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when upgrading an existing network, and one of the
most satisfying when working on a Greenfield project.
From a Greenfield perspective, one needs a list of de-
vices (or expected devices) on the network, how these
devices will be segregated (VLAN assignments), and
any restrictions on what ranges can be utilised (some-
time ranges may be assigned on a site-by-site basis, for
instance). Once all this information has been gathered
it becomes a simple matter of subnetting IP ranges to
break them down into smaller groups, which should
then cater for the number of devices in each VLAN. With
the free tools available online it becomes a straightfor-
ward task. IPs are then assigned to the actual devices
and all the assignments are documented. It is necessary
to add a bunch of devices to an existing network, things
can become more complicated, depending on how well
the original design catered for expansion. In a best case
scenario no extra VLANs (and thus IP ranges) are need-
ed and all existing ranges have open IP addresses for
each new device to be added. In many cases however,
the existing ranges are too small for the expansion re-
quired. This is where things can become painful. Some-
times it will suffice to make small changes to existing
subnet masks to include other devices, as long as this
does not overlap with existing ranges. In other cases,
redesign of the IP structuring for the network, and reas-
signment of all existing IP addresses to cater for the new
design, will be required. Furthermore this will involve
large amounts of reconfiguration of existing devices on
the network to accommodate the new structure. Finally,