Table Of Contents

Configuring RMON

Understanding How RMON Works

Enabling RMON

Viewing RMON Data

Supported RMON and RMON2 MIB Objects

Configuring RMON

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This chapter describes how to configure RMON on the Catalyst enterprise LAN switches.

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Note For complete syntax and usage information for the commands used in this chapter, refer to the Command Reference—Catalyst 4000 Family, Catalyst 2948G, and Catalyst 2980G Switches.

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This chapter consists of these major sections:

•Understanding How RMON Works

•Enabling RMON

•Viewing RMON Data

•Supported RMON and RMON2 MIB Objects

Understanding How RMON Works

RMON is an Internet Engineering Task Force (IETF) standard monitoring specification that allows various network agents and console systems to exchange network monitoring data. The supervisor engine software provides embedded support for these components of the RMON specification (see the "Supported RMON and RMON2 MIB Objects" section for details):

•The following RMON groups are defined in RFC 1757:

–Statistics (RMON group 1) for Ethernet, Fast Ethernet, Fast EtherChannel, and Gigabit Ethernet switch ports (uses 140 bytes of supervisor engine module RAM per port)

–History (RMON group 2) for Ethernet, Fast Ethernet, Fast EtherChannel, and Gigabit Ethernet switch ports (uses 3 KB of supervisor engine module RAM for the first 50 buckets; each additional bucket uses another 56 bytes)

–Alarm (RMON group 3; each alarm configured uses 1.3 KB of supervisor engine RAM)

–Event (RMON group 9; each event configured uses 1.3 KB of supervisor engine RAM)

•The following RMON2 groups are defined in RFC 2021:

–UsrHistory (RMON2 group 18)

–ProbeConfig (RMON2 group 19)

The embedded RMON agent allows the switch to monitor network traffic from all ports simultaneously at the data-link layer of the OSI model without requiring a dedicated monitoring probe or network analyzer.

Enabling RMON

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Note RMON is disabled by default.

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To enable RMON, perform this procedure in privileged mode:

	Task	Command
Step 1	Enable RMON on the switch.	set snmp rmon enable
Step 2	Verify that RMON is enabled.	show snmp

This example shows how to enable RMON on the switch and how to verify that RMON is enabled:

Console> (enable) set snmp rmon enable

SNMP RMON support enabled.

Console> (enable) show snmp

RMON:                       Enabled

Extended RMON:              Extended RMON module is not present

Traps Enabled: 

Port,Module,Chassis,Bridge,Repeater,Vtp,Auth,ippermit,Vmps,config,entity,stpx

Port Traps Enabled: 1/1-2,4/1-48,5/1

Community-Access     Community-String    

----------------     --------------------

read-only            Everyone

read-write           Administrators

read-write-all       Root

Trap-Rec-Address                           Trap-Rec-Community

----------------------------------------   --------------------

172.16.10.10                               read-write

172.16.10.20                               read-write-all

Console> (enable)

Viewing RMON Data

Access to RMON data is available only on an NMS that supports RFC 1757 and RFC 1513 (see the "Using CiscoWorks2000" section). You cannot access RMON data through the switch CLI; however, CLI show commands provide similar information (refer to the Command Reference—Catalyst 4000 Family, Catalyst 2948G, and Catalyst 2980G Switches).

Supported RMON and RMON2 MIB Objects

Table 25-1 lists the RMON and RMON2 MIB objects supported by the supervisor engine software.

Table 25-1 Supervisor Engine RMON and RMON2 Support  

Module	Object Identifier (OID)	Definition	Source
Supervisor engine	...mib-2(1).rmon(16).statistics(1).etherStatsTable(1)	Counters for packets, octets, broadcasts, errors, etc.	RFC 1757
Supervisor engine	...mib-2(1).rmon(16).history(2).historyControlTable(1) ...mib-2(1).rmon(16).history(2).etherHistoryTable(2)	Periodically samples and saves statistics group counters for later retrieval.	RFC 1757 RFC 1757
Supervisor engine	...mib-2(1).rmon(16).alarm(3)	A threshold set on critical RMON variables for network management.	RFC 1757
Supervisor engine	...mib-2(1).rmon(16).event(9)	Generates SNMP traps when an Alarms group threshold is exceeded and logs the events.	RFC 1757
Supervisor engine	...mib-2(1).rmon(16).usrHistory(18)	Extends history beyond RMON1 link-layer statistics to include any RMON, RMON2, MIB-I, or MIB-II statistic.	RFC 2021
Supervisor engine	...mib-2(1).rmon(16).probeConfig(19)	Displays a list of agent capabilities and configurations.	RFC 2021