Abstract: Systems and methods provide zone management for devices in a Serial Attached Small Computer System Interface (SAS) topology. In one embodiment, a zone management device stores a zone map that identifies an initial zone of a device in the topology. The management device detects changes in the topology, and identifies a current zone of the device subsequent to the change in the topology. The management device compares the zone map for the device to the current zone to identify a change in the zone of the device, and generates a message for an expander in the topology based on the change in the zone. The management device then transmits the message to the expander to restore the zone of the device to the initial zone.

Abstract: Methods and structure for detecting that arbitration is delaying discovery. One embodiment is a Serial Attached Small Computer System Interface (SAS) expander. The SAS expander includes multiple SAS ports, a port monitor, and a controller. The port monitor is able to track physical link events during arbitration for at least one of the ports while discovery is in progress at the expander, and to detect based on the physical link events that arbitration is delaying discovery. The controller is able to prioritize discovery requests at the expander responsive to detecting that arbitration is delaying discovery.

Abstract: Methods and structure for lane-based multiplexing of physical links are provided. In one embodiment, a Serial Attached Small Computer System Interface (SAS) device is provided. The SAS device comprises a physical link and a controller. The controller is able to time division multiplex the physical link into multiple lanes, and to manage a first connection along one or more of the lanes of the physical link. The controller is further able to detect a request for a second connection, to determine a link rate for the second connection, to select a number of additional lanes at the physical link based on the link rate for the second connection, and to manage the second connection along the additional lanes while the first connection is being managed.

Abstract: A method for managing a request for an outbound connection is provided. The method includes the step of receiving the request for the outbound connection. The request includes a specified connection speed. The method also includes the step of comparing the request for the outbound connection to a plurality of outbound connection options. A further step of the method includes selecting an outbound connection from the plurality of outbound connection options. The selected outbound connection has a connection speed at least equal to the specified connection speed. The selected outbound connection also has the lowest connection speed of the outbound connection options having a connection speed at least equal to the specified connection speed.

Abstract: The disclosure is directed to a system and method for managing connections across a plurality of phys including at least one phy having a first link rate and at least one phy having a second link rate. At least one connection request including a selected link rate is received from an initiator. An arbitration in progress (AIP) delay is provided when at least one phy having the selected link rate or higher is not available. During the AIP delay, a link manager continues to check for a phy having the selected link rate or higher. The link manager completes the connection request if a phy having the selected link rate or higher becomes available before the AIP delay ends.

Abstract: Methods and structure for detecting that arbitration is delaying discovery. One embodiment is a Serial Attached Small Computer System Interface (SAS) expander. The SAS expander includes multiple SAS ports, a port monitor, and a controller. The port monitor is able to track physical link events during arbitration for at least one of the ports while discovery is in progress at the expander, and to detect based on the physical link events that arbitration is delaying discovery. The controller is able to prioritize discovery requests at the expander responsive to detecting that arbitration is delaying discovery.

Abstract: Systems and methods provide zone management for devices in a Serial Attached Small Computer System Interface (SAS) topology. In one embodiment, a zone management device stores a zone map that identifies an initial zone of a device in the topology. The management device detects changes in the topology, and identifies a current zone of the device subsequent to the change in the topology. The management device compares the zone map for the device to the current zone to identify a change in the zone of the device, and generates a message for an expander in the topology based on the change in the zone. The management device then transmits the message to the expander to restore the zone of the device to the initial zone.

Abstract: Systems and methods presented herein provide for the management of link rates for connecting targets devices (e.g., storage devices) to initiators (e.g., host systems). In one embodiment, an expander includes a plurality of PHYs including a PHY having a first link rate and a PHY having a second link rate that is different than the first link rate. The expander also includes a link manager communicatively coupled to the PHYs and operable to process a connection request from an initiator for the first link rate, extract a timer from the connection request, and determine whether the first link rate is available. The link manager is also operable to start the timer when the link manager determines that the first link rate is unavailable and issue a response to the initiator to inform the initiator that the timer has started and that connection at the first link rate is delayed.

Abstract: Systems and methods presented herein provide for managing connections in a SAS domain comprising at least first and second expanders. The first expander detects a failure of the initiator and indicates a change in the SAS domain to the second expander. The second expander detects an increase in arbitration wait time for a connection between the initiator and the target device, determines a race condition exists in the second expander, denies the connection between the initiator and the target device, directs the target device to wait for another connection, performs a discovery of the domain based on the discovery request from the first expander, and prevents a subsequent connection by the target device to the initiator after discovery completes.

