Cabletron Systems Cabletron BRIM-F6, Networking Manual

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Token Ring
8-4 Token Ring Workgroup Design
Media
It is assumed by this document that the selection of a networking media for the
facility has already been completed before the hardware is examined. The media
decision in the hardware selection stage of network design is one of ensuring that
the selected device or devices will support the cabling media that is either
planned or in place.
In some cases, a small number of station connections will have to be made using a
less common media such as fiber optic cable. For these situations, Cabletron
Systems produces a wide variety of media converters, which act as transceivers,
allowing a Token Ring link to be made through two dissimilar media.
Cabletron Systems also provides Token Ring Port Interface Module, or TPIM slots
on all of its standalone and stackable Token Ring networking devices. These TPIM
slots can be used as Ring-In/Ring-Out ports for the extension of the Token Ring
network (discussed below) or used as individual station connections to devices
requiring custom media links.
Port Count
The provision of a sufficient number of ports is perhaps the easiest and most
straightforward portion of the Token Ring network design process. As all of the
Cabletron Systems standalone Token Ring networking products are also stackable
devices, any time a particular location requires more ports than can be supplied
by one device, an STH stackable Token Ring hub can be placed atop it. This new
device will provide the same management capabilities as the base device, and a
greater number of available ports.
This stacking process can be continued until either the maximum number of
stations on the ring has been reached, or until a single stack incorporates one
stackable base device and four stackable hubs. The limitations of the stackable
system will not allow more than five devices to be associated with one another in
a single stack.
Should the port count supplied by a maximum-size stack not be enough to
accommodate the user count of an installation, the network will have to be
extended, using Ring-In/Ring-Out ports.
Ring Extensions
Ring extension allows for the growth of a Token Ring network beyond the
limitations of a single stack. The use of Ring-In/Ring-Out (RI/RO) ports allows
extended lengths of cabling to be used to connect stacks or standalone devices.
NOTE
RI/RO ports do not provide segmentation functions or create a
new Token Ring network.