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Enhancements
Release M.10.04 Enhancements
Operating Notes
■
To generate alerts for monitored events, you must enable the instrumentation monitoring
log and/or SNMP trap. The threshold for each monitored parameter is configurable and can
be adjusted to minimize false alarms (see
“Configuring Instrumentation Monitor” on page 73
).
■
When a parameter exceeds its threshold, an alert (event log message and/or SNMP trap) is
generated to inform network administrators of this condition. The following example shows
an event log message that occurs when the number of MAC addresses learned in the
forwarding table exceeds the configured threshold:
Figure 16. Example of Event Log Message generated by Instrumentation Monitor
ip-address-count
The number of destination IP addresses learned in the IP forwarding table. Some
attacks fill the IP forwarding table causing legitimate traffic to be dropped.
system-resource-usage
(Denial of Service logging)
The percentage of system resources in use. Some Denial-of-Service (DoS) attacks
will cause excessive system resource usage, resulting in insufficient resources for
legitimate traffic.
login-failures/min
The count of failed CLI login attempts or SNMP management authentication failures.
This indicates an attempt has been made to manage the switch with an invalid login
or password. Also, it might indicate a network management station has not been
configured with the correct SNMP authentication parameters for the switch.
port-auth-failures/min
The count of times a client has been unsuccessful logging into the network
system-delay
The response time, in seconds, of the CPU to new network events such as BPDU
packets or packets for other network protocols. Some DoS attacks can cause the
CPU to take too long to respond to new network events, which can lead to a
breakdown of Spanning Tree or other features. A delay of several seconds indicates
a problem.
mac-address-count
The number of MAC addresses learned in the forwarding table. Some attacks fill the
forwarding table so that new conversations are flooded to all parts of the network.
mac-moves/min
The average number of MAC address moves from one port to another per minute.
This usually indicates a network loop, but can also be caused by DoS attacks.
learn-discards/min
Number of MAC address learn events per minute discarded to help free CPU
resources when busy.
Parameter Name
Description
Standard Date/Time Prefix
for Event Log Messages
Monitored
Parameter
Threshold
Value
“inst-mon” label indicates an
Instrumentation Monitor event
Current
Value
W 05/27/06 12:10:16 inst-mon: Limit for MAC addr count (300) is exceeded (321)