Method and apparatus for fault location in a loop network

• US 20030056153A1
• Filed: 06/14/2002
• Published: 03/20/2003
• Est. Priority Date: 06/15/2001
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Nicholson, Robert Bruce, Whyte, Barry Douglas, Cashman, Paul Nicholas, Beer, Reginald, Morris, Neil, Maddock, Robert Frank, Judd, Ian David, Hooton, Paul
• Granted Patent: US 6,954,882 B2
• Time in Patent Office: Days
• US Class Current: 714/43
• CPC Class Codes: H04L 12/437 Ring fault isolation or reconfiguration for SDH/SONET ring networks H04J3/085
• CPC Class Codes: H04L 41/0677 Localisation of faults

Abstract

A method and apparatus are provided for fault location in a loop network (100, 200, 400). The network system having a host port (214) for supplying and receiving data and a plurality of successively connected ports (201, 202, 203, 204, 205) through which data from the host port (214) is transferred. A counter (122) for each port records data transfers in which the amount of data received at a destination port is less than an expected amount of data; When a transfer with less than the expected amount of data is identified for a data flow between a sending port (201) and a destination port (214), the counters are incremented for each port (202, 203, 204, 205, 214) after the sending port up to and including the destination port. Analysing means determines a fault location in the network system from the distribution of counts in the counters (122).

Claims

1. A method for fault location in a loop network including a plurality of ports, the method comprising:

identifying a data transfer between two ports in which the data received at a destination port is less then the expected amount of data;

incrementing a count for each port after a sending port for the data transfer up to and including the destination port for each identified data transfer;

analysing the counts to determine a fault location.

2. A method as claimed in claim 1, wherein the step of analysing the counts includes obtaining details of the topology of the loop network.

3. A method as claimed in claim 1, wherein the step of analysing the counts includes ordering the counts in an order according to the number of ports traversed in the loop network.

4. A method as claimed in claim 3, wherein the data transfers are read transfers and the step of analysing the counts identifies a port location in the ordered counts at which the total counts for each port stop incrementing.

5. A method as claimed in claim 3, wherein the data transfers are write transfers and the step of analysing the counts identifies a port location in the ordered counts at which the total counts for each port drops.

6. A method as claimed in claim 1, wherein the data transfers to each port are counted and the step of analysing includes solving simultaneous equations for each port to determine the error rates for each port.

7. A method as claimed in claim 1, wherein the method includes sending and receiving data from a host port to a plurality of successively connected ports.

8. A method as claimed in claim 1, wherein two fault locations are determined in a single analysis by analysing both read and write flows.

9. A method as claimed in claim 1, wherein the loop network is a Fibre Channel Arbitrated Loop.

10. A loop network system comprising:

a host port for supplying and receiving data;

a plurality of successively connected ports through which data from the host port is transferred;

a counter for each port for recording data transfers in which the amount of data received at a destination port is less than an expected amount of data,

wherein, when a data transfer in which the amount of data transferred is less than an expected amount of data is identified for a data transfer between a sending port and a destination port, the counters are incremented for each port after the sending port up to and including the destination port,

analysing means for determining a fault location in the network system from tie distribution of counts in the counters.

11. A loop network system as claimed in claim 10, wherein the analysing means includes means for obtaining details of the topology of the network.

12. A loop network system as claimed in claim 10, wherein the analysing means includes means for ordering the counts for the ports in an order according to the number of ports traversed in the loop network system.

13. A loop network system as claimed in claim 12, wherein the data transfers are read transfers and the analysing means identifies a port location at which the total counts for each port stop incrementing.

14. A loop network system as claimed in claim 12, wherein the data transfers are write transfers and the analysing means identifies a port location at which the total counts for each port drops.

15. A loop network system as claimed in claim 10, wherein the loop network system is a Fibre Channel Arbitrated Troop.

16. A computer program product for fault location in a loop network including a plurality of ports, the computer program product stored on a computer readable storage medium, comprising computer readable program code means for performing the steps of:

identifying a data transfer between two ports in which the data received at a destination port is less then the expected amount of data;

incrementing a count for each port after a sending port for the data transfer up to and including the destination port for each Identified data transfer;

analysing the counts to determine a fault location.