Ethernet

6-24 Ethernet Workgroup Design

Permutations
It is also possible to use an Ethernet switch to connect a series of individual
workgroups, rather than workstations or other devices. In these situations, the
Ethernet switch acts as a device collapsed backbone for the network. The design
process is exactly the same as that used to connect multiple workstations over an
Ethernet switch, but the connections are made to workgroups rather than
individual stations.
Design Example
Our example situation for the interconnection of workgroups through a
standalone Ethernet switch involves a planned device collapsed backbone. This
backbone will be implemented in a small vocational college which plans to
interconnect its Ethernet classrooms and laboratories. The classrooms and labs are
configured with Ethernet stackable hubs. There are four classrooms and two labs
to be connected to the backbone, and there is expected to be growth in the number
of Ethernet workgroups at the college in the future. The connections from the
classrooms to the switch (which will be located in one of the labs) will have to be
made through an aerial cable between buildings. Since conductive cable run
between buildings is a lightning hazard, multimode fiber optics will be used to
connect to each stack.
The Network Designer examines the available Ethernet switches for a product
with sufficient management, port count, media, and interface characteristics. The
only Ethernet switch in the selection field that provides native multimode fiber
optic media support is the ESX-1380, which provides sufficient numbers of ports
and the availability of a BRIM port for future migration to new networking
technologies. The Network Designer plans on using the ESX-1380 and orders six
EPIM-F2s which will provide multimode fiber optic connections at each of the six
remote workgroups.