Abstract: Systems and methods presented herein provide for managing connections in a SAS domain comprising at least first and second expanders. The first expander detects a failure of the initiator and indicates a change in the SAS domain to the second expander. The second expander detects an increase in arbitration wait time for a connection between the initiator and the target device, determines a race condition exists in the second expander, denies the connection between the initiator and the target device, directs the target device to wait for another connection, performs a discovery of the domain based on the discovery request from the first expander, and prevents a subsequent connection by the target device to the initiator after discovery completes.

Abstract: Methods and structure for lane-based multiplexing of physical links are provided. In one embodiment, a Serial Attached Small Computer System Interface (SAS) device is provided. The SAS device comprises a physical link and a controller. The controller is able to time division multiplex the physical link into multiple lanes, and to manage a first connection along one or more of the lanes of the physical link. The controller is further able to detect a request for a second connection, to determine a link rate for the second connection, to select a number of additional lanes at the physical link based on the link rate for the second connection, and to manage the second connection along the additional lanes while the first connection is being managed.

Abstract: Systems and methods presented herein provide for the management of link rates for connecting targets devices (e.g., storage devices) to initiators (e.g., host systems). In one embodiment, an expander includes a plurality of PHYs including a PHY having a first link rate and a PHY having a second link rate that is different than the first link rate. The expander also includes a link manager communicatively coupled to the PHYs and operable to process a connection request from an initiator for the first link rate, extract a timer from the connection request, and determine whether the first link rate is available. The link manager is also operable to start the timer when the link manager determines that the first link rate is unavailable and issue a response to the initiator to inform the initiator that the timer has started and that connection at the first link rate is delayed.

Abstract: Methods and structure for directly coupling SATA hosts (SATA initiators) with SATA target devices through a SAS fabric and an enhanced SAS expander supporting such direct couplings. The enhanced SAS expander comprises SATA/STP connection logic to open a SAS (STP) connection between a directly attached SATA host and a SATA target device in response to receipt of an FIS from the host or target while no connection is presently open. The opened connection is closed after expiration of a predetermined timeout period of inactivity between the connected host and target. Thus, simpler, less costly SATA hosts and SATA target devices may be utilized while gaining the advantage of SAS architecture flexibility in configuration and scalability. SATA hosts may be coupled through the SAS fabric with a larger number of SATA target devices and multiple SATA hosts may be coupled with the SAS fabric.

Abstract: The disclosure is directed to a system and method for managing connections across a plurality of phys including at least one phy having a first link rate and at least one phy having a second link rate. At least one connection request including a selected link rate is received from an initiator. An arbitration in progress (AIP) delay is provided when at least one phy having the selected link rate or higher is not available. During the AIP delay, a link manager continues to check for a phy having the selected link rate or higher. The link manager completes the connection request if a phy having the selected link rate or higher becomes available before the AIP delay ends.

Abstract: A method for determining a topology based on input/output criteria includes selecting a predefined topology, measuring the fitness of the topology, and breeding individuals from the topology by combining elements from the fittest individuals. The topology is then updated with the new individuals and the fitness of the new topology is measured. Iterations continue similarly until certain criteria are met.

Abstract: A method for managing a request for an outbound connection is provided. The method includes the step of receiving the request for the outbound connection. The request includes a specified connection speed. The method also includes the step of comparing the request for the outbound connection to a plurality of outbound connection options. A further step of the method includes selecting an outbound connection from the plurality of outbound connection options. The selected outbound connection has a connection speed at least equal to the specified connection speed. The selected outbound connection also has the lowest connection speed of the outbound connection options having a connection speed at least equal to the specified connection speed.

Abstract: Methods and structure for directly coupling SATA hosts (SATA initiators) with SATA target devices through a SAS fabric and an enhanced SAS expander supporting such direct couplings. The enhanced SAS expander comprises SATA/STP connection logic to open a SAS (STP) connection between a directly attached SATA host and a SATA target device in response to receipt of an FIS from the host or target while no connection is presently open. The opened connection is closed after expiration of a predetermined timeout period of inactivity between the connected host and target. Thus, simpler, less costly SATA hosts and SATA target devices may be utilized while gaining the advantage of SAS architecture flexibility in configuration and scalability. SATA hosts may be coupled through the SAS fabric with a larger number of SATA target devices and multiple SATA hosts may be coupled with the SAS fabric.