07-RMON Configuration
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Configuring the RMON Statistics Function·
Configuring the RMON Ethernet Statistics Function
Configuring the RMON History Statistics Function
Configuring the RMON Alarm Function
Displaying and Maintaining RMON
When configuring RMON, go to these sections for information you are interested in:
l Configuring the RMON Statistics Function
l Configuring the RMON Alarm Function
l Displaying and Maintaining RMON
This section covers these topics:
The remote monitoring (RMON) is used to realize the monitoring and management from the management devices to the managed devices on the network by implementing such functions as statistics and alarm. The statistics function enables a managed device to periodically or continuously track various traffic information on the network segments connecting to its ports, such as total number of received packets or total number of oversize packets received. The alarm function enables the managed device to monitor the value of a specified MIB variable, log the event and send traps to the management device when the value reaches the threshold, such as the port rate reaches a certain value or the potion of broadcast packets received in the total packets reaches a certain value.
Both the RMON protocol and the simple network management protocol (SNMP) are used for remote network management:
l The RMON is implemented on the basis of the SNMP, which is thus enhanced. RMON sends traps to the management device to notify the abnormality of the alarm variables by using the SNMP trap packet sending mechanism. Although trap is also defined in SNMP, it usually used to notify the management device whether some functions on the managed device operate normally and the change of physical status of interfaces. Traps in RMON and in SNMP have different monitored targets, triggering conditions, and report contents.
l RMON provides an efficient means of monitoring subnets and allows SNMP to monitor remote network devices in a more proactive and effective way. The RMON protocol defines that when the alarm threshold is reached, the managed device send traps automatically, so the management device has no need to get the values of MIB variables and compare them for multiple times, and thus greatly reducing the communication traffic between the management device and the managed devices. In this way, you can manage a large scale of network easily and effectively.
RMON allows multiple monitors. A monitor provides two ways of data gathering:
l 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.
l 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.
The device adopts the second way and realizes the RMON agent function. By using this function, the management devices can obtain information about traffic size, error statistics, and performance statistics for network management.
Among the RMON groups defined by RMON specifications (RFC 2819), the realized public MIB of the device supports the event group, alarm group, history group and statistics group. 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.
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:
l 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.
l Trap: Sending traps to notify the occurrence of this event to the network management stations (NMSs).
l Log-Trap: Logging event information in the event log table and sending traps to NMSs.
l None: No action
The RMON alarm group monitors specified alarm variables, such as total number of received packets (etherStatsPkts) on a port. After you define an alarm entry the system gets the value of the monitored alarm variable at the specified interval, when the value of the monitored variable is greater than or equal to the upper threshold, an upper event is triggered; when the value of the monitored variable is smaller than or equal to the lower threshold, a lower event is triggered. The event is then handled as defined in the event group.
If a sampled alarm variable overpasses the same threshold multiple times, only the first one can cause an alarm event. That is, the rising alarm and falling alarm are alternate.
The private alarm group calculates the values of alarm variables and compares the result with the defined threshold, thereby realizing a more comprehensive alarming function.
System handles the prialarm alarm table entry (as defined by the user) in the following ways:
l Periodically samples the prialarm alarm variables defined in the prialarm formula.
l Calculates the sampled values based on the prialarm formula.
l Compares the result with the defined threshold and generates an appropriate event.
If the count result overpasses the same threshold multiple times, only the first one can cause an alarm event. That is, the rising alarm and falling alarm are alternate.
The history group defines that the system periodically collects statistics on traffic information at interfaces 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.
The history group collects statistics on packets received on the interface during each period, which can be configured through the command line.
The statistics group defines that the system collects statistics on various traffic information on the 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 and transmitted, packets received and transmitted, and so on.
After the creation of a statistics entry on an interface, the statistics group starts to collect traffic statistics on the current interface. The result of the statistics is a cumulative sum.
RMON statistics function can be implemented by either the Ethernet statistics group or the history group, but the objects of the statistics are different, you can choose one from them accordingly.
l The statistics object of the Ethernet statistics group is the variable defined in the Ethernet statistics table, and the recorded content is a cumulative sum of the variable from the time the statistics entry is created to the current time. For detailed configuration, refer to Configuring the RMON Ethernet Statistics Function.
l The statistics object of the history group is the variable defined in the history record table, and the recorded content is a cumulative sum of the variable in each period. For detailed configuration, refer to Configuring the RMON History Statistics Function.
Follow these steps to configure the RMON Ethernet statistics function:
|
To do… |
Use the command… |
Remarks |
|
Enter system view |
system-view |
— |
|
Enter Ethernet interface view |
interface interface-type interface-number |
— |
|
Create an entry in the RMON statistics table |
rmon statistics entry-number [ owner text ] |
Required |
l Only one statistics entry can be created on one interface.
l You can create up to 100 statistics entries for the device.
Follow these steps to configure the RMON history statistics function:
|
To do… |
Use the command… |
Remarks |
|
Enter system view |
system-view |
— |
|
Enter Ethernet interface view |
interface interface-type interface-number |
— |
|
Create an entry in the RMON history control table |
rmon history entry-number buckets number interval sampling-interval [ owner text ] |
Required |
l The entry-number must be globally unique and cannot be used on another interface; otherwise, the operation fails.
l You can configure multiple history entries on one interface, but the values of the entry-number arguments must be different, and the values of the sampling-interval arguments must be different too; otherwise, the operation fails.
l You can create up to 100 history entries for the device.
l When you create an entry in the history table, if the specified buckets number argument exceeds the history table size supported by the device, the entry will be created. However, the validated value of the buckets number argument corresponding to the entry is the history table size supported by the device.
l If you need to configure that the managed devices send traps to the NMS when it triggers an alarm event, you should configure the SNMP agent as described in SNMP Configuration in the System Volume before configuring the RMON alarm function.
l If the alarm variable is the MIB variable defined in the history group or the Ethernet statistics group, you must make sure that the RMON Ethernet statistics function or the RMON history statistics function is configured on the monitored Ethernet interface; otherwise, the creation of the alarm entry fails, and no alarm event is triggered.
