3.1.5 Message Processing Events and Sequencing Rules
The enumerator only processes messages received on the network interface identified by the Network Interface Identifier. It ignores all other messages.
When an enumerator receives an LLTD frame, it MUST check the header of this protocol to determine whether it is a valid Hello frame, and it must also check whether the DiscoverFrameSent flag is TRUE, which indicates that the enumerator has solicited a response from responders. If either condition is not met, the message MUST be ignored.