Arrangement in a network repeater for monitoring link integrity and automatically down shifting link speed

• US 8,184,677 B1
• Filed: 02/24/1999
• Issued: 05/22/2012
• Est. Priority Date: 02/27/1998
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: GlobalFoundries, Inc.
• Inventors: McRobert, Stephen, Sterner, Rudolph
• Primary Examiner(s): Bocure, Tesfaldet
• Application Number:
  US09/256,786
• Time in Patent Office: 4,836 Days
• Field of Search: 375/211, 375/213, 375/219, 375/220, 375/224, 375/225, 375/295, 375/316, 375/377, 375/222, 370/241, 370/242, 370/246, 370/247, 379/1.01, 379/4, 455/7, 455/14
• US Class Current: 375/213
• 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 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 then 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. If the detected number of symbol errors reaches the prescribed threshold, indicating poor link integrity due to poor cable connection or condition, faulty network device, etc., 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 function.

Claims

1. A method in a network repeater of controlling transmissions, the method comprising:

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

monitoring the link by counting a detected number of symbol errors and decrementing a counter in response to detecting one of the symbol errors; and

determining an integrity of the link based on the detected number of symbol errors relative to a prescribed threshold.

2. The method of claim 1, wherein the decrementing step includes halting the decrementing of the counter if the counter has a value of zero.

3. The method of claim 1, wherein the determining step includes determining the integrity relative to a prescribed time interval equal to about one millisecond, the time interval being controlled by a timer counting down to zero.

4. A method in a network repeater of controlling transmissions, the method comprising:

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

monitoring the link by counting a detected number of symbol errors;

determining an integrity of the link based on the detected number of symbol errors relative to a prescribed threshold; and

selecting the prescribed threshold from a plurality of thresholds.

5. A method in a network repeater of controlling transmissions, the method comprising:

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

monitoring the link by counting a detected number of symbol errors;

determining an integrity of the link based on the detected number of symbol errors relative to a prescribed threshold; and

supplying the prescribed threshold to the network repeater via a serial interface.

6. A method in a network repeater of controlling transmissions, the method comprising:

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

monitoring the link by counting a detected number of symbol errors;

determining an integrity of the link based on the detected number of symbol errors relative to a prescribed threshold; and

selectively reducing the data rate on the network medium to a reduced data rate in response to the detected number of symbol errors exceeding the prescribed threshold.

7. The method of claim 6, wherein the monitoring step includes decrementing an error counter in response to detection of each of said symbol errors, the method further comprising resetting the error counter to the threshold in response to the timer reaching zero, after resetting the value of the counter.

8. The method of claim 6, wherein the selectively reducing step includes reducing the data rate in response to the detected number of symbol errors exceeding the prescribed threshold and based on an enable signal.

9. A method in a network repeater of controlling transmissions, the method comprising:

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

monitoring the link by counting a detected number of symbol errors; and

determining an integrity of the link based on the detected number of symbol errors relative to a prescribed threshold,

wherein the determining step includes;

decrementing a timer from a prescribed time interval;

decrementing a first counter initially set at a first threshold in response to a detected symbol error; and

determining, in response to the timer reaching zero, whether the first counter has a zero value, the integrity determined based on the first counter having the zero value coincident with the timer reaching zero.

10. 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;

to negotiation unit respective network media;

a symbol error detector for detecting a number of symbol errors relative to a prescribed time interval on at least one of the links operating at the first data rate; and

a controller for selectively changing the at least one link from the first data rate to the second data rate based on the number of symbol errors reaching a prescribed threshold.

11. The repeater of claim 10, wherein the symbol error detector includes a counter configured for decrementing a counter value in response to each of the detected symbol errors.

12. The repeater of claim 11, further comprising an optional interface to a network management agent for receiving the prescribed threshold from a network manager, the controller outputting a notification signal to the network manager in response to the number of symbol errors reaching the prescribed threshold.