Item #13, CRC Errors. This statistic is incremented on received packets that pass the Packet Filter mode configured, but contain a Cyclic Redundancy Check error.
Item #14, IEEE 802.3 Length Field Errors. When a received packet contains a Length field value that does not match the actual Protocol Data Unit field length (in accordance with the IEEE 802.3 standard), the firmware increments this statistic.
(Note: Although this statistic normally applies to packets received off the link, it will increment on self"addressed loopback packets containing Length field errors.)
Item #15, More Than One Retry Needed. This counter is incremented whenever more than one retry is required for successful transmission, that is, three or more transmission attempts (the first •retry" is the second attempt).
Item #16, Exactly One Retry Needed. This counter is incremented whenever exactly one retry is needed for successful transmission, that is, two transmission attempts.
Item #17, Transmit Deferrals. When the LAN is in use, the local LANIC card must defer from transmission until the LAN is available. This statistic is the number of packets that experienced at least one deferral prior to transmission. Multiple deferrals of a single packet increments this counter only by one.
Item #18, Transmit Data Underflow Errors. For transmit packets, an error may occur where the Link Controller chip may expect more data than is available. This results in a data underflow to the chip and the counter is incremented.
Item #19, Late Collisions. Normal collisions on transmit result in the LANIC card backing off a random period and retrying transmission. Late collisions are abnormal; they occur subsequent to the period in which a normal collision would be detected (•slot time"). When a late collision occurs during a transmission, a counter is incremented. However, the packet is not retransmitted.
Item #20, Carrier Lost. This statistic reflects the number of packets for which the voltage level of the LAN medium fell below prescribed limits at least one or more times during transmission.
Item #21, Transmit Retry Count Exceeded. A retry limit for transmitting packets may be set at •1" or •15" (two or 16 total transmission attempts, respectively). On repeated collisions, if a packet has not successfully transmitted after the number of retries configured, this statistic is incremented.
Item #22, TDR Information. A Time Domain Reflectometer is a tool for locating discontinuities on the LAN medium by essentially converting the time between a transmitted and reflected pulse to a distance on the medium.
The TDR Information statistic employs the 10 MHz clock on the card to indicate the time (in 100 nanosecond increments) between packet transmission and collision detection. It is provided only when Item #21 (Transmit Retry Count Exceeded) is incremented.
Using Node Manager 5%55