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This chapter describes the SNMP commands available from the command line interface (CLI) on a LightStream 2020 (LS2020) enterprise ATM switch. This chapter is intended for SNMP experts who use the commands to monitor and manipulate MIB objects. If you are not familiar with SNMP, it is recommended that you do not use these commands.
In some cases, SNMP commands may be long and repetitive. You can store sequences of SNMP commands in CLI script files and execute them using the source command described in the LightStream 2020 CLI Reference Manual.
The CLI provides the following SNMP commands:
The next sections include:
MIB object names are used to identify the MIB objects in the SNMP commands described in this chapter. MIB object names come from the standard or private MIBs that the LS2020 switch supports. For a detailed discussion of the MIB, see the LightStream 2020 CLI Reference Manual.
In addition to a MIB object name, you must use a MIB instance identifier to manipulate a particular MIB object. SNMP calculates a suffix based on the hierarchy of a MIB object and adds the suffix to the MIB object name to form its instance identifier. This use of instance identifiers allows all MIB object names to be unique.
For example, the MIB object sysDescr has only a single value. It is identified by its MIB object name (sysDescr) followed by its instance identifier (0), resulting in sysDescr.0.
A MIB object with multiple instances has a unique identifier for each instance. In the following examples, the number (1, 16, 24, or 43) following the MIB object pidName identifies the specific instance of pidName:
For a further discussion of instance identifiers, see The Simple Book: An Introduction to Management of TCP/IP-based Internets by Marshall T. Rose, 1991, Prentice Hall, Inc. (ISBN 0-13-812611-9).
If you are unsure of a MIB object name, use the walksnmp command with the specific object's MIB tree or subtree name as the command argument. (See "Walking a MIB Subtree" later in this chapter.) This displays all MIB objects below the specified point in the tree. Whenever the attribute MIB name or MIB address is required by a syntax statement, you must enter both the MIB object name and its instance identifier.
The procedures in this section tell you how to view the value of a particular MIB object using one of two different commands. Procedure 1 displays the value of the MIB object you specify. Procedure 2 displays the value of the MIB object following the MIB object you specify. The getnextsnmp command is useful if you don't know the exact structure of the MIB.
At the cli> prompt, enter:
cli> getsnmp <MIB name or address>
where
<MIB name or address> = Name or address of the MIB object you want information on. You may enter multiple names or addresses.
Some examples of the getsnmp command are
getsnmp sysDescr.0
getsnmp sysDescr.0 sysObjectID.0 sysUpTime.0
getsnmp 1.3.6.1.2.1.1.1.0
At the cli> prompt, enter:
cli> getnextsnmp <MIB name or address>
where
<MIB name or address> = Name or address of the MIB object just before the MIB object you want to get information on. You may enter multiple names or addresses.
When you enter getsnmp sysDescr.0, the following information appears:
cli> getsnmp sysDescr.0
Name: sysDescr.0 Value: LightStream 2020 ATM Switch
cli>
When you enter getnextsnmp sysDescr.0, the following information appears:
cli> getnextsnmp sysDescr.0
Name: sysObjectID.0 Value: LightStream 2020 ATM Switch
cli>
These steps tell you how to set the value of a MIB object using the setsnmp command. If you change a MIB object using this command, the change is not saved permanently to the hard disk. Instead, the changes are made to run-time memory. If you reboot the system, the changes made using this procedure are lost.At the cli> prompt, enter:
protected
Step 3 Enter the protected mode password when you see the following prompt:
Step 4 Set the SNMP community to a read/write community by entering the following at the *cli> prompt:
set snmp community <community name>
<community name> = The name of the SNMP community with read/write privileges that you want to access. (A switch can have several SNMP community names with read/write privileges.) The SNMP community must be set to a read/write community before you can set the MIB object value.
Step 5 At the *cli> prompt, enter:
setsnmp <MIB name or address> <value>
where
<MIB name or address> = Name or address of the MIB object you want to change. You may enter multiple names or addresses and their corresponding values.
<value> = The value of the MIB object you want to set.
For example, you can enter
setsnmp chassisId 4143
Whenever you issue a setsnmp command from CLI, it is automatically followed by a getsnmp command. See the information displayed by the getsnmp command to verify that the change you made is correct. After entering the command shown above, the following would be displayed:
To display a portion of the MIB subtree using the walksnmp command, you can enter the name of the subtree you want to "walk" through. This command displays all MIB objects (and their values) in that subtree. You can also use walksnmp to get a list of all the instances of a particular MIB object in the switch.
At the cli> prompt, enter:
cli> walksnmp <MIB name or address>
where
<MIB name or address> = The name or address of a MIB subtree or MIB object. (You must put the name in quotes if it contains non-alphanumeric characters)
For example, to walk the System subtree, enter:
cli> walksnmp system
or
cli> walk mib2
or
cli> walksnmp 1.3.6.1.2.1.1
To list the names of all the processes running in the LS2020 switch, enter:
cli> walksnmp pidName
When you enter walksnmp system, the following information is displayed.
cli> walksnmp system
Name: sysDescr.0 Value: ATM Data Switch
Name: sysObjectID.0 Value: SWITCH_SNMP_Agent
Name: sysUpTime.0 Value: 39501284
Name: sysContact.0 Value: Tom Matthews
Name: sysName.0 Value: emtb7
Name: sysLocation.0 Value: Cambridge
Name: sysServices.0 Value: 78
cli>
When you enter walksnmp pidName, the following information is displayed:
Name: pidName.8 Value: ndd
Name: pidName.9 Value: watchdog
Name: pidName.10 Value: mma
Name: pidName.16 Value: kernlog
Name: pidName.17 Value: cac
Name: pidName.18 Value: collector
Name: pidName.19 Value: mptmm
Name: pidName.20 Value: npcc
Name: pidName.21 Value: gidd
Name: pidName.23 Value: lcc
Name: pidName:24 Value: lcc
Name: pidName.25 Value: lcc
Name: pidName.33 Value: lcc
cli>
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