3Com 3C780 - LinkBuilder FDDI Base Unit User Manual page 166

PHY
Ping
PMD
Port
Physical Layer Protocol. The sublayer that describes the
medium-independent portion of the OSI Physical layer and
specifies the rules for encoding digital data for transmission
from one FDDI station to another. It also provides the link
between the PMD and the MAC layer.
Packet InterNet Groper. A program used in the Internet to find
out whether or not a host on the network is operational by
sending it echo frames and waiting to receive the same number
of frames in return.
Physical Layer Medium Dependent. The sublayer in the FDDI
architecture that specifies the optical fiber hardware
components that create the physical link between two adjacent
FDDI stations.
A point of access where a physical connection is made
between a device and cabling to another device, network, etc.
The FDDI standard defines four port types: A, B, M, and S.
Port type A (Primary IN/Secondary OUT) allows attachment
to the incoming primary ring and to the outgoing secondary
ring.
Port type B (Secondary IN/Primary OUT) allows attachment to
the outgoing primary ring and to the incoming secondary ring.
Port type M (Master) allows attachment between a
concentrator and a single-attach station. Uses the primary ring
only. See SAS.
Port type S (Slave) allows attachment between an SAS or SAC
and a concentrator. Uses the primary ring only.
Glossary
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