Hardware Reference
In-Depth Information
Ethernet ports.
When connecting systems on wired Ethernet networks, the following sections contain my
recommendations on the features you need.
Speed
Your NIC should run at the maximum speed you want your network to support. Most Gigabit 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 identified as 10/100 or 10/100/1000 Ethernet. All
modern Fast or Gigabit NICs should also support full-duplex operation:
• Half-duplex means that the network card can only send or only receive data in a single
operation.
• Full-duplex means that the network card can both receive and send simultaneously. Full-duplex
options boost network speed if switches are used in place of hubs. For example, 1,000Mbps
Gigabit Ethernet cards running in full-duplex mode have a maximum true throughput of
2,000Mbps, with half going in each direction.
Note
Unlike hubs, which broadcast data packets to all computers connected to them, switches create
a direct connection between the sending and receiving computers. Therefore, switches provide
faster performance than hubs; most switches also support full-duplex operation, doubling the
rated speed of the network when full-duplex network cards are used.
For more information about switches, see the section, “
Switches for Ethernet Networks
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Bus Type
If you need to install a network adapter for use with a Gigabit Ethernet (10/100/1000Mbps) network,
any of the following buses have more than adequate performance:
• PCI/PCIe—The integrated NIC built into most motherboards are either PCI or PCIe devices.
• CardBus/ExpressCard (laptop computers).
All these buses support Gigabit Ethernet adapters without limiting throughput. Integrated network
adapters use either the PCI or PCI Express bus to connect to the system, both of which have more than
enough bandwidth. Note that USB 2.0 (480Mbps) is not on that list because it is simply not fast
enough to fully support Gigabit Ethernet's 1,000Mbps bandwidth; however, 100Mbps Ethernet
connections will work on USB 2.0 with no problems. USB 3.0 (5Gbps) is more than fast enough to
support a Gigabit Ethernet adapter, and a number of vendors now provide USB 3.0 adapters for
Gigabit Ethernet networks.
Wired Network Adapter Connectors
Wired Ethernet adapters typically have an eight position, eight conductor (8P8C) connector
informally known as an RJ-45 connector, which looks like a large telephone jack. Fast Ethernet and
Gigabit Ethernet twisted-pair cables use these connectors, but you might still see older adapters that
support a single BNC connector (for Thinnet coaxial cables) or a D-shaped 15-pin connector called a
