WLAN device and method for numbering frames with sequence numbers

• US 7,636,342 B2
• Filed: 03/04/2006
• Issued: 12/22/2009
• Est. Priority Date: 08/19/2005
• Status: Expired due to Fees

• Current Assignee: Hon Hai Precision Industry Co., Ltd.
• Original Assignee: Hon Hai Precision Industry Co., Ltd.
• Inventors: Tang, Cheng-Wen
• Primary Examiner(s): Hsu; Alpus H
• Assistant Examiner(s): COSTIN, JEREMY M
• Application Number:
  US11/308,051
• Publication Number:
  US 20070189245A1
• Time in Patent Office: 1,389 Days
• Field of Search: 370389-3951, 370/338, 370/349, 709223-224
• US Class Current: 370/338
• CPC Class Codes: H04L 2101/622 Layer-2 addresses, e.g. medium access control [MAC] addresses
• CPC Class Codes: H04L 61/35 involving non-standard use of addresses for implementing network functionalities, e.g. coding subscription information within the address or functional addressing, i.e. assigning an address to a function
• CPC Class Codes: H04L 63/1458 Denial of Service
• CPC Class Codes: H04L 63/1466 Active attacks involving interception, injection, modification, spoofing of data unit addresses, e.g. hijacking, packet injection or TCP sequence number attacks
• CPC Class Codes: H04W 12/122 Counter-measures against attacks; Protection against rogue devices
• CPC Class Codes: H04W 12/125 Protection against power exhaustion attacks
• CPC Class Codes: H04W 12/126 Anti-theft arrangements, e.g. protection against subscriber identity module [SIM] cloning
• CPC Class Codes: H04W 80/02 Data link layer protocols

Abstract

A method for numbering a plurality of frames with sequence numbers is implemented in a wireless network device having a plurality of data units, and includes the steps of: providing receiver addresses of the data units; and numbering each data unit with a respective sequence number according to the receiver address of the data unit. A WLAN device employing the method is also disclosed for avoiding denial of service (DoS) attacks and man-in-the-middle attacks.

Claims

1. A wireless local area network (WLAN) device for transmitting data units, comprising:

a media access control (MAC) layer protocol module for numbering data units with sequence numbers, wherein the data units comprise MAC management protocol data units (MMPDUs) and MAC service data units (MSDUs), each data unit comprises a receiver address, and the MAC layer protocol module comprises;

a numbering module for numbering each data unit with a respective sequence number according to the receiver address of the data unit, the numbering module comprising;

a counting list module comprising a plurality of counting modules for numbering each data unit with a sequence number; and

a selection module for selecting a first counting module for numbering the data unit with a sequence number according to the receiver address of the data unit if the data unit is an MMPDU, and a second counting module for numbering the data unit with a sequence number according to the receiver address of the data unit if the data unit is an MSDU;

wherein the first counting module numbers the MMPDU with a sequence number according to a first mathematical function, the second counting module numbers the MSDU with a sequence number according to a second mathematical, and the first mathematical function is different from the second mathematical function.

2. The WLAN device as claimed in claim 1, wherein the numbering module further comprises a first determining module for determining whether the data unit is an MMPDU.

3. The WLAN device as claimed in claim 2, wherein the numbering module further comprises a second determining module for determining whether the sequence number numbered by the applicable counting module is less than a predetermined threshold value.

4. The WLAN device as claimed in claim 3, wherein the numbering module further comprises a setting module for setting a sequence number to the data unit according to the results of the determinations of the first determining module and the second determining module.

5. The WLAN device as claimed in claim 1, wherein the MAC layer protocol module further comprises an MAC processing module for generating a plurality of data units, applying sequence numbers to the data units, and adding related information fields to the data units to form MAC protocol data units (MPDUs).

6. The WLAN device as claimed in claim 5, further comprising a physical layer protocol module for generating physical protocol data units (PPDUs) by encapsulating the MPDUs into the PPDUs.

7. The WLAN device as claimed in claim 6, further comprising a high-level protocol module for providing a plurality of data units to the MAC layer protocol module.

8. The WLAN device as claimed in claim 7, further comprising a data interface for receiving the data units from the high-level protocol module, and transmitting the data units to the numbering module.

9. The WLAN device as claimed in claim 7, further comprising a data interface for receiving the data units from the high-level protocol module, and transmitting the data units to the MAC processing module.

10. A method for numbering a plurality of frames with sequence numbers, implemented in a wireless network device having a plurality of data units, the method comprising the steps of:

providing receiver addresses of the data units, wherein the data units comprise media access control service data units (MSDUs) and media access control management protocol data units (MMPDUs); and

numbering each data unit with a respective sequence number according to the receiver address of the data unit, the numbering step comprising;

selecting a first counting module for numbering the data unit with a sequence number according to the receiver address of the data unit if the data unit is an MMPDU, and a second counting module for numbering the data unit with a sequence number according to the receiver address of the data unit if the data unit is an MSDU;

wherein the first counting module numbers the MMPDU with a sequence number according to a first mathematical function, the second counting module numbers the MSDU with a sequence number according to a second mathematical, and the first mathematical function is different from the second mathematical function.

11. The method as claimed in claim 10, wherein the numbering step further comprises:

determining whether the data unit is an MMPDU;

numbering the MMPDU with a sequence number by the first counting module, if the data unit is an MMPDU;

determining whether the sequence number numbered by the first counting module is less than a predetermined threshold value; and

setting the sequence number numbered by the first counting module to the MMPDU, if the sequence number is less than the predetermined threshold value.

12. The method as claimed in claim 11, further comprising the step of setting a predetermined sequence number to the MMPDU, if the sequence number numbered by the first counting module is not less than the predetermined threshold value.

13. The method as claimed in claim 11, further comprising the steps of:

numbering the data unit with a sequence number by the second counting module, if the data unit is not an MMPDU but an MSDU;

determining whether the sequence number numbered by the second counting module is less than the predetermined threshold value; and

setting the sequence number numbered by the second counting module to the MSDU, if the sequence number is less than the predetermined threshold value.

14. The method as claimed in claim 13, further comprising the step of setting a predetermined sequence number to the MSDU, if the sequence number numbered by the second counting module is not less than the predetermined threshold value.

15. The method as claimed in claim 13, further comprising the step of applying the set sequence number of each data unit to the data unit.