For the benefit of row-creation in "conceptual" (see [9]) tables, DEFVAL (Default Value) clauses are included in the definitions in section 3, suggesting values which an agent should use for instances of variables which need to be created due to a Set-Request, but which are not specified in the Set-Request. DEFVAL clauses have not been specified for some objects which are read-only, implying that they are zeroed upon row creation. These objects are of the SYNTAX Counter32 or Gauge32.
For those objects not having a DEFVAL clause, both management stations and agents should heed the Robustness Principle of the Internet (see RFC-791):
"be liberal in what you accept, conservative in what you send"
That is, management stations should include as many of these columnar objects as possible (e.g., all read-write objects) in a Set-Request when creating a conceptual row; agents should accept a Set-Request with as few of these as they need (e.g., the minimum contents of a row creating SET consists of those objects for which, as they cannot be intuited, no default is specified.).
There are numerous read-write objects in this MIB, as it is designed for SNMP management of the protocol, not just SNMP monitoring of its state. However, in the absence of a standard SNMP Security architecture, it is acceptable for implementations to implement these as read-only with an alternative interface for their modification.