Method for Detecting Topology of Computer Systems

• US 20080310410A1
• Filed: 04/23/2008
• Published: 12/18/2008
• Est. Priority Date: 06/12/2007
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company), Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Original Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Inventors: Mathiasen, Torben
• Granted Patent: US 7,920,560 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/02 Topology update or discovery

Abstract

One embodiment is a method that transmits a packet having a bit field with a Time-to-live (TTL) value from a requesting node to a plurality of receiving nodes. The TTL value is decreased at each of the receiving nodes, and the packet is sent back to the requesting node that compares a value in the bit field with the TTL value to determine a topology of the receiving nodes connected to the requesting node.

Claims

1. ) A method, comprising:

transmitting an Internet Protocol (IP) packet having a bit field with a Time-to-live (TTL) value from a requesting node to a plurality of receiving nodes;

decreasing the TTL value at each of the receiving nodes; and

transmitting the IP packet back to the requesting node that compares a value in the bit field with the TTL value to determine a topology of the receiving nodes connected to the requesting node.

2. ) The method of claim 1 further comprising, subtracting the value in the bit field from the TTL value to determine a number of receiving nodes connected to the requesting node.

3. ) The method of claim 1 further comprising, forwarding the IP packet from a software network bridge in a first receiving node to a software network bridge in a second receiving bridge.

4. ) The method of claim 1 further comprising, modifying a software network bridge in each of the receiving nodes to subtract a value of one from the TTL value when the IP packet is received.

5. ) The method of claim 1 further comprising, subtracting the value in the bit field from the TTL value to determine a hop count that indicates a number of servers connected in a daisy-chain to the requesting node.

6. ) The method of claim 1, wherein the requesting node and receiving nodes are servers located in a computer rack.

7. ) The method of claim 1 further comprising, periodically sending IP packets from each of the receiving nodes to all other nodes to determine the topology of the receiving nodes.

8. ) A tangible computer readable storage medium having instructions for causing a computer to execute a method, comprising:

sending a packet having a bit field with a Time-to-live (TTL) value from a first computer system to a plural computer systems;

modifying with a network bridge in each of the plural computer systems, the TTL value at each of the plural computer systems; and

sending the packet back to the first computer system that evaluates a value in the bit field with the TTL value to determine a topology of the plural computer systems connected to the first computer system.

9. ) The tangible computer readable storage medium of claim 8 further comprising, sending the packet from an upstream port in the first computer system to a downstream port in a second computer system, the first and second computer systems located in a same rack.

10. ) The tangible computer readable storage medium of claim 8 further comprising, decreasing the TTL value by one at each of the plural receiving computer systems.

11. ) The tangible computer readable storage medium of claim 8, wherein the packet is an Internet Protocol (IP) Internet Control Message Protocol (ICMP) echo packet.

12. ) The tangible computer readable storage medium of claim 8 further comprising:

sending the packet from an upstream port of the first computer system to the plural computer systems located above the first computer system;

sending a second packet from a downstream port of the first computer system to other plural computer systems located below the first computer system;

evaluating the packet and second packet at the first computer system to determine a number of servers located in a computer rack.

13. ) The tangible computer readable storage medium of claim 8, wherein the first computer system and the plural computer systems are connected to each other in a daisy-chain configuration in a computer rack.

14. ) The tangible computer readable storage medium of claim 8, wherein the network bridge is software that is modified to decrease the value of the TTL value.

15. ) The tangible computer readable storage medium of claim 8 further comprising, periodically sending echo packets from each of the plural computer systems to each other to determine the topology.

16. ) A computer system, comprising:

a requesting server; and

plural receiving servers coupled to the requesting server;

wherein the requesting server transmits an Internet Protocol (IP) packet having a bit field with a Time-to-live (TTL) value to the plural receiving servers that decrease the TTL value before transmitting the IP packet to another server;

wherein the requesting server compares a value in the bit field with the TTL value to determine a number of the plural receiving servers in the computer system.

17. ) The computer system of claim 16, wherein the IP packet is an echo packet that is transmitted back to the requesting server.

18. ) The computer system of claim 16, wherein the requesting server and plural receiving servers are stacked in a rack.

19. ) The computer system of claim 16, wherein each of the plural receiving servers and the requesting server has a modified software bridge that subtracts a value of one from the bit field.

20. ) The computer system of claim 16, wherein the requesting server and the plural receiving servers are connected in a daisy-chain connection.