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 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: 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 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.