Arrangement in a network repeater for monitoring link integrity by monitoring symbol errors across multiple detection intervals

• US 6,690,650 B1
• Filed: 02/24/1999
• Issued: 02/10/2004
• Est. Priority Date: 02/27/1998
• Status: Expired due to Term

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: Advanced Micro Devices, Inc.
• Inventors: Stener, Rudolph
• Primary Examiner(s): Ton, Dang
• Application Number:
  US09/256,780
• Time in Patent Office: 1,812 Days
• Field of Search: 370/254, 370/252, 370/241, 370/248, 370/251, 370/247, 370/245, 370/246, 370/243, 370/296, 370/297, 370/293, 370/279, 370/465, 370/466, 370/310, 370/333, 370/332, 370/338, 370/441, 370/342, 370/232, 370/468, 455/67.1, 455/421, 455/450, 455/452, 455/453, 455/507, 455/517, 455/524, 375/130, 375/134, 375/140, 375/225, 375/226, 375/227, 375/367, 375/240, 375/211, 375/213, 375/284, 375/285, 714/710, 714/751, 714/752, 714/754
• US Class Current: 370/241
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0021 in which the algorithm uses adaptive thresholds
• CPC Class Codes: H04L 25/20 Repeater circuits; Relay circuits
• CPC Class Codes: H04L 43/0847 Transmission error
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 5/1446 of transmission speed
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A network repeater having a plurality of repeater ports selectively establishes links with remote nodes at one of two data rates based on the capabilities of the remote network node and a determined link integrity. A network repeater establishes a link with a network node using auto-negotiation techniques to establish a 100 Mb/s link. The network repeater than monitors the link for symbol errors, and determines an integrity of the link based on a detected number of symbol errors relative to a prescribed threshold in a dual-counter configuration. If the detected number of symbol errors counted by the first counter reaches a first threshold within a first number of received symbols, the second counter is incremented and the first counter reset. If over a second, longer interval the second counter reaches a second threshold, indicating repeated symbol errors over a greater distribution of received symbols, the network repeater performs a down shifting operation by breaking the established 100 Mb/s link, and restarting auto-negotiation to establish a 10 Mb/s link. Hence, the network repeater may monitor high-speed links for link integrity, and selectively downshift a link encountering a substantial number of errors to a reduced data rate, without a necessity of a network manager or other remote management agent.

Claims

1. A method in a network repeater, comprising:

establishing a link with a remote network node at a prescribed data rate via a network medium; and

determining an integrity of the link by;

(1) counting in a first counter a detected number of symbol errors within a first interval,

(2) incrementing a second counter if the detected number of symbol errors exceeds a first threshold within the first interval, and

(3) determining if the second counter reaches a second threshold within a second interval including a successive plurality of the first intervals, the link integrity based on the second counter reaching the second threshold within the second interval.

2. The method of claim 1, wherein the first interval corresponds to a first prescribed number of symbols received from the remote network node.

3. The method of claim 2, wherein the second interval corresponds to a second prescribed number of received symbols substantially larger than the first prescribed number of received symbols.

4. The method of claim 3, wherein the counting step includes resetting the first counter upon reaching the first prescribed number of received symbols.

5. The method of claim 4, wherein the incrementing step includes resetting the second counter if the first counter does not reach the first threshold upon reaching the first prescribed number of received symbols.

6. The method of claim 4, further comprising resetting the second counter upon reaching the second prescribed number of received symbols.

7. The method of claim 1, wherein the first threshold corresponds to a selected significant bit of the detected number of symbol errors, the incrementing step including detecting a transition in the selected significant bit of the detected number of symbol errors.

8. The method of claim 1, wherein the second threshold corresponds to a selected significant bit of the value of the second counter, the incrementing step including detecting a transition in the selected significant bit of the value of the second counter.

9. The method of claim 1, further comprising supplying at least one of the first and second thresholds to the network repeater via a serial interface.

10. The method of claim 1, further comprising generating a signal indicating a problem in the integrity of the link in response to the second counter reaching the second threshold.

11. The method of claim 1, further comprising selectively reducing the data rate on the network medium from the prescribed data rate to a reduced data rate in response to the second counter reaching the second threshold within the second interval.

12. The method of claim 1, wherein the first and second thresholds represent a first symbol error rate and a second symbol error rate, respectively, the second symbol error rate being substantially less than the first symbol error rate.

13. A network repeater having a plurality of repeater ports configured for sending and receiving data packets between remote network nodes via respective network media, the network repeater comprising:

a first repeater core configured for sending and receiving data packets between a first group of the repeater ports according to a first data rate;

a second repeater core configured for sending and receiving data packets between a second group of the repeater ports according to a second data rate slower than the first data rate;

an auto-negotiation unit configured for selecting one of the first and second data rates for establishment of links between the repeater ports and the respective remote network nodes via the respective network media;

a symbol error detector for detecting a number of symbol errors on at least one of the links operating at the first data rate, the symbol error detector comprising;

(1) a first counter for counting a detected number of symbol errors within a first interval, and

(2) a second counter for counting, within a second interval larger than the first interval, a number of the first intervals having the detected number of symbol errors exceeding a first prescribed threshold; and

a controller for detecting an integrity of the at least one link based on the counter value of the second counter reaching a second threshold within the second interval.

14. The repeater of claim 13, wherein the controller selectively changes the at least one link from the first data rate to the second data rate based on the value of the second counter reaching the second threshold within the second interval.

15. The network repeater of claim 13, wherein the first and second thresholds corresponding to selected significant bits of the first and second counter values, respectively, the second counter being incremented based on a transition in the selected significant bit of the first counter value.

16. The network of claim 13, wherein the first and second intervals correspond to first and second numbers of received symbols, respectively, wherein the first counter is reset at the end of each first interval and the second counter is reset at the end of each second interval.