Why Bother to Design Your SME Network?
A good question: most people don't. Most people browse over to their online networking
accessories supperstore, cdw.com, buy a kit, plug it in and off they go.
Usually it works just fine, so why bother to design your network?
The answer lies in the following main areas:
Function and performance: For a single PC with directly attached peripherals
and no sophisticated requirements, an ad-hoc installation will probably be adequate, but as
soon as you start to use multiple PCs or remotely-connected peripherals (such as networked
printers) then function and performance become important.
You have to know what load your systems are imposing on the network, which bits might
interfere with which other bits and what's likely to happen if something breaks. If you're a
business, then designing your network to optimise for function and performance can make the
difference between a business that struggles with its computer systems and one that doesn't
notice them because they work flawlessly.
Security: This term covers a wide variety of issues, such as making sure that:
• your private data stays private.
• your employees⁄children⁄pets can only access what you want them to access.
• your data is not destroyed nor your network rendered unusable by the failure of a single device or component.
• "finger trouble" by one of your users cannot corrupt vital data.
• you comply with legal requirements.
Flexibility: again, for a single computer, flexibility is probably not an issue,
but what about when you buy a laptop for the kids, your smart meter or burglar alarm needs
to access the Internet using your ADSL connection, you need to access your home data from your
work computer or your mobileFrasl;PDA? Or what about that whizzy function no-one has even thought
of yet? A little time spent considering the potential future development of your network will
repay itself many times over with reduced expense and grief when you find that you have to
throw away bits of your ad-hoc network because they don't support the functions you want to add.
OK, so I want to design my home⁄SME network. Where do I start?
Difficult... Or maybe not. That future unknown functionality might cause a problem, mightn't
it? Well, possibly but probably not. In the "good old days" networks were proprietary and incompatible,
but in the last half-century lots of people have put in lots of effort to devise standards.
Some of these may look a bit quaint and awkward, but, generally, the key ones are adhered to,
so future developments should fall within these standards.
For small networks, the key ones are the transport mechanisms (Ethernet (IEEE802.3) for
cabled connections and Wi-Fi (IEEE802.11) for wireless), and the transmission protocols (primarily
TCP-IP). Of course, there are others, but lets keep it simple for now.
But aren't these what all the available kit conforms to?
Well, in theory. However, there are subdivisions within these standards (such as transmission
speeds for Ethernet of 10Mbps, 100Mbps and 1Gbps) and not all the kit supports all these subdivisions.
For instance, an old PC may have a 10Mbps network card. This will not work with a switch that
only supports 100Mbps Ethernet.
Similarly for the transmission mechanisms: Most kit nowadays uses UTP (Unshielded Twisted Pair)
cable with RJ-45 (technically "8P8C") connectors and what is known as "Category 5" (or '5e' or '6') cable.
Old installations may use older category 3 or even non-standard cables (and some very old kit may
use co-axial or screened cables to the 10base2 or 10base5 standards). While these may work with
10Mbps connections, they will probably fail if you try to use them for 100Mbps traffic, and the faults
can be very obscure and hard to trace. Hence, especially if you are re-using old kit, you MUST know
what standards it supports.