Cabletron Systems MMAC-5FNB, Сетевое руководство

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Workgroup Creation 4-7
Network Design
Priority organization of this manner in a single-segment network involves
providing stations in the priority workgroups with qualities of media and
network connection based on that priority. The stations in the server farm, to
continue with that example, might have redundant connections to the network in
the event that one cable failed, or might utilize a media that is resistant to
interference, such as fiber optic cabling, or might be best served by a centralized
location. A priority organization workgroup or sub-section of a workgroup which
is located on the same network segment as its most common users is usually an
efficient and safe use of resources, and will not impede the operation of the
network.
While keeping the users separate from the devices they need to access on a
regular basis does enhance the Network Manager’s control over its use and
operation, it does reduce network performance in networks utilizing
segmentation. The priority organization method, by connecting stations to the
network based on their relative importance, makes little or no accommodation for
the localization of network traffic which is the purpose of segmentation. If a file
server is located in the server farm workgroup, which is segmented from the rest
of the network, every user needing access to any file server must cross a
segmenting device such as a bridge or switch, which introduces access delays as
the device reads in the packet, examines the packet, determines whether to send it
on or discard it, checks the packet for errors, and acts on its forward or discard
decision. The necessity of crossing the segmenting device on a regular basis
destroys the network availability that is gained by bridging, as local traffic is no
longer kept local.
The use of priority organization also introduces additional troubleshooting
complications. If a station in the Sales department cannot access their file server, is
it because the server has failed, the bridge connecting the server to that
department is in error, the connection from the Sales department to the bridge is
down, or the connection from the employee’s workstation to the rest of the Sales
workgroup is faulty?
Selecting Workgroup Organization
Once the rules for the creation of workgroups have been cemented and the
Network Manager has determined which end user stations will be members of
which workgroups, the issue of how the workgroups will relate to one another
must be addressed. These relations determine the network equipment required
for the network to operate and for the workgroups to communicate with one
another.
Workgroups can be all grouped together into a single network or separated from
one another by various means. In networks with relatively light network
demands (few users, long periods of light traffic, etc.) a single, unsegmented
network will often provide faster responses than a segmented network of the
same technology. As user counts and network traffic increase, however, the
utilization of segmentation becomes more and more important.