H3C Technologies H3C WX6000 Series Access Controllers - Manual (Page 106)

9-2
z Embedding RMON agents in network devices such as routers, switches, and hubs to provide the
RMON probe function. Management devices exchange data with RMON agents using basic SNMP
operations to gather network management information, which, due to system resources limitation,
may not cover all MIB information but four groups of information, alarm, event, history, and
statistics, in most cases.
H3C devices adopt the second way and realize the RMON agent function. With the RMON agent
function, the management device can monitor all the traffic sent and received between the managed
devices on all connected LAN segments; obtain information about error statistics and performance
statistics for network management.
RMON Groups
Among the RMON groups defined by RMON specifications (RFC 2819), the device has realized the
statistics group, history group, event group, and alarm group supported by the public MIB. Besides,
H3C also defines and implements the private alarm group, which enhances the functions of the alarm
group. This section briefly describes the five kinds of groups.
Ethernet statistics group
The statistics group defines that the system collects statistics on various traffic information on an
interface (at present, only Ethernet interfaces are supported) and saves the statistics in the Ethernet
statistics table (ethernetStatsTable) for query convenience of the management device. It provides
statistics about network collisions, CRC alignment errors, undersize/oversize packets, broadcasts,
multicasts, bytes received, packets received, and so on.
After the creation of a statistics entry on an interface, the statistics group starts to collect traffic statistics
on the interface. The result of the statistics is a cumulative sum.
History group
The history group defines that the system periodically collects statistics on traffic information on an
interface and saves the statistics in the history record table (ethernetHistoryTable) for query
convenience of the management device. The statistics data includes bandwidth utilization, number of
error packets, and total number of packets.
A history group collects statistics on packets received on the interface during each period, which can be
configured through the command line interface (CLI).
Event group
The event group defines event indexes and controls the generation and notifications of the events
triggered by the alarms defined in the alarm group and the private alarm group. The events can be
handled in one of the following ways:
z Log: Logging event related information (the occurred events, contents of the event, and so on) in
the event log table of the RMON MIB of the device, and thus the management device can check the
logs through the SNMP Get operation.
z Trap: Sending a trap to notify the occurrence of this event to the network management station
(NMS).
z Log-Trap: Logging event information in the event log table and sending a trap to the NMS.
z None: No action