The NDREC trace table contains entries describing the
creation and update of a node record. It is located after the CV45
in an NDREC. It is pointed to by a trace pointer in the NDREC. The
first 8 bytes of the NDREC trace table is the header, which contains
the following information:
- Byte (hex)
- Contents
- 00–03
- The current RSN (resource sequence number) of the last update
to this NDREC. The current RSN is used when recording TDUs (topology
database updates) related to the NDREC. Because duplicate TDU information
can be received from multiple adjacent nodes, the RSN in the TDU is
compared to the current RSN in the NDREC trace. The TDU will be recorded
only in the NDREC trace if the RSN in the TDU is greater than the
current RSN in the NDREC trace, indicating that the information in
the TDU is more recent than that in the NDREC.
- 04–07
- Address of the current NDREC trace table entry. This is the last
trace entry where data was recorded.
Three NDREC trace table entries are displayed after the
header. The information about the creation of the NDREC is recorded
in the first NDREC trace entry. This entry remains unchanged for the
life of the NDREC. Recording of trace events will continue in the
remaining two trace table entries, with the trace wrapping back to
the second entry after the third entry is completed.