- Many kinds of nodes can be connected to the hub
with networking cable.
- All hubs can be uplinked together, either with
straight-through cable or cross-over cable, depending on whether
or not the hub has an uplink port.
- Performance will decrease as the number of users
is increased.
When choosing a hub, the main consideration should
be performance. If the hub is 100Mbps and there are five users, each
user will receive only 20Mbps of bandwidth. If the hub is intended for
a small network with very little traffic, this should not be a problem.
However, if the network is large or expected to expand, a switch is
a better option in the end.
When considering a hub, always remember that the network
may expand in the future. Try to buy a hub that has enough ports to
allow expansion without more hardware purchases. If expansion is not
an immediate concern, remember that in the future you can add more hubs.
The
standard hub is great for starting a small network, or providing a network
to one department. There are two basic types: 10baseT, which will support
a speed of 10Mbps; and 100baseTX, which supports 100Mbps. A standard
10baseT hub cannot connect to hardware that runs at 100Mbps unless a
switch or hub with auto-sensing capabilities is used between them. If
your network is small and will not require expansion in the near future,
a standard hub is the perfect solution.
Many hubs have one or more of the following extra
features, which can increase ease of use, efficiency, and expandability:
- Auto-sensing or dual-speed 10/100Mbps. Hubs with
this feature can support hardware running at both speeds, increasing
the length of time you can use your old 10baseT hardware.
- Stackable hubs. Hubs with this feature are very
expandable, operating as a single hub when stacked together. While
standard hubs can only be uplinked through four hubs, a stacked
hub is considered a single hub and there is no uplinking required.
- SNMP (Simple Network Management Protocol). Hubs
that support SNMP allow configuration of the hub from anywhere on
the network. This feature can be extremely useful in LANs that span
two or more floors, or have more than 50 users.
Final note on hubs: Always remember that hubs can
only communicate in half duplex mode, which means that a computer on
the network can only send data when it is not receiving. If the network
requires full duplex mode, use a switch rather than a hub.
Ethernet Switches
Switches
have many features that make them different than hubs. The most compelling
reason to choose a switch rather than a hub is bandwidth. When a 100Mbps
hub has five workstations, each receives 20Mbps of bandwidth. When a
10/100Mbps switch is used, each workstation receives 100Mbps of bandwidth,
dramatically increasing the speed of the connection. Switches also run
in full duplex mode, which allows data to be sent and received across
the network at the same time. Switches effectively double the speed
of the network when compared to hubs, which only support half duplex
mode.
A 10/100Mbps switch can also
support hardware running at either 10Mbps or 100Mbps, allowing the continued
use of older technology and delaying replacement.
Switches will increase the speed
and efficiency of networks in any of the following situations:
- Any network that calls for a 10/100 hub will
benefit from a 10/100Mbps switch. The switch will increase available
bandwidth, drastically increasing the speed that the network is
running at.
- Any network that requires enhanced performance
for file servers, workstations, Web servers, etc. Any critical components
should be connected directly to a 10/100Mbps switch.
- Any network that uses high-speed applications
including multimedia and video. Any workstation or file server using
the intensive applications should be connected directly to a 10/100Mbps
switch.
- Any network that uses Fiber optic cabling should
use a 10/100Mbps switch rather than a hub. A hub will not take full
advantage of the speed possible with Fiber optic cabling.
Summary
The main difference
between hubs and switches is the bandwidth available to network users.
If your network consists of very
few nodes, a hub may be the best way to go. However, always keep in
mind future expansion of the network. If bandwidth could become an issue
among the users of the network, using a switch will increase the efficiency
of the network.
Remember that you do not necessarily
have to choose between hubs and switches. Your network may benefit most
from a combination of the two, with critical components directly connected
to the switch, and non-critical components on a hub connected to the
switch.
Hubs
form the heart of a network, with every separate node of the network
connected to the hub through its ports. Anything from a file server
to a workstation to a print server can be connected to the hub, making
it accessible to every other node of the network.
