ifMainType 1.3.6.1.4.1.207.1.4.166.27.1.4.1.2

The type/protocol of interface. Specification of the object is mandatory for all interfaces. This value should be specified after the row creation in the ifMainTable and before setting any other object in this table. Once the type is specified, it cannot be changed - the interface should be deleted for changing the type of the interface. The ethernetCsmacd(6), iso88025TokenRing(9), aal5(49), async(84) and hdlc(118) are physical interfaces while all other types are virtual or logical interfaces. For creation of physical interface types, it is mandatory to specify the handle to the device driver using the ifAlias object of the standard ifXTable before specifying the type. This handle could be something like eth1 or /dev/abcd.