4.1.7. Mapping of the DEFVAL clause

The DEFVAL clause, which need not be present, defines an acceptable default value which may be used when an object instance is created at the discretion of the agent acting in conformance with the third paradigm described in Section 4.2 above.

During conceptual row creation, if an instance of a columnar object is not present as one of the operands in the correspondent SNMP set operation, then the value of the DEFVAL clause, if present, indicates an acceptable default value that the agent might use.

The value of the DEFVAL clause must, of course, correspond to the SYNTAX clause for the object. Note that if an operand to the SNMP set operation is an instance of a read-only object, then the error noSuchName will be returned. As such, the DEFVAL clause can be used to provide an acceptable default value that the agent might use.

It is possible that no acceptable default value may exist for any of the columnar objects in a conceptual row for which the creation of new object instances is allowed. In this case, the objects specified in the INDEX clause must have a corresponding ACCESS clause value of read-write.

By way of example, consider the following possible DEFVAL clauses:

       ObjectSyntax            DEFVAL clause
       -----------------       ------------
       INTEGER                 1 -- same for Counter, Gauge, TimeTicks
       OCTET STRING            'ffffffffffff'h
       DisplayString           "any NVT ASCII string"
       OBJECT IDENTIFIER       sysDescr
       OBJECT IDENTIFIER       { system 2 }
       NULL                    NULL
       NetworkAddress          { internet 'c0210415'h }
       IpAddress               'c0210415'h -- 192.33.4.21