if Specific

1.3.6.1.2.1.2.2.1.22

A reference to MIB definitions specific to the particular media being used to realize the interface. It is recommended that this value point to an instance of a MIB object in the media-specific MIB, i.e., that this object have the semantics associated with the InstancePointer textual convention defined in RFC 1903. In fact, it is recommended that the media- specific MIB specify what value ifSpecific should/can take for values of ifType. If no MIB definitions specific to the particular media are available, the value should be set to the OBJECT IDENTIFIER { 0 0 }.