Specifications

A.1 Configuration Guidelines and Rules
FDDI Configuration Capabilities A–3
A.1.5 DEChub 900 Backplane
Technically, any type of configuration (dual ring, tree, or dual ring of trees) can be
created in the DEChub 900 backplane; however, for ease of use, only dual ring and
tree configurations are supported.
Up to four independent FDDI networks can be created across the DEChub 900 back-
plane. Each of the created FDDI networks can be either a dual ring or a tree on the
backplane, but not a mixture of both.
NOTE
A treed FDDI DEChub 900 backplane can connect to a dual ring that is
external to the DEChub 900, and can be part of an overall dual ring of trees
configuration.
A.1.6 Point-to-Point Connections
Note that any FDDI connection between two adjacent stations is actually two point-
to-point connections, regardless of where the stations are physically located in the
configuration (tree or dual ring). This is true for any FDDI product, whether the
product is in a hub or operating standalone.
The backplane of the DEChub 900 MultiSwitch is used to make point-to-point con-
nections between DEChub 900 FDDI network modules that are configured in the
hub. One backplane channel is needed for each point-to-point connection.
A.1.7 Backplane Channels
Because two point-to-point connections are required between any two ports, two
backplane channels are required for each connection between any two ports on the
DEChub 900 FDDI network modules, regardless of the actual configuration.