Table 2-3.—Types of backbone cable.
Connection to the backbone network may require a
bridge, router, gateway, concentrator or hub, depending
on the architectures of the various LANs and the
backbone itself. The connectors used will also depend
on the type of cable used for the backbone. If the
backbone is coaxial cable, you would use a T-connector
and barrel connectors to make the connection to another
cable or a hardware device.
The backbone manages the bulk of the traffic, and it
may connect several different locations, buildings, and
even smaller networks. The backbone often uses a
higher-speed protocol than the individual local area
network (LAN) segments.
One obstacle to a successful backbone network is
the high bandwidth that may be required to handle
potentially heavy traffic. Because of this consideration,
fiber-optic cable is the most sensible cabling for
backbone networks.
NODES
The computers, or nodes, in a network may be used
for workstations, servers, or both. PCs need a network
interface card (NIC) installed for networking
capabilities.
The NICs mediate between the computer and the
network by doing the necessary processing and
translation to enable users to send or receive commands
and data over the network. NICs are designed to
support a particular network architecture, such as
Ethernet® or ARCnet®.
To connect a node directly to a backbone, you
would use a drop cable for the connection. Nodes are
normally connected to the backbone indirectly through
a concentrator or a hub rather than with a drop cable.
The elements needed to connect a node to a network
include the following:
e
l
l
l
Cable: twisted-pair, coaxial, or fiber-optic
Wiring centers: hubs or concentrators
Intranetwork links: connectors, repeaters, and so
on
Internetwork links: bridges, routers, gateways,
and so on
The cable provides a transmission medium, as well
as the physical link between the nodes on the network.
Connectors and repeaters attach cable sections to each
other; connectors and transceivers attach NICs to a
cable and, thereby, to the network. Transceivers enable
different types of cable to be attached to each other.
Terminators absorb a transmission at the end of a
network, preventing the signal from traveling back in
the other direction on the network. The types of
intranetwork links allowed in the network depend on
the type of cable used and on the network topology
used.
Wiring centers serve as a focal point for network
elements, and may influence the logical arrangement of
nodes on the network.
Internetwork links may be bridges, routers,
gateways, and soon. Such components serve to connect
networks to each other. The type of internetwork link
depends on whether the two networks are the same or
not, and the amount of translation that is needed.
NETWORK SERVER
A server is the central computer in a network, and is
responsible for managing the network. The server
provides some type of network service. It may be
hardware, such as a file server, or software, such as
network level protocol for a transport level client.
The server provides its service to other
workstations on the network or to other processes. In a
server-based network, the most important hardware
server is the fileserver, which controls access to the files
and data stored on one or more hard disks.
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