3Com LINKBUILDER 3C18500, User Manual

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Token Rings within the MSH Chassis 9 - 5
DUA1850-0AAA05
The management module enables you to configure and monitor the
operation of the RingBuilders, MAUs and any other manageable
devices, for instance bridges.
LinkBuilder MSH token ring products feature switches to select ring
speed (4Mbps or 16Mbps). The ring speed selection cannot be
overridden by management command: it can only be reported using
VT100 management (see Chapter 11 ) or a network management
station.
MSH RingBuilder
Each RingBuilder is assigned a “Local Ring Section Number”, which is
unique within the MSH chassis. The local ring section number is initially
set by switches on the module, but can be overridden by management
command (see “ Facility Table ” on page 11-20 ).
Other modules, for example MAUs, also have local ring section
numbers assigned, to indicate the particular ring section into which
they need to be connected. Some modules, for example bridges, will
connect into several local ring sections each controlled by a different
RingBuilder.
The function of the RingBuilder is to search the chassis for modules
which have a local ring section number that match that assigned to the
RingBuilder, and to create a single ring from those modules.
The RingBuilder provides external connections through its Ring-In and
Ring-Out ports, so that the local ring section it has created can be
connected to other ring sections constructed by other devices. For
more details see “ Extending the Local Ring Section ” on page 9-15 .
When connected, these local ring sections form a single token ring.
If no MAUs share the same local ring section number as the
RingBuilder, the RingBuilder will simply connect to an external token
ring through its Ring-In and Ring-Out ports.
The RingBuilder module provides retiming to its local ring section and
to the Main Ring and Backup Ring; consequently the RingBuilder
module is equivalent to 3 station counts. This retiming removes the