This counter contains the number of frames that were either not transmitted or re-transmitted due to a Tx DMA under-run. If the device is configured to retransmit on under-run, this counter may be updated multiple times for a single frame. Under-runs occur because a lack of PCI bandwidth resulted in the device's internal transmit FIFO running dry during the transmission of a frame. The adaptive algorithms within the software keep this number under control. To see how the adaptive algorithm is doing, refer to the "Current Threshold" section.

•Tx Defer Count

This counter indicates transmit defer events. A defer event occurs when the transmitter cannot immediately send a packet due to the medium being busy, either because another device is transmitting or the link is not up.

•Tx with No CRS

This counter counts the number of successful packet transmissions in which the Carrier Sense input from the PHY was not asserted within one slot time of start of transmission. The PHY should assert Carrier Sense during every transmission. Failure to do so may indicate that the link has failed, or the PHY has an incorrect link configuration. This counter is not valid in TBI mode, and is only valid when the device is operating at full-duplex.

•Rx Sequence Error Count

This counter indicates receive sequence error events. This counter increments along with the Rx Symbol Error Count when either the fiber cable is disconnected or the connector is not seated completely.

•Rx Length Error Count

This counter indicates receive length error events. A length error occurs if an incoming packet is undersized (less than 64 bytes) or oversized (greater than 1522).

•Rx DMA Too Early

This counter counts the total number of times that the device attempted to perform an Early DMA operation (by speculatively requesting the host bus prior to reception of the entire packet) and ran out of data to DMA before the device was forced to relinquish ownership of the bus. This condition is really not an "error" condition, but is nevertheless counted for diagnostic purposes. This statistic is valid only if Early Receives are enabled.

•XON Received Count

This counter indicates the number of XON packets received. XON packets can occur when Flow Control is enabled and both the adapter and its link partner are configured to use it.

•XON Transmitted Count

This counter indicates the number of XON packets transmitted. XON packets can occur when Flow Control is enabled and both the adapter and its link partner are configured to use it.

•XOFF Received Count

This counter indicates the number of XOFF packets received. XOFF packets can occur when Flow Control is enabled and both the adapter and its link partner are configured to use it.

•XOFF Transmitted Count

This counter indicates the number of XOFF packets transmitted. XOFF packets can occur when Flow Control is enabled and both the adapter and its link partner are configured to use it.

•Flow Control Received Unsupported Count

Installation 40