Arrangement in a network repeater for monitoring link integrity and selectively down shifting link speed based on local configuration signals

• US 6,728,216 B1
• Filed: 02/24/1999
• Issued: 04/27/2004
• Est. Priority Date: 02/27/1998
• Status: Expired due to Term

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: Advanced Micro Devices, Inc.
• Inventors: Sterner, Rudolph
• Primary Examiner(s): Ton, Dang
• Application Number:
  US09/256,779
• Time in Patent Office: 1,889 Days
• Field of Search: 370/254, 370/252, 370/241, 370/248, 370/251, 370/247, 370/245, 370/246, 370/243, 370/296, 370/279, 370/293, 370/465, 370/466, 370/316, 370/332, 370/333, 370/338, 370/441, 370/342, 370/232, 370/468, 370/401, 370/351, 370/352, 370/249, 370/389, 370/392, 370/402, 370/403, 370/419, 370/423, 370/437, 370/447, 370/458, 370/445, 370/451, 370/462, 370/467, 455/67.1, 455/422, 455/450, 455/452, 455/453, 455/507, 455/517, 455/524, 455/437, 455/522, 710/26, 710/56, 375/224, 375/236
• US Class Current: 370/252
• 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, configuration information supplied by user in circuitry, 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 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 reaches the prescribed threshold, indicating poor link integrity due to poor cable connection or condition, faulty network device, etc., causing 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 monitoring and control by a network manager or other remote management agent. Rather, an interrupt is output from the network repeater to the user circuitry in response to a determined poor link integrity or downshifting operation, enabling the user circuitry to then determine the status of the network repeater.

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, the established link including encoded symbols;

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 and based on a configuration signal supplied to at least one the network repeater, wherein

detecting a number of symbol errors includes

detecting the encoded symbols,

comparing each detected encoded symbol with symbols stored in a symbol definition table,

providing a symbol error indication when any detected encoded symbol does not match one of the symbols stored in the symbol definition table, and

counting each symbol error indication, and

determining the integrity of the link includes

determining whether or not the detected number of symbol error indications occurring in the predetermined number of received encoded symbols equal or exceed a prescribed threshold for a predetermined number of prescribed intervals of receiving said predetermined number of received encoded symbols.

2. The method of claim 1, further comprising generating a signal indicating a problem in the integrity of the link in response to the detected number of symbol error indications reaching the prescribed threshold.

3. The method of claim 2, wherein the signal corresponds to at least one of an LED signal and an interrupt signal.

4. The method of claim 2, wherein the signal is the configuration signal output by user input circuitry to the network repeater.

5. The method of claim 4, further comprising supplying status information to the network repeater indicating at least one of a failed link integrity and a reduction in the data rate based on the failed link integrity.

6. The method of claim 1, wherein the configuration signal enables one of the selectively reducing step, setting the link to the prescribed data rate, and setting the link to the reduced data rate.

7. The method of claim 1, further comprising receiving the prescribed threshold from user input circuitry.

8. The method of claim 1, wherein the selectively reducing step comprises:

breaking the link; and

establishing a second link with the remote network node by auto-negotiation according to the reduced data rate.

9. 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, according to stored configuration information, for establishment of links between the repeater ports and the respective remote network nodes via the respective network media, at least one of the links operating at the first data rate and including encoded symbols;

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

detecting the encoded symbols,

comparing each detected encoded symbol with symbols stored in a symbol definition table,

providing a symbol error indication when any detected encoded symbol does not match one of the symbols stored in the symbol definition table, and

counting the symbol error indications;

a controller having a configuration register for storing the configuration information supplied from a user configuration signal, and configured for selectively changing the at least one link from the first data rate to the second data rate based on the number of symbol error indications reaching a prescribed threshold and according to the stored configuration information, wherein

the symbol error detector includes a counter configured for incrementing a counter value in response to said each symbol error indication, the counter resetting the counter value each prescribed interval of receiving a predetermined number of received encoded symbols; and

the network repeater further comprising;

a user circuit interface for receiving the prescribed threshold and the configuration from a circuit outputting the configuration signal, the controller outputting an interrupt signal in response to the number of symbol error indications, occurring in the predetermined number of received encoded symbols, equaling or exceeding the prescribed threshold for a predetermined number of said prescribed intervals of receiving said predetermined number of received encoded symbols.

10. The network repeater of claim 9, wherein the user circuit interface outputs status information indicating at least one of a failed link integrity and a reduction in the data rate based on the network manager servicing the interrupt signal.