In the past, there have been misinterpretations of the MIB as to when a string of octets should contain printable characters, meant to be displayed to a human. As a textual convention in the MIB, the datatype
DisplayString ::= OCTET STRING
is introduced. A DisplayString is restricted to the NVT ASCII character set, as defined in pages 10-11 of [6].
The following objects are now defined in terms of DisplayString:
sysDescr ifDescr
It should be noted that this change has no effect on either the syntax nor semantics of these objects. The use of the DisplayString notation is merely an artifact of the explanatory method used in MIB-II and future MIBs.
Further it should be noted that any object defined in terms of OCTET STRING may contain arbitrary binary data, in which each octet may take any value from 0 to 255 (decimal).