Cabletron Systems 7000 manual Table index.lengthin bytes.instancein decimal format

Alarm Configuration

Be sure you define your instance values carefully; if you neglect to set the instance correctly, you will receive the “Set failed; ensure variable is readable”

error message when you click to set your alarm.

NOTE

If you wish to set an alarm on an object whose instance is non-integral Ñ for example, a Host Table object indexed by MAC address Ñ or on an object with multiple indices, like a Matrix Table entry (which is indexed by a pair of MAC addresses), you must follow certain special procedures for deÞning the instance. For these OIDs, the instance deÞnition must take the following format:

table index.length(in bytes).instance(in decimal format)

For the Þrst 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, deÞne the Þrst byte of the instance as the index number assigned to the speciÞc Host Table you want to check. These index numbers are assigned automatically as the table entries are created; no two tables Ñ even if they are on different interfaces Ñ 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 Ñ a six-byte value.

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 Þrst digit of the two-digit hex number by 16, then add the value of the second digit. (For hex values represented by alphabetical characters, remember that a=10, b=11, c=12, d=13, e=14, and f=15.) A hex value of b7, for instance, is represented in decimal format as 16 x 11 + 7, or 183.

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 00-00-1d-aa-23-c9.

For objects with multiple indices Ñ such as objects in a matrix table Ñ you must add additional length and index information to the instance deÞnition, 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 00-00-1d-aa-23-c9; 6=the length in bytes of the next index; and 0.0.29.10.20.183=the decimal format for MAC address 00-00-1d-0a-14-b7.

Additional instance issues may exist for FDDI objects; if youÕre unsure how to assign an instance, use the MIBTree utility to query the object of interest, and note the appropriate instancing on the returned values.

Advanced Alarm Configuration 4-17