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When you purchase and install a switch you should review and apply the following
criteria.
- Your switches must be compatible with your physical and data link level
protocols. If you are running a 10BaseT Ethernet network, then you must
purchase a 10BaseT switch.
- Some switches can accommodate more than one physical or data- link level
protocol. For example, modern switches accommodate both 10BaseT and
100BaseTX protocols It is wise to purchase a switch with at least one
100BaseTX port, since you can interconnect your switches via their high-speed
ports to improve network performance (even if the remainder of your network
uses 10BaseT).
- If you purchase a switch that accommodates more than one protocol, then make
sure that it automatically senses which protocol is being used on each port.
Auto-sensing switches ensure that you can connect any part of the network to
any switch port. (Older switches required you to attach each segment of the
network to a port compatible with its physical and data-link level protocol.
Keeping the segments and ports straight presents a management challenge.)
- Purchase switches from a known manufacturer whose support you trust. Make
sure that the manufacturer provides a competitive warranty.
- If possible, install your switches in a room that is cool and free of dust.
Additionally, plug your switches into an uninterruptible power supply (UPS) to
ensure that they receive clean power.
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When you purchase a hub you may wish to keep the following information in mind.
- Like switches, your hubs must be compatible with your physical and data-link level
protocols. If you are running a 10BaseT Ethernet network, you must purchase
10BaseT hubs. Some hubs, called multiprotocol hubs, can accommodate more than
one physical and data-link level protocol. If you purchase a multiprotocol hub, make
sure that it automatically senses which protocol is being used on each port. Auto-
sensing hubs ensure that you can connect any part of the network to any hub port.
(Older hubs required you to attach each segment of the network to a port compatible
with its physical and data-link level protocol. Keeping the segments and ports
straight presents a management challenge.)
- Make sure that your hub includes an AUI port (connector). (AUI is an abbreviation for
attachment unit interface.) AUI ports are intended to connect with a kind of cabling
called thick coaxial cable (like that used for cable TV). While this cable is no longer
often used for Ethernet networks, AUI ports are versatile in the sense that they can
be fitted with adapters to connect to many different kinds of cable (for example, thin
coaxial cable or fibre).
- Also make sure that your hub includes a crossover port. Unlike regular hub ports,
which connect hubs to clients, servers or peripherals, a crossover port connects
one hub to another. Some hubs can be stacked. Stackable hubs look like one giant
hub to the network. That is to say, the Ethernet restriction on the number of hubs that
can be traversed in a single network does not apply to stacked hubs
- Purchase hubs from a known manufacturer whose support you trust. Make sure the
manufacturer provides a competitive warranty.
- If possible, install your hubs in a room that is cool and free of dust. Additionally, plug
your hubs into an uninterruptible power supply (UPS) to ensure that they receive
clean power.
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When you purchase and install a router (ap3069g.htm), you may wish
to keep the
following points in mind.
- It is best to purchase all your routers from a single manufacturer. Purchasing routers
from a single manufacturer ensures that the software you use to configure and
manage the routers via the network will be compatible across devices.
(ap3096g.htm) It is very important to be able to monitor and manage routers across
the network if you want to keep things running smoothly. Make sure that your router
manufacturer offers a wide variety of routers, including models for local area
networks, dial-up connections, and wide area networks so that you can continue to
purchase from the same manufacturer as your network grows. Consult other
schools to see which router manufacturers they have used and liked.
- Before you purchase a router, you should draw a picture of your network, including
the place where you intend to put the router. Then label the segments on either side
of the router with the kind of cable used as well as with the protocols that will travel
across the router to and from each segment. Your router must accommodate the
cable types on all adjacent segments. In addition, the router must be compatible with
protocols that appear on both sides of the router.
- Before installing a router, choose the router model(s) that you need. Document the
protocols in use, the kind of information that will be exchanged on the attached
network, the kinds of information that may be restricted, the number of users and
their patterns of usage. Match the router's capabilities to your particular network
needs.
- Routers are often expensive. Your router should be easily upgraded so that you need
not replace the entire device as your network incorporates additional kinds of cable
or protocols. Ask manufacturers about the particular expansion modules they offer,
and what is involved in purchasing, installing, and maintaining them.
- If your school plans to deliver multimedia applications over the internet, choose a
router that is capable of providing QoS (quality of service) services. Multimedia
applications require a fast, steady stream of data to function properly. To deliver this
increased performance, internet standards organisations have defined options that
allow routers and other network devices to reserve the bandwidth they need on the
internet. Such equipment assuresQoS, for specified purposes. If you are planning for
multimedia delivery over the internet, you may wish to make sure that your router
does so.
- Price should not be the determining factor in purchasing a router. Routers, like
servers, are key components of your network. It is far better to purchase reliable
equipment from recognised manufacturers than to suffer equipment breakdowns or
malfunctions.
- Like switches and hubs, routers need to be installed in a room that is cool and free of
dust. Additionally, plug your routers into an uninterruptible power supply (UPS) to
ensure that they receive clean power.
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