A string of octets containing one bit per VLAN for a
total of 4096 VLANs in the management domain.
The most significant bit of the octet string is the
lowest value VLAN of 4096 VLANs.
By setting the bit(1) we indicate that the vlan is part of the
interface.
The most significant bit of the bitmap is transmitted
first. Note that if the length of this string is less than
512 octets, any 'missing' octets are assumed to contain
the value zero.
This object provides default switch port value if
ifExtIsMonitoring is true(1).
This object is deprecated in favour of
ifExtNTrunkAllowedVlanList.