H3C Technologies H3C SecBlade NetStream Cards - Manual (Page 309)

294
• Using RMON probes. Management devices can obtain management information from RMON
probes directly and control network resources. In this approach, management devices can obtain
all RMON MIB information.
• 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 by using basic
SNMP operations to gather network management information, which, due to system resources
limitation, only covers four groups of MIB information, alarm, event, history, and statistics, in most
cases.
The H3C device adopts the second way and realizes the RMON agent function. With the RMON agent
function, the management device can obtain the traffic that flow among the managed devices on each
connected network 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 describes the five kinds of groups in general.
Ethernet statistics group
The statistics group defines that the system collects statistics of 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 of traffic information on an
interface and saves the statistics in the history record table (ethernetHistoryTable) for query convenience
of the management device. The statistics include 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 at 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:
• 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.
• Trap: Sending a trap to notify the occurrence of this event to the network management station
(NMS).
• Log-Trap: Logging event information in the event log table and sending a trap to the NMS.
• None: No action.