Cabletron Systems 2000 3-18 Advanced Alarm Conguration, interface

Alarm Conﬁguration

3-18 Advanced Alarm Conﬁguration

5. Once you have selected the object you wish to use for your alarm variable,

you must assign the appropriate instance value in the Alarm Instance ﬁeld.

Most RMON objects are instanced by the index number assigned to the table

in which they reside; for example, if you wish to set an alarm on an object

located in an RMON Statistics table, you can determine the appropriate

instance by noting the index number assigned to the table that is collecting

data on the interface you’re interested in. In the case of the default tables,

index

numbers often mirror

interface

numbers; however, if there are multiple

default tables per interface, or if additional tables have been created, this may

not be true. (Table index numbers are assigned automatically as table entries

are created; no two tables — even those on different interfaces — will share

the same table index number.)

If you have selected an object from a table which is indexed by some other

means — for example, by ring number — you must be sure to assign the

instance accordingly. If you’re not sure how a tabular object is instanced, you

can use the MIBTree utility (described in the

Tools Guide

) to query the object;

all available instances for the object will be displayed. (Host and matrix table

objects — which are indexed by MAC address — require special handling;

see the Note which follows this step.)

If you have selected an object which is

not

part of a table, you must assign an

instance value of 0.

Be sure you deﬁne your instance values carefully; if you neglect to set the

instance correctly, you will receive the “Set failed; ensure v ariab le is readab le”

error message when you click the Apply button to set your alarm.

NOTE

If you select an object which is not resident in the device Þrmware, you will receive a ÒSet

Failed; ensure variable is readableÓ message when you try to set your alarm by clicking on

the Apply button. If you are unsure just which objects are resident on your device, and

you Þnd yourself receiving a lot of ÒSet FailedÓ messages, you can use the MIB Tools

utility (accessed from the main console window menu bar or from the Chassis View) to

determine which objects are and are not part of your deviceÕs Þrmware Ñ simply query

the object you are interested in; if the query response comes back empty, the object is not

present (make sure you are using the appropriate community name when making a query,

or you will get no response).

TIP

You can use the MIB Tree panel to determine which objects are tabular and which are not:

objects which are part of a table will descend from a blue folder (which will have a ÒTÓ on

it, and a name which will almost always include the word ÒtableÓ); objects which are not

will descend directly from a yellow folder. (Note: There may be one or more yellow

folders in between the blue folder which contains the table and the leaf object you wish to

use; however, those objects are still part of the table.)