DELL N3000 User Manual

Monitoring Switch Traffic

The RMON agent in the switch supports the following groups:

• Group 1—Statistics. Contains cumulative traffic and error statistics.
• Group 2—History. Generates reports from periodic traffic sampling that 

are useful for analyzing trends.

• Group 3 —Alarm. Enables the definition and setting of thresholds for 

various counters.  Thresholds can be passed in either a rising or falling 

direction on existing MIB objects, primarily those in the Statistics group.  

An alarm is triggered when a threshold is crossed and the alarm is passed to 

the Event group.  The Alarm requires the Event Group.

• Group 9 —Event. Controls the actions that are taken when an event 

occurs.  RMON events occur when:
–

A threshold (alarm) is exceeded

–

There is a match on certain filters.

Port mirroring is used to monitor the network traffic that a port sends and 

receives. The Port Mirroring feature creates a copy of the traffic that the 

source port handles and sends it to a destination port. The source port is the 

port that is being monitored. The destination port is where you would 

connect a network protocol analyzer to learn more about the traffic that is 

handled by the source port. Dell Networking switches support RSPAN 

destinations where traffic can be tunneled across the operational network.
A port monitoring session includes one or more source ports that mirror 

traffic to a single destination port. Sources can include VLANs, physical 

interfaces, port-channels, the internal CPU port, or IP or MAC ACL flows. 

Certain sources are not supported; i.e., physical members of a port-channel, 

VLANs that contain a LAG member, etc. Destination ports, once configured, 

no longer participate in spanning tree, IGMP/MLD snooping, or GVRP; do 

not learn MAC addresses (learned MAC addresses are purged); do not 

participate in routing (route entries are purged); and do not utilize any static 

filter configuration. Configuration of a destination port is restored when the 

port is no longer configured as a destination port.

The switch supports RMON1.