3Com LANPLEX 2500, Руководство по эксплуатации

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Ports 9-3
Figure 9-1 FDDI Relationship to OSI Reference Model
Ports
As parts of the Physical Layer, the PHY and PMD entities work together to
support each link between FDDI stations. These entities provide the
protocols that support the transmission and reception of signals between
stations, as well as the optical fiber hardware components that link FDDI
stations together. Within an FDDI station, the PHY and PMD entities make
up a
port . Together, they create a PHY/PMD pair that connects to the fiber
media and that provides one end of a physical connection with another
station.
Ports located at both ends of a physical connection determine the
characteristics of that physical connection. The protocols that are executed
at each port determine whether the connection is accepted or rejected. A
connection is accepted if at least one station’s policy allows such a
connection. A connection is rejected if each station has a policy that
disallows the connection.
Application Layer
Presentation Layer
Session Layer
Transport Layer
Network Layer
Data-Link Layer
Physical Layer
LLC
MAC
PHY
PMD
SMT
(Logical Link Control) — IEEE 802.2
FDDI