CentreCOM 3600 Series Hub/Repeaters
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Statistics Database
Omega maintains a database of statistical data on physical and datalink layer
activities. It is actually a distributed database—portions of the database
reside within each module of a hub.
The Statistics Database complies with standards for Hub MIBs from the
IEEE and the TCP community. Each manageable AT-3600 Series Repeater
module maintains a collection of statistics counters on a per-port basis. On a
multi-module hub, the various ports are organized into “groups” (a MIB
concept), where each group represents one module.
The management agent maintains the counters listed in Table 5 in the
Statistics Database on a per-port, per-module basis:
Table 5:
Statistics Database Per-Port Counters
Good Frames
Frames (packets) received without error.
CRC Errors
Frames with a Cyclic Redundancy Check (CRC) error, but with the
proper length (64-1518 bytes) and no Collision or Alignment
Error occurrences.
Alignment Errors
Frames with a non-integral number of bytes (i.e., the frame length
in bits was not evenly divisible by 8), but with the proper length
(64-1518 bytes).
Runts
Frames less than the Ethernet/IEEE 802.3 minimum frame length
(64 bytes including the CRC).
Long Frames
Frames greater than the Ethernet/IEEE 802.3 maximum frame
length (1518 bytes including the CRC).
Bad Frames
The sum of CRC Errors, Alignment Errors, Runts, and Long
Frames.
Total Frames
The sum of Good Frames and Bad Frames.
Short Events
Frame fragments less than 74 bits in length.
Port Collisions
Frames with a collision occurring external to the AT-3600 module
(an Ethernet collision signal detected); i.e., an AT-3600 port
attempted to transmit at the same time as some other device
external to the AT-3600.
Late Collisions
Port collisions that occurred after 64 byte-times of the frame had
elapsed.
Port Partitions
The number of times the port was automatically partitioned Off
Line.
Data Rate
Mismatches
Frames transmitted at a data rate outside of Ethernet/IEEE 802.3
specifications.
