Hardware Reference
In-Depth Information
Hardware Elements of Your Network
The choice of a data-link protocol affects the network hardware you choose. Because the
various flavors of Ethernet and other data-link protocols use different hardware, you must
selectthearchitecturebeforeyoucanselectappropriatehardware,includingNICs,cables,
and switches.
NICs for Wired Ethernet Networks
On most computers, a wired Ethernet network adapter is integrated into the motherboard.
If the integrated component fails or is not fast enough, a replacement NIC can be
added through the PCI or PCI-Express slot (desktop computers), USB, CardBus PC Card
(PCMCIA), or ExpressCard slot on a laptop.
Network adapters (both wired and wireless) have unique hardware addresses coded into
their firmware. The hardware address is known as the
MAC address
. You can see the
MAC address on a label on the side of the adapter, or you can view it after the adapter is
installed with an OS utility such as the Windows
ipconfig.exe
command. The data-link
layer protocol uses these addresses to identify the other systems on the network. A pack-
et gets to the correct destination because its data-link layer protocol header contains the
hardware addresses of both the sending and receiving systems.
Most motherboards have wired Ethernet adapters built-in, whereas discrete Ethernet net-
work adapters range in price from less than $10 for client adapters to more than $100 for
single or multiport server-optimized adapters.
Although you can connect two computers directly to each other via their Ethernet ports
withacrossovercable,largernetworksneedaswitch,whichisfrequentlyincorporatedin-
toarouter.Thenetworkrunsatthespeedoftheslowestcomponent,soifyouuseaswitch
that runs at a slower speed than the network clients, the clients connected to that switch
will run at that slower speed. Many wireless routers now include 1000Mbps Gigabit Eth-
ernet ports instead of slower 100Mbps Fast Ethernet ports.
When connecting systems on wired Ethernet networks, the following sections contain my
recommendations on the features you need.
Speed
YourNICshouldrunatthemaximumspeedyouwantyournetworktosupport.MostGig-
abit Ethernet and Fast Ethernet cards also support slower speeds meaning, for example,
that a 1,000Mbps (Gigabit Ethernet) card also supports 100Mbps (Fast Ethernet) speed or
standard Ethernet's 10Mbps speed, allowing the same card to be used on both older and
newer portions of the network. To verify multispeed operation, look for network cards
