Address resolution for internet protocol sub-networks in asymmetric wireless networks

• US 6,618,398 B1
• Filed: 06/08/1999
• Issued: 09/09/2003
• Est. Priority Date: 08/06/1998
• Status: Expired due to Fees

• Current Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Boray, Giridhar K., Pillai, Krishnakumar, Weeresinghe, Ranjith, Marchetti, Fabio Marco, Jahani, Farshideh Ghazi, Abu-Amara, Hosame
• Primary Examiner(s): Nguyen, Lee
• Assistant Examiner(s): TRAN, TUAN A
• Application Number:
  US09/337,210
• Time in Patent Office: 1,554 Days
• Field of Search: 370/465, 370/466, 370/467, 370/469, 370/479, 370/475, 370/401, 370/328, 455/12.1, 455/428
• US Class Current: 370/475
• CPC Class Codes: H04B 7/18582 Arrangements for data linking, i.e. for data framing, for error recovery, for multiple access
• 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: H04W 4/18 Information format or content conversion, e.g. adaptation by the network of the transmitted or received information for the purpose of wireless delivery to users or terminals
• 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 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185

Abstract

A method for address resolution in a wireless system, with an originating Satellite Interface Terminal (SIT) and a destination Satellite Interface Terminal (SIT2). An Address Resolution Protocol (ARP) packet of a source is modified when transmitted to a destination and when returned from the destination to the source. The modification involves substituting the SIT1 address for that of the source in the ARP request packet and substituting the SIT2 address for that of the destination in the ARP reply packet, respectively.

Claims

1. A method for address resolution in a wireless system, with an originating interface terminal and a destination interface terminal, said method comprising:

replacing at said originating interface terminal a source address within an Address Resolution Protocol (ARP) request packet issued from a source device with an address of said origination air interface terminal to Winch said packet is issued wherein said origination air interface terminal operates as a gateway for at least one connected source device, including said source device having said source address different from the address of said origination air interface terminal, and wherein said replacing step generates a modified ARP request packet and includes (i) replacing an Ethernet MAC address of said source device with a MAC address of said originating air interface terminal in an ARP Protocol Data Unit (PDU) and (ii) replacing said Ethernet MAC address of said source device with the MAC address of said originating air interface terminal in a source field of an Internet Protocol (IP) datagram of said source device;

transmitting said modified ARP request packet to a destination air interface terminal via an air interface, said destination air interface terminal operating as a gateway for at least one destination device having a destination address different from an address of said destination air interface terminal;

responsive to a receipt of a modified ARP reply packet transmitted via said air interface from said destination air interface terminal;

substituting an address of said origination air interface terminal within said reply packet with that of said source device; and

forwarding said ARP reply packet to said source device using the source address.

2. The method of claim 1, wherein said originating air interface terminal and said destination air interface terminal are satellite interface terminals that are both capable of supporting multiple source/destination devices having different addresses, and said transmitting step includes:

transmitting said modified ARP request packet via a satellite air interface and receiving said modified ARP reply packet via said satellite air interface; and

when it is determined at the destination satellite interface terminal (STI2) that a received packet is said modified ARP request packet, replying to said modified ARP request packet with a modified ARP reply packet in which a destination address is replaced with an address of said destination satellite interface terminal.

3. The method of claim 2, wherein said replying step further includes the steps of:

analyzing said modified ARP request packet received at said destination to determine if it has been modified; and

replacing a source address field of said ARP reply packet and a target Ethernet MAC address of said ARP PDU with a MAC address of said destination satellite interface terminal when an ARP request packet received at said destination has been modified.

4. The method of claim 3, wherein said replacing step is completed at said destination satellite interface terminal.

5. The method of claim 3, wherein said replying step further comprises the steps of:

analyzing said destination MAC address field in said ARP reply packet to determine an appropriate PID value corresponding to said originating satellite interface terminal; and

encapsulating said ARP reply packet within an MPEG stream utilizing said appropriate PID value and MPEG-2 encoding.

6. The method of claim 2, wherein:

said substituting step further comprises;

substituting a MAC address of said originating satellite interface terminal in said ARP reply packet with a MAC address of said source, said substituting being competed at said originating satellite interface terminal; and

said forwarding step comprises transmitting said ARP reply packet containing address resolution information from said originating satellite interface terminal to said source.

7. The method of claim 1, said replacing step comprising substituting a media access control (MAC) address of said source device in said transmitted ARP request packet with a MAC address of said originating interface terminal to generate said modified ARP request packet.

8. The method of claim 1, wherein said transmitting step includes the steps of:

analyzing a destination MAC address field of said modified ARP request packet to determine if intended for broadcast; and

encapsulating said modified ARP request packet when said ARP is intended for broadcast.

9. The method of claim 8, said encapsulating step includes the steps of:

assigning a Program Identifier (PID) value to said modified ARP utilizing MPEG-2 encoding; and

encapsulating said IP packet within an MPEG stream generated by said MPEG-2 encoding.

10. The method of claim 8, wherein said analyzing and encapsulating steps are completed within a Forward Link Subsystem (FLSS).

