Method and apparatus for automatic network address assignment

• US 20070266125A1
• Filed: 07/18/2007
• Published: 11/15/2007
• Est. Priority Date: 04/19/1999
• Status: Active Grant

• Current Assignee: Gang Lu, James O'Toole, M Kaashoek
• Original Assignee: Gang Lu, James O'Toole, M Kaashoek
• Inventors: O'Toole, James, Lu, Gang, Kaashoek, M.
• Granted Patent: US 7,899,889 B2
• Time in Patent Office: Days
• US Class Current: 709/222
• CPC Class Codes: H04L 2101/604 Address structures or formats
• CPC Class Codes: H04L 2101/668 Internet protocol [IP] address subnets
• CPC Class Codes: H04L 41/0806 for initial configuration or provisioning, e.g. plug-and-play
• CPC Class Codes: H04L 41/0853 by actively collecting configuration information or by backing up configuration information
• CPC Class Codes: H04L 61/103 across network layers, e.g. resolution of network layer into physical layer addresses or address resolution protocol [ARP]
• CPC Class Codes: H04L 61/5092 by self-assignment, e.g. picking addresses at random and testing if they are already in use

Abstract

In one embodiment, a subnet mask is automatically determined by a first network node attached to a subnet in a packet communication network. The first network node issues plural communication packets from plural source addresses to at least one address known to be used in the subnet to evoke responses, and based on the presence or absence of responses from the network nodes at the known addresses, the first network node determines the subnet mask which represents the subnet.

Claims

1. A method for automatically determining a subnet mask by a first network node attached to a subnet in a packet communication network, the method comprising the steps of:

issuing plural communication packets from plural source addresses to at least one address known to be used in the subnet to evoke responses; and

based on the presence or absence of responses from the network nodes at the known addresses, determining the subnet mask which represents the subnet.

2. The method according to claim 1 further including the step of identifying plural source addresses just inside and outside a possible subnet mask.

3. The method according to claim 2 wherein plural source addresses are randomly selected.

4. The method according to claim 2 further including the step of forwarding a message to a known address on the subnet, from the source addresses.

5. The method according to claim 4 wherein the message is an ICMP request.

6. The method according to claim 4 wherein the step of determining is based on whether a response is received from the known address.

7. The method according to claim 2 wherein the step of determining includes determining whether a node having the same address as the source address has been observed issuing other subnet communications.

8. The method according to claim 1 wherein the steps of issuing and determining are repeated until a response is received from just within a possible subnet mask and not from just outside the possible subnet mask.

9. The method according to claim 1 wherein the steps of issuing and determining are repeated until exhausting possible subnet masks.

10. The method according to claim 9 wherein an appropriate search method is applied to exhaust possible subnet masks.

11. The method according to claim 10 wherein the search method is a binary search.

12. A network node attached to a subnet capable of automatically determining a subnet mask in a packet communication network, comprising:

an interface coupled to a subnet including at least one other network node; and

a processor operating a processor routine, the processor being coupled to the interface to;

issue plural communication packets from plural source addresses to at least one address known to be used in the subnet to evoke responses; and

based on the presence or absence of responses from the network node at the known address, determine the subnet mask which represents the subnet.

13. The network node according to claim 12 wherein the processor further identifies plural source addresses just inside and outside a possible subnet mask.

14. The network node according to claim 13 wherein the processor further forwards a message to a known address on the subnet, from the source addresses.

15. The network node according to claim 12 wherein the processor repeats the issuing and determining steps until a response is received from just within a possible subnet mask and not from just outside the possible subnet mask.

16. The network node according to claim 15 wherein repeating the issuing and determining steps is performed in a binary search manner.

17. An apparatus in a network node coupled to a network having one or more network nodes, the apparatus comprising:

a storage means that stores a processor routine for determining a network configuration; and

a processor loading the processor routine;

the processor being commanded by the processor routine to;

issue plural communication packets from plural source addresses to at least one address known to be used in the subnet to evoke responses; and

based on the presence or absence of responses from the network node at the known address, determine the subnet mask which represents the subnet.

18. The apparatus according to claim 17 wherein the processor routine further identifies a source address at the edge of the possible subnet masks.

19. The apparatus according to claim 18, wherein the processor routine further forwards a message to a known address on the subnet, from the source address.

20. The apparatus according to claim 17, wherein the processor routine repeats the issuing and determining subnet masks based on the responses from other network nodes until a response is received from just within a possible subnet mask and not from just outside the possible subnet mask.

21. The apparatus according to claim 20 wherein repeating the issuing and determining steps is performed in a binary search manner.

22. A processing device attached to a subnet in a packet communication network for determining a subnet mask, the processing device comprising:

means for providing possible subnet masks;

means for issuing at least one communication packet to the subnets defined by the respective subnet masks;

means for collecting responses from other network nodes on the subnet; and

means for determining whether one of the subnet masks represents the subnet.

23. The processing device of claim 22 wherein the means for issuing, collecting, and determining continue to work until a response is received from just within a possible subnet mask and not from just outside the possible subnet mask