System and method using packet filters for wireless network communication

• US 6,657,981 B1
• Filed: 03/06/2000
• Issued: 12/02/2003
• Est. Priority Date: 01/17/2000
• Status: Expired due to Fees

• Current Assignee: Accton Technology Corporation
• Original Assignee: Accton Technology Corporation
• Inventors: Lee, Hong-Yuh, Chang, Ruei-chuan, Huang, Liang-yi, Chiang, Mei-Ling
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Fox, Jamal A.
• Application Number:
  US09/519,087
• Time in Patent Office: 1,366 Days
• Field of Search: 370/338, 370/401, 455/432, 455/552, 709/238, 709/245, 709/321, 709/324, 709/327
• US Class Current: 370/331
• CPC Class Codes: H04L 61/10 of different types
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection
• CPC Class Codes: H04W 36/0019 adapted for mobile IP [MIP]
• 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 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A network communication system is provided for communicating a wired subnet and a wireless subnet to solve the handover problems occurred in roaming. The system includes an IAPP manager program at a user level of the access point for communicating with a kernel-level device driver using system calls to perform an announce procedure and a handover procedure. A wireless LAN card driver with a packet filter is implemented for sending signals to the IAPP manager program to perform the handover procedure upon receiving a reassociation request packet from a mobile host. A wired LAN card driver is implemented for acting as an interface of the wired subnet. And a bridge program with a packet filter is implemented to increase the bandwidth efficiency.

Claims

1. A network communication system on an access point for communicating a wired subnet and a wireless subnet, comprising:

an IAPP manager program at a user level of said access point for communicating with a kernel-level device driver by system calls to perform an announce procedure and a handover procedure, and maintain a mapping table, said mapping table comprising a physical address and an IP address of each associated access point;

a wireless LAN card driver at a kernel level of said access point for sending signals to said IAPP manager program to perform said handover procedure upon receiving a reassociation request packet from a mobile host, said wireless LAN card driver comprising a first packet filter for determining if an incoming packet is to be forwarded to said wireless subnet according to a registration record of said mobile host;

a wired LAN card driver at said kernel level of said access point acting as an interface of said wired subnet; and

a bridge program for interfacing between said wired LAN card driver and said wireless LAN card driver, said bridge program having a second packet filter for determining if said incoming packet is to be forwarded to said wireless subnet according to a registration record of said mobile host.

2. The network communication system as claimed in claim 1, wherein said IAPP manager program comprises:

means for getting the information of an access point.

3. The network communication system as claimed in claim 1, wherein said IAPP manager program comprises:

means for getting a physical address of a mobile host and a physical address of an access point previously registered by said mobile host.

4. The network communication system as claimed in claim 1, wherein said IAPP manager program comprises:

means for storing each process ID of said IAPP manager program in said wireless LAN card driver.

5. The network communication system as claimed in claim 1, wherein said IAPP manager program comprises:

means for deleting from said first packet filter a physical address of a mobile host after said mobile host has roamed away.

6. The network communication system as claimed in claim 1, wherein said mapping table records an IP address and a physical address of an access point read from each incoming announce response packet in response to an announce request.

7. The network communication system as claimed in claim 1, wherein said IAPP manager program uses UDP/IP for data transmission.

8. A method of wireless network communication for communicating a wired subnet and a wireless subnet on an access point, said access point having a wireless LAN card driver with a first packet filter, a wired LAN card driver implemented at its kernel level, and a bridge program with a second packet filter, comprising the steps of:

providing an IAPP manager program for using system calls to get a physical address of said wireless LAN card driver when said access point is initially activated, said physical address acting as a BSSID of an announce request packet which is broadcast simultaneously to a current subnet of said access point and associated subnets;

reading, in response to an incoming announce response packet, the physical address and the IP address of said incoming announce response packet, and building a mapping table for storing said physical address and said IP address of an access point read from said incoming announce response packet;

signaling said IAPP manager program by said wireless LAN card driver in response to a reassociation request packet to get the physical address of previously registered access point read from said reassociation request packet, and lookup an;

associated IP address from said mapping table, and said associated IP address acting as a destination address for a handover request packet, and simultaneously insert the physical address of mobile host read from said reassociation request packet to said first packet filter;

calling said wireless LAN card driver by system calls in response to a handover request packet, and said wireless LAN card driver simultaneously deleting the registration record indicated by the hardware address of said handover request packet from said first packet filter;

determining, in response to an incoming packet with a Mobile IP header, if said incoming packet is broadcast by Mobile IP Agent;

when determining said incoming packet is broadcast by Mobile IP Agent, and no registration procedure is undergoing on the access point for a mobile host, rejecting to forward said incoming packet.

9. The method as claimed in claim 8, further comprising the step of:

forwarding said incoming packet to said wireless subnet when determining that said incoming packet is broadcast by a Mobile IP Agent and a registration procedure is undergoing on the access point for a mobile host.

10. The method as claimed in claim 8, wherein;

said announce request packet comprises;

Station Service Identification number (SSID), Basic Service Set (BSS), physical communication type, and channel number.

11. The method as claimed in claim 8, wherein said announce response packet comprises:

Station Service Identification number (SSID), Basic Service Set(BSS), physical communication type, announce cycle time, Beacon cycle time, Handover Timeout, and channel number.

12. The method as claimed in claim 8, wherein said handover request packets and said handover response packets comprise:

Station Service Identification number (SSID), Basic Service Set(BSS), Basic Service Set Identification number (BSSID), a physical address of a mobile host, and message Identification number.