11. A system for address resolution in a wireless system having an originating interface terminal and a destination interface terminal, said system comprising:

means for replacing at said originating air interface terminal a source address within an Address Resolution Protocol (ARP) request packet issued from a source device with an address of said origination air interface terminal to which said packet is issued, wherein said origination air interface terminal operates as a gateway for at least one connected source device, including said source device having said source address different from the address of said origination air interface terminal, and wherein said replacing step generates a modified ARP request packet and includes (i) means for replacing an Ethernet MAC address of said source device with a MAC address of said originating air interface terminal in an ARP Protocol Data Unit (PDU) and (ii) means for replacing the Ethernet MAC address of said source device with a MAC address of said originating air interface terminal in a source field of an Internet Protocol (IP) datagram of said source device;

means for transmitting said modified ARP request packet to a destination air interface terminal via an air interface, said destination air interface terminal operating as a gateway for at least one destination device having a destination address different from an address of said destination air interface terminal; and

means responsive to a receipt of a modified ARP reply packet transmitted via said air interface from said destination air interface terminal, for;

substituting an address of said origination air interface terminal within said reply packet with that of said source device; and

forwarding said ARP reply packet to said source device using the source address.

12. The system of claim 11, wherein said originating air interface terminal and said destination air interface terminal are satellite interface terminals that are both capable of supporting multiple source/destination devices having different addresses, and said transmitting means includes:

means for transmitting said modified ARP request packet via a satellite air interface and receiving said modified ARP reply packet via said satellite air interface; and

means, when it is determined at the destination satellite interface terminal (SIT2) that a received packet is said modified ARP request packet, for replying to said modified ARP request packet with a modified ARP reply packet in which a destination address is replaced with an address of said destination satellite interface terminal.

13. The system of claim 12, wherein said replying means further includes:

means for analyzing said modified ARP request packet received at said destination to determine if it has been modified; and

means for replacing a source address field of said ARP reply packet and a target Ethernet MAC address of said ARP PDU with a MAC address of said destination satellite interface terminal when an ARP request packet received at said destination has been modified.

14. The system of claim 13, wherein said replacing means is associated with said destination interface terminal.

15. The system of claim 13, wherein said replying means further comprises:

means for analyzing said destination MAC address field in said ARP reply packet to determine an appropriate PID value corresponding to said originating satellite interface terminal; and

means for encapsulating said ARP reply packet within an MPEG stream utilizing said appropriate PID value and MPEG-2 encoding.

16. The system of claim 15, wherein;

said substituting means further comprises means for substituting a MAC address of said originating satellite interface terminal in said ARP reply packet with a MAC address of said source, said substituting being competed at said originating satellite interface terminal; and

said forwarding means comprises means for transmitting said ARP reply packet containing address resolution information from said originating satellite interface terminal to said source.

17. The system of claim 11, said replacing means comprising substituting a Media Access Control (MAC) address of said source device in said transmitted ARP request packet with a MAC address of said originating interface terminal to generate said modified ARP request packet.

18. The system of claim 11, wherein said transmitting means includes:

means for analyzing a destination MAC address field of said modified ARP request packet to determine if intended for broadcast; and

means for encapsulating said modified ARP request packet when said ARP is intended for broadcast.

19. The system of claim 18, said encapsulating means includes:

means for assigning a Program Identifier (PID) value to said modified ARP utilizing MPEG-2 encoding; and

means for encapsulating said IP packet within an MPEG stream generated by said MPEG-2 encoding.

20. The system of claim 18, wherein said analyzing and encapsulating means are included within a Forward Link Subsystem (FLSS).

21. A system for address resolution in a wireless system, with an originating Satellite Interface Terminal (SIT1) and a destination Satellite Interface Terminal (SIT2), said system comprising:

means for masking a medium access control MAC address of far end Internet protocol devices with a MAC address of an associated satellite interface terminal to which said devices are connected, said means for masking including; and

means for replacing at said associated satellite air interface terminal a first address within an Address Resolution Protocol (ARP) request packet issued from a device with an address of said associated satellite air interface terminal to which said packet is issued, wherein said associated satellite air interface terminal operates as a gateway for at least one connected device, including said device having said first address different from the address of said associated satellite air interface terminal, and said replacing step generates a modified ARP request packet and includes (i) means for replacing an Ethernet MAC address of said device with a MAC address of the associated satellite interface terminal in an ARP Protocol Data Unit (PDU) and (ii) means for replacing the Ethernet MAC address of said device with a MAC address of the associated satellite interface terminal in a source field of an Internet Protocol (P) datagram of said device;

means for providing said MAC address of said satellite interface terminal to a source device of a forward link subsystem via an air interface operating according to Unicast functionality.

22. The system of claim 21, said means for masking further comprising:

means for transmitting said modified ARP request packet to a destination air interface terminal via an air interface, said destination air interface terminal operating as a gateway for at least one destination device having a destination address different from an address of said destination air interface terminal,

means responsive to a receipt of a modified ARP reply packet transmitted via said air interface from said destination air interface terminal, for;

substituting an address of said origination air interface terminal within said reply packet with that of said source device; and

forwarding said ARP reply packet to said source device using the source address; and

means responsive to a receipt of a modified ARP request packet transmitted via said air interface from said destination air interface terminal, for;

generating an ARP reply packet; and

replacing a source address field of said ARP reply packet and an target Ethernet MAC address of said ARP PDU with a MAC address of said destination satellite interface terminal when an ARP request packet received has been modified.