Additional Reference Information

The initial state of a QP's or EEC's APM state machine is Migrated. Using the Modify QP or Modify EEC verbs, software may command the QP or EEC to transition from Migrated to ReArm. Once the two QPs or EECs (currently in the RTS state and with their APM state machines in the ReArm state) have each automatically entered the Arm state upon receipt of a packet with BTH:MigReq = 0, software may use the Modify QP or Modify EEC verb to command a state change from Arm to Migrated. Software cannot command a state change from ReArm to Arm.

Software can only set the state to Migrated when the current state is Armed and the QP or EEC state is RTS. Execution of the Modify QP or Modify EEC verb generates an immediate error if software attempts to set the state to Migrated under any other condition.

Software should load or reload the alternate path information and ensure that the remote QP or EEC has accepted the alternate path information prior to transitioning the state from Migrated to Rearm. Invalid or stale alternate path information doesn't generate any errors when software transitions the state to Rearm. Handling this condition is outside the scope of the specification.

The PMTU for the alternate path must be the same as for the primary path.

The alternate path may use the same or different source and destination ports as those used by the primary path.

After a QP or EEC has transitioned from the Armed to the Migrated state and has switched to using the alternate path, the CA may refuse to accept incoming request or response packets arriving over the original path.