RMON1 Groups

RMON agents gather nine groups of statistics, ten including Token Ring, which are forwarded to a manager on request, usually via SNMP. As summarized in Figure 3-30, RMON1 agents can implement some or all of the following groups:

■ Statistics: Contains statistics such as packets sent, bytes sent, broadcast packets, multicast packets, CRC errors, runts, giants, fragments, jabbers, collisions, and so forth, for each monitored interface on the device.

■ History: Used to store periodic statistical samples for later retrieval.

■ Alarm: Used to set specific thresholds for managed objects and to trigger an event on crossing the threshold (this requires an Events group).

■ Host: Contains statistics associated with each host discovered on the network.

■ Host Top N: Contains statistics for hosts that top a list ordered by one of their observed variables.

■ Matrix: Contains statistics for conversations between sets of two addresses, including the number of packets or bytes exchanged between two hosts.

■ Filters: Contains rules for data packet filters; data packets matched by these rules generate events or are stored locally in a Packet Capture group.

■ Packet Capture: Contains data packets that match rules set in the Filters group.

■ Events: Controls the generation and notification of events from this device.

■ TokenRing: Contains the following Token Ring Extensions:

— Ring Station—Detailed statistics on individual stations

— Ring Station Order—Ordered list of stations currently on the ring

— Ring Station Configuration—Configuration information and insertion/removal data on each station

— Source Routing—Statistics on source routing, such as hop counts Figure 3-30 RMON1 Groups statistics history alarm


Real Time—Current Statistics Statistics Over Time Predetermined Threshold Watch Tracks Individual Host Statistics

5 hostTopN "N" Statistically Most Active Hosts

A< >B—Conversation Statistics


Packet Structure and Content Matching

7 filters

8 packetCapture Collection for Subsequent Analysis

9 events Reaction to Predetermined Conditions


Token Ring—RMON Extensions

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