NIF (Neighbor Information Frames)

These are the most common frames displayed when you run pf_smtmon(1M) or nf_smtmon(1M). As the name suggests, they carry information about a neighboring station (for example, address, description, state, MAC capabilities) and are used as keep-alive notifications that a station is still attached to the ring and functioning. An NIF frame can be an announcement, a request, or a response.