Technique for automatic remote media access control (MAC) layer address resolution

• US 6,292,838 B1
• Filed: 08/23/1999
• Issued: 09/18/2001
• Est. Priority Date: 08/23/1999
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Nelson, William Joseph
• Primary Examiner(s): Burgess, Glenton B.
• Assistant Examiner(s): KUPSTAS, TOD A
• Application Number:
  US09/379,389
• Time in Patent Office: 757 Days
• Field of Search: 709/236, 709/238, 709/242, 709/223, 709/224, 709/245
• US Class Current: 709/236
• 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 61/4523 using lightweight directory access protocol [LDAP]
• CPC Class Codes: H04L 61/4552 Lookup mechanisms between a plurality of directories; Synchronisation of directories, e.g. metadirectories
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]

Abstract

A system and method for determining a MAC layer address of a network interface on a remote device, based on an IP address associated with the same network interface on the remote device. The disclosed system identifies an internetworking device, for example a router, that is attached to the remote subnet to which the network interface of the remote device is attached. The system identifies the network interface of the router that is attached to the remote subnet, and obtains the MAC address of that network interface from an address resolution protocol (ARP) cache associated with it. The system transmits a series of request packets having an IP destination address equal to the provided IP address of the remote device, each including a time to live value, indicating a maximum number of network hops over which each particular packet may be forwarded. The time to live values of the request packets result in each successive request packet being forwarded one hop further along the path to the remote device. The internetworking devices along the route to the remote device each receive one request packet that cannot be forwarded because the time to live value has been decremented to zero. As a result, each internetworking device along the route returns a reply packet to the requesting device indicating its IP address.

Claims

1. A method of determining a point to point address associated with a network interface of a remote device, responsive to an end to end address associated with said network interface of said remote device, comprising:

detecting login information including said end to end address associated with said network interface of said remote device, wherein said remote device is a remote end station, and wherein said login information further includes information identifying a user of said remote end station;

extracting, responsive to said detecting of said login information, said end to end address associated with said network interface of said remote device from said login information;

identifying, responsive to said end to end address, an internetworking device communicably coupled to a remote network to which said network interface is also communicably coupled;

identifying, responsive to said end to end address, an interface of said internetworking device which is attached to said remote network; and

obtaining, responsive to said end to end network address, said point to point address of said network interface from a database of point to point addresses of network interfaces of devices that are communicably coupled to said remote network, wherein said database is associated with said interface of said internetworking device attached to said remote network.

2. The method of claim 1, wherein said point to point address is a data link layer address.

3. The method of claim 1, wherein said point to point address is a media access control (MAC) layer address.

4. The method of claim 1, wherein said to end address is a network layer address.

5. The method claim 1, wherein said end to end address is a internet protocol (IP) layer address.

6. The method of claim 1, wherein said step of identifying an internetworking device communicably coupled to said remote network to which said network interface is also communicably coupled further comprises:

transmitting a plurality of request packets, each of said request packets including a network layer destination address equal to said end to end address, each one of said request packets further including a corresponding maximum hop count value indicating a maximum number of hops said one of said plurality of request packets may be transmitted over;

receiving respective ones of said plurality of request packets at each of at least one internetworking device located along a route to said remote network;

determining, at each of said at least one internetworking device located along said route to said remote network, responsive to said maximum hop count value indicating said maximum number of hops said respective one of said plurality of request packets may be transmitted over, that said respective one of said plurality of request packets cannot be forwarded;

transmitting, at each one of said at least one internetworking device located along said route to said remote network, responsive to said determining that said respective one of said plurality of request packets cannot be forwarded, a response packet including an end to end address of said one of said at least one internetworking device along said route to said remote network; and

identifying said internetworking device communicably coupled to said remote network to which said network interface is also communicably coupled, responsive to receipt of said response packet from each one of said at least one internetworking device located along said route to said remote network.

7. The method of claim 6, wherein said request packets comprise Internet Control Message Protocol (ICMP) echo request packets.

8. The method of claim 7, wherein said reply packets comprise ICMP echo reply packets.

9. The method of claim 6, wherein said plurality of request packets comprise UDP probe packets.

10. The method of claim 9, wherein said rely packets comprise ICMP port unreachable packets.

11. The method of claim 6, wherein said transmitting said plurality of request packets further comprises generating an incremented maximum hop count value for each successive one of said plurality of request packets.

12. The method of claim 6, further comprising:

receiving a respective one of said plurality of request packets at said network interface of said remote device;

determining, at said remote device, responsive to said maximum hop count value, that said respective one of said plurality of request packets cannot be forwarded;

transmitting, at said remote device, responsive to said determining that said respective one of said plurality of request packets cannot be forwarded, a response packet including said end to end address of said network interface of said remote device; and

wherein said identifying said internetworking device communicably coupled to said remote network to which said network interface is also communicably coupled, is further responsive to receipt of said response packet from said remote device.

13. The method of claim 1 wherein said identifying said interface of said internetworking device further comprises:

determining an address of said remote network; and

using said address of said remote network to determine said interface of said internetworking device.

14. The method of claim 13, wherein said determining said address of said remote network includes performing a logical AND operation with said end to end address of said remote device and a subnet mask of said remote network.

15. The method of claim 1, wherein said remote network is a subnet.

16. The method of claim 1, wherein said step of obtaining said point to point address of said network interface from said database of point to point addresses of network interfaces of devices that are communicably coupled to said remote network comprises accessing an address resolution protocol cache.

17. The method of claim 16, wherein said step of obtaining said point to point address of said network interface from said database of point to point addresses of network interface of devices that are communicably coupled to said remote network comprises issuing a simple network management protocol (SNMP) get request command.

18. A computer program product including a computer readable medium, said computer readable medium having a computer program for determining a point to point address associated with a network interface of a remote device responsive to an end address associated with said network interface of said remote device stored thereon, said computer program comprising:

program code for detecting login information including said end to end address associated with said network interface of said remote device, wherein said remote device is a remote end station, and wherein said login information further includes information identifying a user of said remote end station;

program code for extracting, responsive to said detecting of said login information, said end to end address associated with said network interface of said remote device from said login information;

program code for identifying, responsive to said end to end address, an internetworking device communicably coupled to a remote network to which said network interface is also communicably coupled;

program code for identifying, responsive to said end to end address, an interface of said internetworking device which is attached to said remote network; and

program code for obtaining, responsive to said end to end network address, said point to point address of said network interface from a database of point to point addresses of network interfaces of devices that are communicably coupled to said remote network, wherein said database is associated with said interface of said internetworking device attached to said remote network.

19. A computer data signal embodied in a carrier wave, said computer data signal including a computer program for determining a point to point address associated with a network interface of a remote device responsive to an end address associated with said network interface of said remote device, said computer program comprising:

program code for detecting login information including said end to end address associated with said network interface of said remote device, wherein said remote device is a remote end station, and wherein said login information further includes information identifying a user of said remote end station;

program code for extracting, responsive to said detecting of said login information, said end to end address associated with said network interface of said remote device from said login information;

program code for identifying, responsive to said end to end address, an internetworking device communicably coupled to a remote network to which said network interface is also communicably coupled;

program code for identifying, responsive to said end to end address, an interface of said internetworking device which is attached to said remote network; and

program code for obtaining, responsive to said end to end network address, said point to point address of said network interface from a database of point to point addresses of network interfaces of devices that are communicably coupled to said remote network, wherein said database is associated with said interface of said internetworking device attached to said remote network.