Transcript Chapter 7: Networking

Chapter 7: Networking
What is a computer network?
– A computer network is simply two or more
computers that are connected via software and
hardware so that they can communicate with each
other. You access networks all the time. When
you use an ATM, get gasoline, or use the internet
(the largest network), you are interacting with a
network.
What is a computer network?
– Each device connected to a network is referred to
as a node. A node can be a computer, a
peripheral (like a printer), a game console
(PlayStation or Xbox), a digital video recorder, or a
communications device.
What are the benefits of a network
– Most home users want a network to facilitate
resource sharing. A network allows you to share
the high speed internet connection coming into
your home. They also allow you to share printers.
What are the benefits of a network
– You can share files between networked computers
without having to use a flash drive. You can set
sharing options in Windows or OS X that allow the
user of each computer on the network to access
files stored on other computers on the network.
Are there disadvantages to setting up a
network?
Networks involve the purchase of additional equipment
to set them up, so cost is one disadvantage. Networks
need to be administered, at least to some degree.
Network administration involves tasks such as:
• 1. Installing new computers and devices,
• 2. monitoring the network to ensure it is performing
efficiently,
• 3. updating and installing new software on the network, and
• 4. Configuring proper security.
Fortunately, most home networks do not require a great
deal of administration after their initial configuration.
Network Architectures
– The term network architecture refers to the design
of a network. Network architectures are classified
according to the way in which they are controlled
and the distance between their nodes.
Network Architectures
– What different types of control do I have over my
network?
• Locally—local administration means that the configuration
and maintenance of the network must be performed on
each individual computer attached to the network.
– Peer-to-peer network is the most common example of a locally
administered network
• Centrally—central administration means that tasks can be
performed from one computer and affect the other
computers on the network.
– The most common type of centrally administered network is a
client/server network.
Network Architectures
• Peer-to-peer (P2P) network—each node
connected to the network can communicate
directly with every other node on the network.
Thus, all nodes on this type of network are
peers (equals).
Network Architectures
• Client/server networks—contains two
different types of computers: clients and
servers. A client is a computer on which users
accomplish specific tasks. The server is a
computer that provides information or
resources to the client computers on the
network. The server on a client/server
network also provides central administration
for network functions such as printing.
• When your computer is connected to the
internet, it is functioning as a client computer.
When it accesses the internet through an
internet service provider (ISP), your computer
connects to a server computer maintained by
the ISP. The server “serves up” resources to
your computer so that you can interact with
the Internet.
Describing networks based on distance
– How does the distance between nodes define a
network?
• A local area network (LAN) is a network in which the
nodes are located within a small geographic area.
This stands for Local Area Network and it is a network that is restricted to one
room, building or site. The cabling and hardware (infrastructure) that defines the
network are usually owned by the organisation. LANs allow users to share data
and peripherals like printers, often they are able to log on anywhere on the
network and access their own data from any computer. The network manager is
able to control access through the use of usernames and passwords and ensure
that data is kept secure and backups made.
Describing networks based on distance
• A home area network (HAN) is a network located in a
home. HANs are used to connect all of a home’s digital
devices, such as computers, peripherals, phones,
gaming devices, DVRs and televisions.
Describing networks based on distance
• Wide area network (WAN) is made up of LANs
connected over long distances. In a typical school the
computers that students and teachers use are set up in
a LAN. All of the schools in a district are connected via
a WAN.
– Are wireless networks that cover large areas like
cities considered WANs?
• Technically they are WANs, however, when a network is
designed to provide access to a specific geographic
area, such as an entire city, the network is usually called
a metropolitan area network (MAN).
This stands for Wide Area Network and is a network that uses some
form of external communications for computers to communicate
with each other. Some large companies, local authorities and
government departments operate WANs. Their regional and
district offices can be connected via leased lines and their
computers will all operate as if they were workstations on a LAN.
More common nowadays is for these organisations to use
telephone lines and run a web-based service or Intranet. By far the
biggest WAN in the world is the World Wide Web running the
Internet.
Network components
– To function, all networks must include
• A means of connecting the nodes on the network.
(cables or wireless technology)
• Special devices that allow the nodes to communicate
with each other and to send data
• Software that allows the network to run.
Types of cables
• Twisted-pair cable is made up of copper wires that are
twisted around each other and surrounded by a plastic
jacket. Normal telephone cable is a type of twisted-pair
cable.
• Coaxial cable consists of a single copper wire
surrounded by layers of plastic. If you have cable TV,
the cable running into your TV or cable box is most
likely coaxial.
• Fiber-optic cable is made up of plastic or class fivers
that transmit data at extremely fast speeds. Verizon’s
FiOS service uses fiber-optic cable to run very fast data
connections directly up to your home. (Inside the home
either twisted-pair cable or coaxial is used).
Tools and types of twisted pair
connectors
• Category 1—Used for telephone communications. Not suitable for
transmitting data.
• Category 2—Capable of transmitting data at speeds up to 4
megabits per second (Mbps).
• Category 3—Used in 10BASE-T networks. Can transmit data at
speeds up to 10 Mbps.
• Category 4—Used in Token Ring networks. Can transmit data at
speeds up to 16 Mbps.
• Category 5—Can transmit data at speeds up to 100 Mbps.
• Category 5e —Used in networks running at speeds up to 1000
Mbps (1 gigabit per second [Gbps]).
• Category 6—Typically, Category 6 cable consists of four pairs of 24
American Wire Gauge (AWG) copper wires. Category 6 cable is
currently the fastest standard for UTP.
$176.00
Coaxial cables
c.
Does it matter what type of media
you use to transfer data?
• Using wireless media is critical when portable
computing devices need to be connected to a network.
• Data transfer rate (also known as bandwidth) is the
maximum speed at which data can be transmitted
between two nodes on a network.
• Throughput is the actual speed of data transfer that is
achieved.
• Data transfer rate and throughput is usually measured
in megabits per second (Mbps). A megabit is 1 million
bits.