Method and apparatus for SAS speed adjustment
First Claim
1. A method for maintaining reliable communication on a bidirectional communication link, comprising:
- detecting, by a receiver on the bidirectional communication link, an error;
maintaining, by the receiver, a count of detected errors;
polling the receiver, by a transmitter on the bidirectional communication link, in order to determine the count of detected errors;
performing, by the transmitter, a downshift evaluation for the bidirectional communication link, wherein the downshift evaluation comprises;
requiring transmission speed downshift if the difference between the count of detected errors and a stored count is greater than a predetermined value; and
forgoing transmission speed downshift if the difference between the count of detected errors and the stored count is less than the predetermined value;
in response to performing the downshift evaluation for the path,maintaining a transmission speed of the path if the downshift evaluation determines that forgoing transmission speed downshift is required for the bidirectional communication link; and
reducing the transmission speed of the path if the downshift evaluation determines that transmission speed downshift is required for the bidirectional communication link.
1 Assignment
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Accused Products
Abstract
A method for maintaining reliable communication on a bidirectional communication link is provided. A receiver on the bidirectional communication link detects an error and maintains a count of detected errors. The transmitter on the bidirectional communication link polls the receiver in order to determine the count of detected errors, and performs a downshift evaluation for the bidirectional communication link. In response to performing the downshift evaluation for the bidirectional communication link, the transmitter maintains a transmission speed of the bidirectional communication link if the downshift evaluation determines that forgoing transmission speed downshift is required for the bidirectional communication link, and reduces the transmission speed of the path if the downshift evaluation determines that transmission speed downshift is required for the bidirectional communication link.
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Citations
18 Claims
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1. A method for maintaining reliable communication on a bidirectional communication link, comprising:
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detecting, by a receiver on the bidirectional communication link, an error; maintaining, by the receiver, a count of detected errors; polling the receiver, by a transmitter on the bidirectional communication link, in order to determine the count of detected errors; performing, by the transmitter, a downshift evaluation for the bidirectional communication link, wherein the downshift evaluation comprises; requiring transmission speed downshift if the difference between the count of detected errors and a stored count is greater than a predetermined value; and forgoing transmission speed downshift if the difference between the count of detected errors and the stored count is less than the predetermined value; in response to performing the downshift evaluation for the path, maintaining a transmission speed of the path if the downshift evaluation determines that forgoing transmission speed downshift is required for the bidirectional communication link; and reducing the transmission speed of the path if the downshift evaluation determines that transmission speed downshift is required for the bidirectional communication link. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A system for maintaining reliable communication on a bidirectional communication link, comprising:
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a transmitter; a receiver; and the bidirectional communication link, wherein the bidirectional communication link is coupled to the transmitter and the receiver, wherein the receiver detects an error and maintains a count of detected errors, wherein the transmitter polls the receiver in order to determine the count of detected errors, wherein the transmitter performs a downshift evaluation for the bidirectional communication link, and in response to performing the downshift evaluation, the transmitter maintains the transmission speed of the bidirectional communication link if the downshift evaluation determines that forgoing a transmission speed downshift is required for the bidirectional communication link and the transmitter reduces the transmission speed of the bidirectional communication link if the downshift evaluation determines that a transmission speed downshift is required for the bidirectional communication link, wherein the downshift evaluation comprises wherein the transmitter requires transmission speed downshift if the difference between the count of detected errors and a stored count is greater than a predetermined value and the transmitter forgoes transmission speed downshift if the difference between the count of detected errors and the stored count is less than the predetermined value. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A method for providing reliable point-to-point communications for a bidirectional communication link, comprising:
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determining if a first receiver supports target mode; if the first receiver does not support target mode, then polling a second receiver, by a transmitter, to determine the count of detected errors, wherein the transmitter, the first receiver, and the second receiver are directly coupled to the bidirectional communication link; and if the first receiver supports target mode, then polling at least one of the first receiver and the second receiver, by the transmitter, to determine the count of detected errors; in response to the transmitter polling the count of detected errors in at least one of the first and second receivers, performing, by the transmitter, a downshift evaluation; determining if the downshift evaluation requires a downshift of a transmission speed for the bidirectional communication link, and in response; maintaining the bidirectional communication link transmission speed if the downshift evaluation does not require a reduction in transmission speed; and reducing the bidirectional communication link transmission speed to a next lower path transmission speed if the downshift evaluation requires a reduction in transmission speed, if a lower bidirectional communication link transmission speed is available; and performing, by the transmitter, an up shift evaluation after one of a transmitter power up, a user selection of manual rescan, and the transmitter detects a link-up transition. - View Dependent Claims (17, 18)
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Specification