3Com CoreBuilder 3500, Руководство по внедрению

Страница: 101 / 592

Key Guidelines for Implementation 101
Ports 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.
Each port is one of four types: A, B, M, and S.
■
A port — Connects to the primary ring on the incoming fiber and the
secondary ring on the outgoing fiber. A properly formed FDDI dual
ring is composed of a set of stations with the A port of one station
connected to the B port of the neighboring station.
■
B port — Connects to the incoming fiber of the secondary ring and
the outgoing fiber of the primary ring.
■
M port — Used by a concentrator station to provide connections
within a concentrator tree. Also referred to as Master port .
■
S port — Used by a single attachment station to provide attachment
to an M port within a concentrator tree. Also referred to as Slave port .
Key Guidelines for
Implementation
Consider the following guidelines when you configure and implement
FDDI in your system:
■
A high frame error rate often indicates a faulty station on the FDDI
ring or a dirty FDDI connector or cable.
■
If there is something wrong on your network, you may want to turn
off data (user) traffic for a MAC by disabling LLC service. Although
you have disabled data traffic from the MAC, the MAC still
participates in neighbor notification and is visible to network
management.
■
The FDDI MAC path selections depend on the stationMode
configuration (DAS or SAS).
■
FDDI ports can be type A or type B for DAS ports.
■
FDDI ports can be type S or type M for SAS ports.