Follow these steps to configure the RMON alarm function:
|
To do… |
Use the command… |
Remarks |
|
Enter system view |
system-view |
— |
|
Create an event entry in the event table |
rmon event entry-number [ description string ] { log | log-trap log-trapcommunity | none | trap trap-community } [ owner text ] |
Required |
|
Create an entry in the alarm table |
rmon alarm entry-number alarm-variable sampling-interval { absolute | delta } rising-threshold threshold-value1 event-entry1 falling-threshold threshold-value2 event-entry2 [ owner text ] |
Required Use at least one command. |
|
Create an entry in the private alarm table |
rmon prialarm entry-number prialarm-formula prialarm-des sampling-interval { absolute | changeratio | delta } rising-threshold threshold-value1 event-entry1 falling-threshold threshold-value2 event-entry2 entrytype { forever | cycle cycle-period } [ owner text ] |
l A new entry cannot be created if its parameters are identical with the corresponding parameters of an existing entry Refer to Table 1-1 for the parameters to be compared for different entries.
l The system limits the total number of each type of entries (Refer to Table 1-1 for the detailed numbers). When the total number of an entry reaches the maximum number of entries that can be created, the creation fails.
Table 1-1 Restrictions on the configuration of RMON
|
Entry |
Parameters to be compared |
Maximum number of entries that can be created |
|
Event |
Event description (description string), event type (log, trap, logtrap or none) and community name (trap-community or log-trapcommunity) |
60 |
|
Alarm |
Alarm variable (alarm-variable), sampling interval (sampling-interval), sampling type (absolute or delta), rising threshold (threshold-value1) and falling threshold (threshold-value2) |
60 |
|
Prialarm |
Alarm variable formula (alarm-variable), sampling interval (sampling-interval), sampling type (absolute, changeratio or delta), rising threshold (threshold-value1) and falling threshold (threshold-value2) |
50 |
|
To do… |
Use the command… |
Remarks |
|
Display RMON statistics |
display rmon statistics [ interface-type interface-number ] |
Available in any view |
|
Display the RMON history control entry and history sampling information |
display rmon history [ interface-type interface-number ] |
Available in any view |
|
Display RMON alarm configuration information |
display rmon alarm [ entry-number ] |
Available in any view |
|
Display RMON prialarm configuration information |
display rmon prialarm [ entry-number ] |
Available in any view |
|
Display RMON events configuration information |
display rmon event [ entry-number ] |
Available in any view |
|
Display log information for the specified or all event entries. |
display rmon eventlog [ entry-number ] |
Available in any view |
Agent is connected to a configuration terminal through its console port and to a remote NMS across the Internet.
Create an entry in the RMON Ethernet statistics table to gather statistics on GigabitEthernet1/0/1, and enable logging after received bytes exceed the specified threshold.
Figure 1-1 Network diagram for RMON
# Configure RMON to gather statistics for interface GigabitEthernet1/0/1.
<Sysname> system-view
[Sysname] interface gigabitethernet 1/0/1
[Sysname-GigabitEthernet1/0/1] rmon statistics 1 owner user1-rmon
[Sysname-GigabitEthernet1/0/1] quit
# Display RMON statistics for interface GigabitEthernet1/0/1.
<Sysname> display rmon statistics gigabitethernet 1/0/1
EtherStatsEntry 1 owned by user1-rmon is VALID.
Interface : GigabitEthernet1/0/1<ifIndex.3>
etherStatsOctets : 21657 , etherStatsPkts : 307
etherStatsBroadcastPkts : 56 , etherStatsMulticastPkts : 34
etherStatsUndersizePkts : 0 , etherStatsOversizePkts : 0
etherStatsFragments : 0 , etherStatsJabbers : 0
etherStatsCRCAlignErrors : 0 , etherStatsCollisions : 0
etherStatsDropEvents (insufficient resources): 0
Packets received according to length:
64 : 235 , 65-127 : 67 , 128-255 : 4
256-511: 1 , 512-1023: 0 , 1024-1518: 0
# Create an event to start logging after the event is triggered.
<Sysname> system-view
[Sysname] rmon event 1 log owner 1-rmon
# Configure an alarm group to sample received bytes on GigabitEthernet1/0/1. When the received bytes exceed the upper or below the lower limit, logging is enabled.
[Sysname] rmon alarm 1 1.3.6.1.2.1.16.1.1.1.4.1 10 delta rising-threshold 1000 1 falling-threshold 100 1 owner 1-rmon
[Sysname] display rmon alarm 1
AlarmEntry 1 owned by 1-rmon is VALID.
Samples type : delta
Variable formula : 1.3.6.1.2.1.16.1.1.1.4.1<etherStatsOctets.1>
Sampling interval : 10(sec)
Rising threshold : 1000(linked with event 1)
Falling threshold : 100(linked with event 1)
When startup enables : risingOrFallingAlarm
