Installing and Administering HP EISA FDDI/9000 and HP HSC FDDI/9000

101
Glossary
P
packet Data information that is
grouped and transmitted together,
such as messages, commands, and
control codes.
PCM (Physical Connection
Management) That portion of the
Connection Management (CMT)
within the Station Management
(SMT) function of an FDDI station
that manages the physical connect
between adjacent PHYs. This
includes the signaling of the
connection type, link confidence
testing, and the enforcement of
connection rules.
peer-to-peer Assigning of
communications tasks so that data
transmission between logical
groups or layers in a network
architecture is accomplished
between entities in the same
sublayer of the OSI model.
PDU (Protocol Data Unit) The
unit of data transfer between peer
layer entities. It may contain control
information, address information,
and/or data (for example, a Service
Data Unit from a higher layer
entity). A valid PDU is at least 24
bits in length. The FDDI MAC
PDUs are tokens and frames.
PHY (Physical Layer Protocol)
A standard protocol that defines
symbols, line states, clocking
requirements, and the encoding of
data for transmission.
Physical layer Layer 1 in the OSI
model; defines and handles the
electrical and physical connections
between systems. The physical layer
can also encode data into a form that
is compatible with the medium
(coaxial, twisted pair, fiber, and so
on).
PING (Packet Internet
Groper) A TCP/IP protocol
facility used to test the reachability
of destinations by sending an ICMP
(Internet Control Message Protocol)
echo request and waiting for a reply.
PMD (Physical Layer Medium
Dependent) A standard that
defines the medium and protocols to
transfer symbols between PHYs.