Alarm Limits 5-21
Managing Ethernet MicroLAN Modules
Packets
Use the text box in this field to determine the total number of packets (including all errors
except collisions) that must be processed by the repeater, board, or port within the
user-specified time before an alarm is triggered. Allowable values are 1 to Ý 4 billion
(232-1).
Broadcast Packets
Use the text box in this field to determine the number of broadcast packets that must be
processed by the repeater, board, or port within the user-specified time before an alarm
limit is reached. Allowable values are 1 to Ý 4 billion (232-1).
% Errors of Type
Use the text box in this field to determine what percentage of packets received by the
repeater, board, or port within the specified time interval can be errors of the selected type
or types before an alarm is triggered. Allowable values are one to 100; percentages will be
calculated based on the number of error packets of all types selected (all those with an
check in their check box). Again, a repeater-level alarm will count all selected error types
received by the repeater channel; a port-level alarm will count only selected error types
received by the individual port. (Remember, on an Ethernet MicroLAN module, a board is
equivalent to a repeater channel.)
You can select any combination of the following error types:
CRC Errors If this check box is selected, all packets with Cyclical
Redundancy Check (CRC) errors will be included in
calculating the overall percentage of errors.
Framing Errors If this check box is selected, all misaligned packets will be
included in calculating the overall percentage of errors. A
misaligned packet is one with a non-integral number of bytes;
these are also sometimes referred to as alignment errors.
Runts If this check box is selected, the number of runt packets will be
included in calculating the overall percentage of errors. A runt
packet is one that is less than the minimum Ethernet frame size
of 64 bytes.
OOW Collisions If this check box is selected, all collisions out of the standard
collision window (51.2 µs) will be included in calculating the
overall percentage of errors. Out-of-window collisions are
typically caused by faulty network design.
Giants If this check box is selected, the number of giant packets will
be included in calculating the overall percentage of errors. A
giant packet exceeds the maximum Ethernet frame size of 1518
bytes (excluding the preamble).