Attribute to determine which frames are to be forwarded to this port intact. 1 - Need To Know is not available. 2 - All frames. 3 - Frames addressed to the authorized devices only. 4 - Frames addressed to the authorized devices, plus all broadcast frames. 5 - Frames addressed to the authorized devices, plus all broadcast and multicast frames. 6 - As 3 and cannot be changed. 7 - As 4 and cannot be changed. 8 - As 5 and cannot be changed. 9 - Similar to needToKnowWithMulticastsAllowed, but no frames are allowed when the port has no online users. If this object returns 1,6,7 or 8, it means that the Need To Know configuration cannot be changed, and any attempt to write to this object will cause an error.