Sun Microsystems 1.0 - Manual (Page 169)

Glossary 143
LLC
(Logical Link Control). Local area network protocol functions corresponding to
the OSI data link layer (layer 2), but providing only service access points
(SAP).
MAC
(Media Access Control). Local area network protocol functions corresponding
to the OSI data link layer (layer 2), but providing the following: 1) on
transmission, assembles data into a frame with address and error-detection
fields; 2) on reception, disassembles frame, performs address recognition and
error detection; 3) links communications management.
Mbps
(millions of bits per second). A measure of the rate of data transmission. See also,
baud, bps, Bps, and kbps.
NRZI-4B/5B
(nonreturn to zero inverted). A differential encoding technique that encodes four-
bit data groups as five bits (data plus a signal element); satisfies the minimum
signal transition requirements to transmit synchronization (clock) within the
data stream.
OSI
(Open System Interconnection). The OSI model is a standard for computer-
communications protocols and the implementation of these protocols. The
model is a product of the International Standards Organization (ISO), and
specifies a seven-layer architecture with one or more protocol standards at each
layer.
PCM
(Physical Connection Management). The portion of CMT that manages a physical
connection between the PHY being managed and another PHY, likely in an
adjacent station on the FDDI network.
PHY
(Physical Layer Protocol). Performs the clock recovery and serial-to-parallel (on
receive) or parallel-to-serial (on transmit) of data between the transmission
medium and the MAC entity.
PMD
(physical medium dependent). Specifies the optical-to-electrical conversion
mechanism to conform to FDDI.