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Vendor Namespace

Bit Number
not applicable, bit 30 in every it_present word
u8 OUI[3], u8 sub_namespace, u16 skip_length
Required Alignment

This field is reserved in all namespaces and every it_present word, the standard radiotap namespace as well as all vendor namespaces. It is mutually exclusive with the Reset to Radiotap Namespace field, setting both is undefined.

The Vendor Namespace Field contains three sub-fields. The first sub-field is 3 bytes long. It contains the vendor’s IEEE 802 Organizationally Unique Identifier (OUI). The fourth byte is a vendor-specific “namespace selector.”

Before it resumes interpretation of presence bits in the following 32-bit presence words, if any, the interpreter shall reset its presence-bitmap index to 0, and change to the vendor namespace specified by the OUI and selector.

The fifth and sixth bytes, skip_length, comprise a 16 bit little-endian value that tells the interpreter how many bytes of data after the end of the Vendor Namespace Field can only be interpreted according to the vendor namespace. If a radiotap header changes to a namespace that the interpreter does not understand, and back, the interpreter may resume interpretation in the new namespace by skipping skip_length data bytes after the end of the Vendor Namespace Field. If a radiotap header changes from a vendor namespace to another vendor namespace, the 6-byte data describing the new vendor namespace shall not be accounted for in skip_length.