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

Appendix A 211
LINKCONTROL Command
NS 3000/iX 100Base-T Link Statistics
frames. The maximum printable value of this 64-bit field is 17 digits, or
about 99 million billion frames. In the previous example, 127700 frames
were transmitted at normal priority.
Transmits no error — Total number of frames the adapter card
reports it successfully transmitted onto the medium. These adapter
card statistics are periodically read, and are accumulated by the link
driver. The total includes all unicast, broadcast, and multicast frames
that were successfully transmitted on the first attempt, as well as
frames that were successfully transmitted after being deferred or that
experienced one or more collisions. It should equal the value of
“Transmits”. The maximum printable value of this 64-bit field is 17
digits, or about 99 million billion frames. In the previous example,
127700 frames were transmitted.
Transmits dropped — Total number of frames the link driver
discarded because the transmit queue was full, or because the data to
be sent was fragmented beyond recognition. The maximum value of this
32-bit field is 2147483647. It would be unusual for this statistic to
contain a nonzero value.
NOTE Collisions occur on 100Base-T Local Area Network links whenever two
nodes on the link attempt to transmit data at the same time. When a
collision occurs, each node involved in the collision waits a random
amount of time, called random backoff, before attempting to again
transmit the frame along the link. Many of the fields described in this
section are incremented whenever a collision occurs.
Transmits deferred — Total number of frames that were deferred to
other network traffic before their initial transmission onto the network.
This means that the 100Base-T card had to wait for carrier to drop and
stay dropped for a few nanoseconds, before attempting to transmit the
frame. The maximum printable value of this 64-bit field is 17 digits, or
about 99 million billion frames. In the previous example, 1738 transmit
frames were deferred.
Transmits 1 retry — This field indicates the number of frames that
collided once before being transmitted successfully. This means that the
random backoff strategy was only used once. The maximum printable
value of this 64-bit field is 17 digits, or about 99 million billion frames.
In the example above, 86 frames were transmitted after only one
collision. This statistic is not logged when the adapter card is operating
in full duplex mode, and would print as 0.
Transmits >1 retry — This field indicates the number of frames that
collided more than once, but fewer than 16 times, before being
transmitted successfully onto the link. If the frame was not transmitted
successfully (more than 16 attempts were made without success), then
the card aborts transmission of this frame, and it counts the event in
the “Trans 16 collisions” field. The maximum printable value of this
64-bit field is 17 digits, or about 99 million billion frames. In the