ALR0659E The Class 3 Receive Timeout Frame Rate of port port name in switch switch name was measured to be measured value cnt/s. This violated the defined critical-idle boundary value of boundary value cnt/s.

Explanation

Class 3 Receive Timeout Frame Rate measures the rate at which class 3 frames had to be discarded at the receiving port due to timeout caused by lack of buffer credits at the transmitting port. Buffer to Buffer Credit is used as a mechanism to enforce flow-control by the fibre channel protocol, and ensures that a transmitting port which is sending data does not overrun the ability of the receiving port to receive that data. When out of buffer credits, the port waits for a configurable amount of time (e.g. 500 ms) to receive credit and send the waiting frame. If no credit is received, a timeout condition occurs and the waiting frame is discarded. Note that if egress and ingress ports are on the same blade, the Class 3 Receive Timeout Frame rate increases for the ingress port(s) at the same time the Class 3 Send Timeout Frame rate increases for the egress port.

A threshold was defined on this metric, which causes the measured value to be compared to the defined boundaries for each set of performance statistics collected from the switch. This message indicates that a threshold boundary violation occurred. In this case, the specified port in the switch has a Class 3 Receive Timeout Rate value that is less than or equal to the critical-idle boundary that was defined for the related threshold.