NS3000/iX Operations and Maintenance Reference Manual (36922-90042)

216 AppendixA
LINKCONTROL Command
NS 3000/iX 100Base-T Link Statistics
based on address: about 63 percent of all frames received are then being
dropped. This level would be considered high.
Recv dropped: buffer — Total number of frames received from the
adapter card, but dropped because no data buffers were available from
the upper layer protocol requesting to receive these frames. This is a
relatively common occurrence, amounting to flow control for all
protocols sharing those buffers. Many protocols include built-in
mechanisms for detecting lost frames and requesting their
retransmission from the remote side. The maximum value of this 32-bit
field is 2147483647. In the previous example, out of 66.4 million frames
received, 262 have been dropped for lack of buffer resources; any
similar level would be considered normal.
Recv dropped: dma — The link driver design now queues frames
under conditions of low DMA resources, so this statistic is now obsolete,
should never contain a nonzero value, and may be deleted in a future
release. This statistic is not applicable to PCI and is not displayed for
PCI 100Base-T links.
Recv dropped descr — Total number of times the adapter card
reported it was unable to receive a frame because of a problem with the
receive instructions specified by the software driver. The maximum
value of this 32-bit field is 2147483647. It would be unusual for this
statistic to contain a nonzero value. This statistic is only applicable for
PCI 100Base-T links.
Recv dropped: other — Sum total number of frames received from
the adapter card, but dropped because: an upper layer protocol error
was returned; the required address format was not supported; the
frame arrived while the link driver was in an unusual state; or for
perfect multicast filtering reasons. The maximum value of this 32-bit
sum is 2147483647. In the previous example, 24785 frames have been
dropped for one or more of the reasons listed; this number would be
considered high, and further investigation might be needed if it appears
to be impacting any applications.
Recv deferred — Number of times an address-matched receive frame
was temporarily held (queued) by the link driver, because of a
momentary lack of DMA resources. Once those resources became
available, the frame was automatically transferred to the host. The
maximum printable value of this 64-bit field is 17 digits, or about 99
million billion frames. In the previous example, 123 frames were
temporarily held. This statistic is not applicable to PCI and is not
displayed for PCI 100Base-T links.
Recv overruns — Total number of address-matched frames that could
not be received into the adapter card, either because prior data was not
being removed by the receive hardware fast enough, or because their
size exceeded the maximum frame size. May indicate unexpected
latency on the dedicated internal bus onboard the adapter card, which
cannot be automatically adjusted by the link driver. The maximum