
Alarm Configuration
NOTE |
If you wish to set an alarm on an object whose instance is
table index.length(in bytes).instance(in decimal format)
For the first byte of the instance, you must use the index number of the table which contains the OID you want to track. For example, to set an alarm on an object in the Host Table, define the first byte of the instance as the index number assigned to the specific Host Table you want to check. These index numbers are assigned automatically as the table entries are created; no two tables — even if they are on different interfaces — will share the same table index number.
Second, you must specify the length, in bytes, of the index you will be using. Again, in the case of an object in the Host Table, that value would be 6, since Host Table entries are indexed by MAC address — a
Finally, you must specify the index itself, in decimal format. In the case of a MAC address, that means you must convert the standard hexadecimal format to decimal format. To do this, simply multiply the first digit of the
So, for example, the instance for an object in the Hosts group might read as follows:
2.6.0.0.29.170.35.201
where 2=the host table index; 6=the length in bytes of the index to follow; and 0.0.29.170.35.201=the decimal format for MAC address
For objects with multiple indices — such as objects in a matrix table — you must add additional length and index information to the instance definition, as illustrated below:
3.6.0.0.29.170.35.201.6.0.0.29.10.20.183
where 3=the matrix table index; 6=the length in bytes of the index to follow; 0.0.29.170.35.201=the decimal format for MAC address
Additional instance issues may exist for FDDI objects; if you’re unsure how to assign an instance, use the MIB Tools utility to query the object of interest, and note the appropriate instancing on the returned values.
6.In the Alarm Interval field, enter the amount of time over which the selected variable will be sampled. At the end of the interval, the sample value will be compared to both the rising and falling thresholds. There is no practical limit to the size of the interval (as the maximum value is 24,855 days 3 hours 14 minutes and 7 seconds — over 68 years!); the default value is 1 minute.
Advanced Alarm Configuration |