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Chapter 4:
Understanding Network Cabling
Has the contractor done any local installations that you can visit and view?
Does the contractor also provide speedy postinstallation support for new
wiring drops? This is important, as many wiring contractors who specialize
in new construction wiring are not good about returning to do the occasional
single drop for new node locations. Ask for references regarding this important
information.
What equipment does the contractor use to certify the cable plant? What
certification documentation will the contractor provide upon completion?
Does the contractor also provide postinstallation troubleshooting services?
Make sure to spend time finding the best local cable contractors available to you
and compare them carefully. You may want to contact other companies like yours, or
computer user group members in your area to seek recommendations and learn about
their experiences with contractors. Try not to rely on only the references provided by
the contractor; even firms that do sloppy work can usually put together a few good
references.
TIP
For a large cabling job, make sure to negotiate an appropriate payment schedule. You should
aim for something along the lines of 30 percent on inception; 50 percent on completion; and
20 percent on delivery of as-built drawings, certification reports, and any other final deliverables.
Make sure to keep no less than 15 percent for these final deliverables to ensure that the cable
contractor provides them expediently. Contractors are notorious for dragging their feet on things like
this after the wiring itself is done, so you need to make sure you have a way to motivate them to get
everything done.
Solving Cable Problems
Cable problems can be extremely hard to diagnose and repair. Many cable problems are
intermittent or result in reduced network bandwidth for the affected nodes. Tracking
down the source of the problem can be difficult. At times, you may not even be aware
that there is a problem with the cables!
Problems with network cabling typically exhibit themselves in the following ways:
Abnormally slow network performance, particularly if one node is much
slower than other, similar nodes (for star networks) or if all nodes on one
segment have slower network performance than nodes on other segments (for
bus networks)
Sporadic disconnections from the network
Complete loss of network connectivity, which can also be an intermittent
problem