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

212 AppendixA
LINKCONTROL Command
NS 3000/iX 100Base-T Link Statistics
previous example, 179 frames were transmitted after experiencing
between 2 and 15 collisions. This statistic is not logged when the
adapter card is operating in full duplex mode, and would print as 0.
Trans 16 collisions — This field indicates the number of times a
frame was not transmitted, because 16 consecutive collisions occurred.
This can occur during periods of high network utilization. If the node is
experiencing many Trans 16 errors, possible causes include the
following:
• The network is saturated with traffic.
• There is a short in the cable.
• There is an opening in the cable.
The maximum value of this 32-bit field is 2147483647. This statistic is
not logged when the adapter card is operating in full duplex mode, and
would print as 0.
Trans late collision — This field indicates that a frame was active in
the network for a longer time than is permitted by the protocol. No
attempt is made to retransmit a frame after a late collision. The
IEEE 802.3 protocol expects each frame to be transmitted within one
slot time (the expected time for a 512 bit frame to traverse the entire
network). The slot time exceeds the amount of time a single frame
should need to traverse the entire network.
A value in this field indicates that a network problem caused a late
collision. A late collision is one in which the collision occurs after one
slot time has passed and another node, sensing that the network is
inactive, begins to transmit a frame. Late collisions are caused by one of
the following:
• A network that is too long.
• Broken 100Base-T cards in the network.
A network can be made too long by installing too many repeaters
between nodes. The 100Base-T card hardware detects collisions after
the 512 bit timer expires even though IEEE 802.3 standards do not
require the link to be monitored beyond that time. The maximum value
of this 32-bit field is 2147483647. This statistic is not logged when the
adapter card is operating in full duplex mode, and would print as 0.
Trans underruns — Total number of frames aborted by the adapter
card during transmission because the remaining data was not made
available to the transmit hardware fast enough. It indicates unexpected
latency on the dedicated internal bus onboard the adapter card. If this
condition occurs, the adapter will automatically adjust to improve the
latency, and retransmit the aborted frame automatically. The maximum
value of this 32-bit field is 2147483647. For this statistic, a value of less
than 3 would be considered normal.