100 SunFDDI/P1.0 Adapter User’s Guide—May 1997
8
SMT Frame Classes and Types
SMT frames are used for peer-to-peer (station-to-station) management. They
are divided into classes, which define the function of the frame. Each class is
then divided into up to three types, which define whether the frame is an
announcement (information only), a request for service, or a response to a
request. Refer to the ANSI/FDDI Station Management (SMT) X3.299 R7.3
Specification for a detailed description of SMT frames and their functions.
The pf_smtmon utility is used to monitor the following SMT frame classes:

NIF(Neighbor Information Frames)

These are the most common frames displayed when you run pf_smtmon.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.

SIF(Status Information Frames)

These frames carry more detailed information about a station. SIF
configuration frames describe the station configuration (for example, number
of ports, number of MAC entities, connection policy); SIF operation frames
describe the current status of the station. A SIF frame can be either a request
or a response.

ECF(Echo Frames)

These frames are equivalent to ICMP ping packets and are used to test
connectivity between stations. An ECF frame can be either a request or a
response.

RDF(Request Denied Frame)

These frames are used to indicate that the request is rejected. If an SMT agent
(such as the SunNet Manager proxyagent delivered with SunFDDI/P) receives
an unsupported or unrecognized request, it issues an RDF frame to indicate
that the request is rejected. An RDF frame is always a response.