Table of Contents

Chapter 1 RMON Configuration. 1-1

1.1 RMON Overview. 1-1

1.1.1 Introduction. 1-1

1.1.2 RMON Groups. 1-2

1.2 Configuring RMON. 1-3

1.2.1 Configuration Prerequisites. 1-3

1.2.2 Configuration Procedure. 1-3

1.3 Displaying and Maintaining RMON. 1-5

1.4 RMON Configuration Example. 1-6

 

Chapter 1  RMON Configuration

When configuring RMON, go to these sections for information you are interested in:

l           RMON Overview

l           Configuring RMON

l           Displaying and Maintaining RMON

l           RMON Configuration Example

1.1  RMON Overview

This section covers these topics:

l           Introduction

l           RMON Groups

1.1.1  Introduction

Remote Monitoring (RMON) is a type of IETF-defined MIB. It is the most important enhancement to the MIB II standard. It allows you to monitor traffic on network segments and even the entire network.

RMON is implemented based on the Simple Network Management Protocol (SNMP) and is fully compatible with the existing SNMP framework.

RMON provides an efficient means of monitoring subnets and allows SNMP to monitor remote network devices in a more proactive and effective way. It reduces traffic between network management station (NMS) and agent, facilitating large network management.

RMON comprises two parts: NMSs and agents running on network devices.

l           Each RMON NMS administers the agents within its administrative domain.

l           An RMON agent resides on a network monitor or probe for an interface. It monitors and gathers information about traffic over the network segment connected to the interface to provide statistics about packets over a specified period and good packets sent to a host for example.

RMON allows multiple monitors. A monitor provides two ways of data gathering:

l           Using RMON probes. NMSs can obtain management information from RMON probes directly and control network resources. In this approach, RMON NMSs 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. RMON NMSs exchange data with RMON agents with basic SNMP commands 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.

S9500 series adopts the second way. By using RMON agents on network monitors, an NMS can obtain information about traffic size, error statistics, and performance statistics for network management.

1.1.2  RMON Groups

RMON categorizes objects into ten groups. This section describes only the major implemented five groups.

I. 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:

l           Logging events in the event log table

l           Sending traps to NMSs

l           Both logging and sending traps

l           No action

II. Alarm group

The RMON alarm group monitors specified alarm variables, such as statistics on a port. If the sampled value of the monitored variable is bigger than or equal to the rising threshold, a rising alarm event is triggered; if the sampled value of the monitored variable is lower than or equal to the falling threshold, a falling alarm event is triggered. The event is then handled as defined in the event group.

The following is how the system handles entries in the RMON alarm table:

1)         Samples the alarm variables at the specified interval.

2)         Compares the sampled values with the predefined threshold and triggers events if all triggering conditions are met.

 

 

III. Private alarm group

The private alarm group calculates the sampled 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.

IV. History group

The history group controls the periodic statistical sampling of data, such as bandwidth utilization, number of errors, and total number of packets.

Note that each value provided by the group is a cumulative sum during a sampling period.

V. Ethernet statistics group

The statistics group monitors port utilization. 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 valid event entry on a specified interface, the Ethernet statistics group counts the number of packets received on the current interface. The result of the statistics is a cumulative sum.

 

 

1.2  Configuring RMON

1.2.1  Configuration Prerequisites

Before configuring RMON, configure the SNMP agent as described in SNMP Configuration in the System Volume.

1.2.2  Configuration Procedure

Follow these steps to configure RMON:

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 | trap trap-community | log-trap log-trapcommunity | none } [ owner text ]	Optional
Enter Ethernet interface view	interface interface-type interface-number	—
Create an entry in the history table	rmon history entry-number buckets number interval sampling-interval [ owner text ]	Optional
Create an entry in the statistics table	rmon statistics entry-number [ owner text ]	Optional
Exit Ethernet interface view	quit	—
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 ]	Optional
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 ]	Optional

 

 

Table 1-1 Limitations 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
History	Sampling interval (interval sampling-interval)	100
Statistics	Only one statistics entry can be created on an interface.	100
Alarm	Alarm variable (alarm-variable), sampling interval (sampling-interval), sampling type (absolute or delta), rising threshold (threshold-value1) and falling threshold (threshold-value2)	60
Pri-alarm	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

 

1.3  Displaying and Maintaining RMON

To do…	Use the command…	Remarks
Display RMON statistics	display rmon statistics [ interface-type interface-number ]	Available in any view
Display RMON history information and the latest 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 RMON event log information	display rmon eventlog [ event-number ]	Available in any view

 

1.4  RMON Configuration Example

I. Network requirements

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 GigabitEthernet 4/2/2, and logging is enabled after received bytes exceed the specified threshold.

II. Network diagram

Figure 1-1 Network diagram for RMON

III. Configuration procedure

# Configure RMON to gather statistics for interface GigabitEthernet 4/2/2.

<Sysname> system-view

[Sysname] interface GigabitEthernet 4/2/2

[Sysname-GigabitEthernet4/2/2] rmon statistics 1 owner user1-rmon

[Sysname-GigabitEthernet4/2/2] quit

# Display RMON statistics for interface GigabitEthernet 4/2/2.

<Sysname> display rmon statistics GigabitEthernet 4/2/2

Statistics entry 1 owned by user1-rmon is VALID.

  Interface : GigabitEthernet4/2/2<ifIndex.157>

  etherStatsOctets         : 0         , etherStatsPkts          : 0

  etherStatsBroadcastPkts  : 0         , etherStatsMulticastPkts : 0

  etherStatsUndersizePkts  : 0         , etherStatsOversizePkts  : 0

  etherStatsFragments      : 0         , etherStatsJabbers       : 0

  etherStatsCRCAlignErrors : 0         , etherStatsCollisions    : 0

  etherStatsDropEvents (insufficient resources): 0

  Packets received according to length:

  64     : 0         ,  65-127  : 0         ,  128-255  : 0

  256-511: 0         ,  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

[Sysname] display rmon event 1

Event table 1 owned by 1-rmon is VALID.

  Description: null.

  Will cause log when triggered, last triggered at 2day(s) 03h:56m:06s.

# Configure an alarm group.

[Sysname] rmon alarm 1 1.3.6.1.2.1.16.1.1.1.4.1 delta rising-threshold 1000 1 falling-threshold 100 1 owner 1-rmon

[Sysname] display rmon alarm 1

Alarm table 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

  Latest value          : 2552