Apparatus and method for isolating and predicting errors in a local area network

• US 4,769,761 A
• Filed: 10/09/1986
• Issued: 09/06/1988
• Est. Priority Date: 10/09/1986
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Smith, Wilson E., Downes, Robert W.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Ramirez, Ellis B.
• Application Number:
  US06/916,913
• Time in Patent Office: 698 Days
• Field of Search: 364/514, 364/552, 364/184, 371/5, 371/3, 371/4, 371/8, 371/11, 371/16
• US Class Current: 709/224
• CPC Class Codes: G06F 11/076 by exceeding a count or rate limit, e.g. word- or bit count limit
• CPC Class Codes: H04L 12/433 with asynchronous transmission, e.g. token ring, register insertion
• CPC Class Codes: H04L 12/437 Ring fault isolation or reconfiguration for SDH/SONET ring networks H04J3/085
• CPC Class Codes: H04L 43/06 Generation of reports
• CPC Class Codes: H04L 43/0823 Errors, e.g. transmission errors
• CPC Class Codes: H04L 43/16 Threshold monitoring

Abstract

Stations of a communications network maintain a set of counters which measure the frequency of occurrence of soft errors in said network. Periodically, each station generates and transmits an error report containing the error counts to a ring error monitor provided in one of the stations. The ring error monitor analyzes the report and calculates and stores weighted error counts for stations in an error domain. The stored error counts are integrated, over a selected time interval, and compared with a threshold value normal for a communications network, operating at acceptable error rate. The results of the comparison set error flags if the limits are exceeded indicating possible future station failures.

Claims

1. In a local area network having a plurality of data terminal equipment (DTE) coupled to a transmission media over which signals are carried for exchanging information between selected DTEs a method for predicting and isolating DTE with excessive rate of errors, comprising the steps of:

(a) at each data terminal equipment, generating and transmitting error report messages, with each message including a first address field with an address for a reporting station, a second address field with an address for a destination station, a third address field with an address for the reporting station nearest active upstream neighbor (NAUN) and an information field carrying error information representative of detected errors;

(b) receiving the message at the destination address;

(c) for like reporting stations, correlating the error information in received error report messages and generating therefrom an error index representing the rate at which error is occurring at a DTE;

(d) periodically adjusting each error index by a selected value;

(e) comparing each resulting error index in step (d) with a threshold value selected from a range of threshold values; and

(f) signaling an error condition for each resulting error index of step (e) falling outside of the threshold value.

2. The method of claim 1 wherein the error index includes weighted error counts.

3. The method of claim 1 wherein the error information includes a plurality of counts with each count corresponding to a different type of error.

4. The method of claim 3 wherein the error index generation of step (c) further includes the steps of:

(g) multiplying the count for each type of error in a received message by values deemed to distribute the error between the reporting station and its NAUN;

(h) summing those products for errors distributed against the reporting station and against its NAUN of step (g) to generate a single weighted error count for the reporting station and a single weighted error count for its NAUN; and

(i) for a currently received error message, adding each of the single weighted error count in step (h) with previously calculated single weighted error counts for like reporting stations and NAUNs.

5. The method set forth in claim 1 further including the step of partitioning the local area network into one or more error domains and transmitting the error report messages from each error domain.

6. The method of claim 5 wherein an error domain includes a reporting station, a NAUN of said reporting station and the transmission media interconnecting said reporting station and its NAUN.

7. A method for predicting and identifying failure in a local area network or like machine before failure occurs comprising the steps of:

(j) monitoring signals from the local area network or like machine;

said signals including a first sequence of electrical indicia representing an address of a reporting station, a second sequence of electrical indicia representing an address for a reporting station NAUN, a third sequence of electrical indicia representing an address for a destination station and a fourth sequence of electrical indicia representing error counts;

(k) analyzing the signals and generating therefrom a table of values representative of weighted error counts detected in said local area network or the like machine;

(l) at a fixed interval, adjusting each value in the table of step (k) by a fixed constant;

(m) comparing each value in step l with a fixed threshold value; and

(n) signaling an error condition for values exceeding the threshold value.

8. The method of claim 7 wherein the interval for adjusting step (l) varies.

9. The method of claim 8 wherein the interval is being varied as a function of the number of entries in the table.

10. The method set forth in claim 9 wherein the threshold value in step (m) is a function of the interval.

11. A device for predicting and identifying failure in a local area network or like machine before failure occurs comprising:

means at stations in the local area network for generating signals including an address for a reporting station, an address for the reporting station NAUN, an address for a destination station and an information field with error counts representative of errors detected in said local area network;

means provided at the destination station for processing the signals and generating therefrom a table of values representative of weighted error counts calculated for stations connected in said local area network or the like machine;

means provided at the destination station for accessing the table of values and adjusting the values therein;

means provided at the destination station for comparing each adjusted value with a threshold value selected from a range of threshold values; and

means provided at the destination station for signaling an error condition for values exceeding the selected threshold value.

12. The device set forth in claim 11 wherein the means for signaling the error condition further includes means for accessing the table of values and setting error flags to identify values which exceed the threshold value.

13. In a local area network having a plurality of DTEs interconnected by a communications media a method for predicting and isolating sections which are having excessive errors, comprising the steps of:

(a) at selected station, generating and transmitting an error report message including an address for a reporting station, an address for a destination station, the address of the reporting station NAUN and an information field containing error counts sorted by error type;

(b) receiving the message at the destination station;

(c) analyzing the message and generating therefrom weighted error counts for each reporting station and its NAUN;

(d) generating a table having a field for addresses of a reporting station, a field for the addresses of the NAUN and a field for weighted error counts;

(e) correlating the weighted error counts with respective reporting station and NAUN and storing in said table indicia representing the address of the reporting station its NAUN and associated weighted error counts calculated in step (c);

(f) thereafter, for each received message calculating weighted error counts for the reporting station and its NAUN contained within said message;

(g) algebraically summing the weighted error counts of step (f) with stored weighted error counts of step (e) only if stations addresses in the table and the message of step (f) are alike;

(h) for stations having matching addresses, replacing the weighted error count in step (e) with the weighted error count in step (g);

(i) periodically adjusting the weighted error count of step (h) with a predetermined number;

(j) comparing each adjusted error count with a range of threshold values; and

(k) signaling an error condition if the adjusted error count in step (j) falls outside of a predetermined range.

14. In a local area network having a plurality of data terminal equipment (DTE) coupled to a transmission media over which signals are carried for exchanging information between selected DTEs a method for predicting and isolating DTE with excessive error rates, comprising the steps of:

(a) at each data terminal equipment, generating and transmitting error report messages, with each message including a first address field with an address for a reporting station, a second address field with an address for a destination station, a third address field with an address for the reporting station nearest active upstream neighbor (NAUN) and an information field carrying error information representative of detected errors;

(b) receiving the message at the destination address;

(c) for like reporting stations, correlating the error information in received error report messages and generating therefrom error indexes representing the rate at which error is occurring at DTEs;

(d) comparing each error index in step (c) with a threshold value selected from a range of threshold values; and

(e) signaling an error condition for each error index of step (d) falling outside of the threshold value.