.

15. Apparatus as set forth in claim 13 wherein the data communications network includes a plurality of wireless LANs each of which has at least one local gateway means coupled thereto.

16. Apparatus as set forth in claim 15 and further comprising a plurality of global gateway means individual ones of which are coupled to different ones of the plurality of wireless LANs through at least one of said local gateway means, each of said plurality of global gateway means including means for assigning network addresses to mobile communication units in wireless communication with their respective wireless LANs.

17. Apparatus as set forth in claim 13 wherein the network addresses correspond to Internet Protocol address.

18. Apparatus as set forth in claim 13 wherein the local gateway means includes means for buffering data addressed to one or more mobile communication units that are coupled to the wireless LAN.

19. In a data communications network comprised of a wired network and a wireless network, a method for managing the bidirectional transmission of information between the wired network and at least one mobile communication unit in wireless communication with the wired network over the wireless network, the data communications network being characterized in that users of the data communications network are each assigned a unique network address, comprising the steps of:

maintaining a plurality of the unique network addresses with a global gateway means, the global gateway means being bidirectionally coupled to a local gateway means, through the wired network, and also to remote users of the data communications network, the local gateway means being coupled between the wireless and the wired network;

receiving, at the global gateway means, a request for an assignment of the network address from a mobile communication unit;

in response to the received request, assigning one of the plurality of network addresses to the requesting mobile communication unit; and

in response to a message received from a remote user, the message having an address that corresponds to the assigned network address, routing the message from the global gateway to the local gateway means, and from the local gateway means to the wireless network for reception by the mobile communications unit having the assigned network address.

20. A method as set forth in claim 19 wherein the wired network operates in accordance with a protocol known as a Transmission Control Protocol, wherein the step of maintaining maintains network addresses that correspond to a protocol known as an Internet Protocol, and wherein the wireless network operates in accordance with a protocol other than the Transmission Control Protocol.