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Overview
The management module is based on the Motorola
provides the following:
This guide is intended for network installers and operators who are familiar with
FDDI technology and experienced in installing hubs. The next section contains
a brief summary of FDDI technology; it is intended as an overview only. (For
detailed information about FDDI architecture and its functionality, 3Com
recommends that you secure the FDDI self-paced study course, Understanding
FDDI, 3CS-360, available through 3Com Education Services.)
FDDI Technology
FDDI technology is an American National Standards Institute (ANSI) standard
that supports data transfer rates of 100 million bits per second (100 Mbps).
Advancements in fiber technology allow modulated beams of light to be carried
in dual counter-rotating token rings made of glass fiber-optic cable. The FDDI
standard now includes the definition of other types of cabling media, including
shielded twisted pair (STP) and unshielded twisted pair (UTP). FDDI provides
for up to 500 nodes operating over tens of kilometers. The maximum network
length is 100 km.
FDDI's dual-ring architecture provides a high level of reliability and fault
tolerance. Under normal operation one of the rings, called the primary ring or
the trunk ring, carries data traffic. The other ring, called the secondary ring, is
generally used for automatic recovery in the event of a break in the primary
ring. If a fault occurs, as shown in Figure 1-1, the dual attached stations on
either side of the fault detect and automatically bypass it. This ring
reconfiguration is known as a ring wrap.
256 KB of nonvolatile RAM
1 MB of local RAM
512 KB of EPROM
1 MB of flash memory
128 KB of RAM for frame buffer and descriptors
®
68EC020 processor, which
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