3Com LINKBUILDER 3C18500, User Manual

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DUA1850-0AAA05
need for complex calculations required to establish maximum lobe
lengths (see “ Cable Lengths ” on page 9-21 ).
A maximum of five RingBuilders may operate within the same MSH
chassis.
An additional function of a Ring Builder is Distributed Recovery
Intelligence (DRI). DRI allows a faulty station to be isolated from the
ring. If a station starts beaconing due to a hardware fault, DRI will
remove the station from the ring by disabling the port to which it is
attached. DRI can be enabled with or without lock, or disabled using
VT100 management.
Enabled The port with the faulty station attached is disabled until
that station is removed physically from the ring. The port will then
be re-enabled.
Enabled with lock The port with the faulty station attached is
disabled and will remain so after the station is removed from the
ring. Management from the VT100 interface can re-enable the port.
Figure 9-4 shows two RingBuilders within an MSH chassis:
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RingBuilder1 has its Ring-In and Ring-Out ports connected to an
external ring using external trunk cabling. No MAUs are configured in
its local ring section. The external ring consists of the Main Ring and a
Backup Ring. The dual ring provides ring resilience and enables the ring
to wrap, rather than fragment when a cable break occurs.
To determine the state of the Backup Ring, you will need to install MAC2
on the RingBuilder (see “ MAC and MAC Addresses ” on page 9-7 ).
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RingBuilder2 connects several MAUs to form an internal local ring
section.