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LANs, WANs, MANs

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Intro
 Networks are categorized according to how
many locations they span.
 A network confined to a single location is
known as a LAN.
 Networks that span multiple geographic
locations are known as WANs.
 There is also another category, called a
MAN, which is used to classify networks
that fall somewhere between LANs and
WANs.

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LANs
 A LAN is confined to a single
geographic location, such as a single
building, office, or school.
 LANs are created with networking
media that are very fast but that can
cover a limited distance.

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WANs
 A WAN is a network that spans multiple
geographic locations. WANs are generally
slower than LANs and are considerably
more expensive to run.
 WANs are all about data throughput, and
the more need, the more you spend. WANs
connect LANs together to create an
internetwork.
 When Does a LAN Become a WAN?
 Technically, a LAN never becomes a WAN. Avoid
the temptation to refer to the entire
internetwork as a WAN because WANs and LANs
employ some very different technologies.

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MANs
 A MAN is confined to a certain geographic
area such as a university campus or a city.
 No formal guidelines dictate the differences
between a MAN and a WAN; technically, a
MAN is a WAN.
 Perhaps for this reason, the term MAN is
used less frequently than WAN. If any
distinction exists, it's that a MAN is smaller
than a WAN. A MAN is almost always bigger
than a LAN and usually smaller than or
equal to a WAN.

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Wireless Topologies
 The widespread interest in networks
without wires and the push toward
obtaining "anywhere, anytime" Internet
access has encouraged rapid growth in
wireless networking.
 Several wireless standards fall under the
IEEE-802.11 banner each with its own
speeds, radio frequencies, and transmission
ranges.
 The 802.11 wireless standards use two
main types of network topologies: the
infrastructure, or managed, wireless
topology and the ad-hoc, or unmanaged,

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Infrastructure Wireless Topology
 is commonly used to extend a wired
LAN to include wireless devices.
 Wireless devices communicate with
the wired LAN through a base station
known as an access point (AP) or
Wireless Access Point (WAP).
 In infrastructure wireless networks,
several access points may provide
wireless coverage for a large area.

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Ad-Hoc Wireless Networking
 In a wireless ad-hoc topology, devices communicate
directly between themselves without using an access
point.
 This peer-to-peer network design is commonly used
to connect a small number of computers or wireless
devices.
 For example, an ad-hoc wireless network may be set
up temporarily between laptops in a boardroom or to
connect to systems in a home instead of a wired
solution. The ad-hoc wireless design provides a quick
method to share files and resources between a small
number of systems.

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Wireless technologies
 802.11 (Frequency hopping spread
spectrum)
 802.11x (Direct sequence spread
spectrum)
 Infrared
 Bluetooth

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Infrared Wireless Networking
 Infrared wireless networking uses
infrared beams to send data
transmissions between devices.
Infrared wireless networking offers
higher transmission rates reaching
10Mbps to 16Mbps.
 The infrared light beams cannot
penetrate objects; therefore, the
signal is disrupted when something
blocks the light.

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IrDA Features
 Infrared devices use less power and a
decreased drain on batteries.
 Is a secure medium. Infrared signals are
typically a direct line implementation in a
short range and so do not travel far outside
the immediate connection.
 Has no radio frequency interference issues
or signal conflicts.
 Replaces cables for many devices such as
keyboards, mice, and other peripherals.
 Transmissions travel over short distances.

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Bluetooth
 Bluetooth is a wireless standard used for many purposes,
including connecting peripheral devices to a system.
 Bluetooth uses a low-cost, short-range radio link to
create a link to replace many of the cords that used to
connect devices.
 Bluetooth is an easily configured technology. When
Bluetooth-enabled devices are within 10 or so meters of
each other, they can establish a connection.
 Bluetooth establishes the link using an RF-based link and
therefore does not require a direct line-of-sight
connection. The Bluetooth Standard defines a short RF
link capable of voice or data transmission up to a
maximum capacity of 720Kb/s.