When an SDLC or token ring connection ends, or when an error counter reaches its maximum value, statistics on link usage are recorded. These statistics include information such as the adapter number, the date and time the link was established, and counts of errors and time-outs. This data is also logged in NMVT format if a connection has been specified for carrying NetView data, and is then sent if that connection and the server that owns that connection are both active.
Link statistics are generated when a link is closed or when one of the wrap counters listed later in this section is about to wrap. Whenever a link statistics message is built, all the wrap counters are reset to 0. The cumulative counters are not reset, and provide statistics from the point at which the particular link service was started.
The NMVT generated has the following format:
NMVT Header | |
41 03 8D 00 00 00 00 00 | NMVT Header |
Major Vector Header | |
00 69 | Length of major vector |
00 25 | Link Statistics major vector |
Data Link Traffic Counters Subvector | |
65 9A | Data Link Traffic Counters subvector |
03 | DLC type: SDLC |
hh | Adapter number (01+04) |
Date/Time Link Established | |
hh | Date |
hh | Month |
hh hh | Year |
hh | Hour |
hh | Minute |
hh | Second |
hh | Hundredths of a second |
hh | Counter |
Wrap Counters | |||
hh | Transmit I-frames OK | ||
hh | Transmit I-frames not OK | ||
hh | Retransmit I-frames | ||
hh | Received I-FCS OK | ||
hh | Received I-FCS not OK | ||
hh | Total frames sent | ||
00 | Reserved | ||
hh | Lost data frames received | ||
hh | FRMR conditions sent | ||
00 | Reserved | ||
hh | CTS drop | ||
00 | Reserved | ||
00 | Reserved | ||
hh | DSR drop out | ||
hh | Inactivity timeouts | ||
00 | Reserved | ||
hh | DMA underruns | ||
00 | Reserved | ||
hh | Transmit fail timeouts | ||
00 | Reserved | ||
The cumulative counters are the same counters as the wrap counters, with reserved bytes in the same positions.