Monitoring Switch Traffic 411The 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 thatare useful for analyzing trends.• Group 3 —Alarm. Enables the definition and setting of thresholds forvarious counters. Thresholds can be passed in either a rising or fallingdirection on existing MIB objects, primarily those in the Statistics group.An alarm is triggered when a threshold is crossed and the alarm is passed tothe Event group. The Alarm requires the Event Group.• Group 9 —Event. Controls the actions that are taken when an eventoccurs. RMON events occur when:– A threshold (alarm) is exceeded– There is a match on certain filters.What is Port Mirroring?Port mirroring is used to monitor the network traffic that a port sends andreceives. The Port Mirroring feature creates a copy of the traffic that thesource port handles and sends it to a destination port. The source port is theport that is being monitored. The destination port is where you wouldconnect a network protocol analyzer to learn more about the traffic that ishandled by the source port. Dell Networking switches support RSPANdestinations where traffic can be tunneled across the operational network.A port monitoring session includes one or more source ports that mirrortraffic to a single destination port. Sources can include VLANs, physicalinterfaces, 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; donot learn MAC addresses (learned MAC addresses are purged); do notparticipate in routing (route entries are purged); and do not utilize any staticfilter configuration. Configuration of a destination port is restored when theport is no longer configured as a destination port.NOTE: The switch supports RMON1.
