Telecommunications, P.II
AIMS 2710
R. Nakatsu
Telecommunications, P. II:
An Overview
Network technologies and concepts include:
Networking devices (switches, routers
repeaters, access points)
 Wireless networks

– Wi-Fi
– Cellular networks
Last mile broadband
 Internet/networking protocols
 Virtual Private Networks (VPNs)

Network Latency
Refers to the amount of time that it takes
a packet to get to its destination. It
represents the lag, or delay in
communications, between your computer
and another (target) computer.
 A ping test can be used to measure
latency.
 Having low latency (i.e. fast response)
is especially important where real time,
two-way communications are
required.
Networking Devices
are the hardware devices that unite the various
media and computers and route data and
communications throughout a network.
Three Examples:
1. NETWORK SWITCH – A device containing
multiple ports that enable you to connect computers,
printers, servers and other devices to a network. A
switch serves as a controller, enabling networked
devices to talk to each other efficiently within a local
network.
Network Switch: Central
Connection Point of a Network
Networking Devices, P. II
2. ROUTER – A networking device that connects two
or more networks: it routes packets of data from one
network to another.
 The router ensures that information doesn't go where
it's not needed.
 The router makes sure that information does make it
to the intended destination. Demo
Question: What is the difference between a router and a
switch?
3. REPEATER – a device that gives your network
signals a boost.
Wireless Networks: Wi-Fi
How do WiFi hot spots work?
–
Wireless network adapter
– Access points
1. A computer’s wireless network adaptor translates
data into a radio signal and transmits it.
2. The access point has an antenna that receives the
signal and decodes it. It sends the information to the
Internet using a cabled connection.
3. As a rule of thumb, the range is about 150 ft (indoors)
and 300 ft (outdoors)
The process also works in reverse (can send radio signals
to connected devices).
Wireless Networks: Cellular Networks

3G Cellular Networks offer access speeds usually
less than 2 MBPS (download). Two standards:
CDMA and GSM.
 4G Cellular Networks offer average speeds from 5
to 12 MBPS (download). LTE is the new global 4G
wireless standard.
SIM cards: What are these?
M-commerce (mobile-commerce)
– Widespread use of mobile devices (smartphones &
tablets) to buy and purchase over the Internet.
Square Demo
Benefits of Wireless Networks

They are comparatively cheaper to set up
than wired networks.
 Wired networks may require drilling through
walls and running cables through ceilings.
 A few well-placed wireless access points (or
building a mesh network) can reach far more
devices than a wired network.
 Obviously, you have more mobility using a
wireless network.
Question: Are there disadvantages of wireless
networks?
Wireless Mesh Networks
In a wireless mesh network, a network connection can be
spread across dozens or even hundreds of wireless mesh
nodes that “talk” to one another.
Each node is an access point with a radio transceiver.
Last Mile Broadband
When considering overall network speed remember
Amdahl’s Law: a system’s speed is determined
by its slowest component.
The bottleneck is the so-called last mile, or the
connection that customers use to get online.
Three types of last mile broadband:
1. DSL (digital subscriber line) uses the copper wire
the phone company has already installed.
2. Cable Broadband uses the cable network.
3. Fiber to the home (FTTH) is the fastest last mile
broadband (e.g., Verizon’s FiOS technology).
Internet/Networking Protocols
A protocol is a standard set of rules and
procedures for the control of communications
in a network.
Open Systems use common standards for
hardware, software, applications, and
networking.
Proprietary Systems are closed systems that
are owned and controlled by a single company.
What are some examples of each type?
The Great Debate of the Digital Age
Open vs. Closed (Proprietary)
Which is the better strategy?
Some Networking Protocols
Some Examples:
 Ethernet (LAN protocol): wired connections to a
network
 Transmission Control Protocol / Internet Protocol
(TCP/IP): Internet standard
Wireless Protocols:
 Bluetooth (low-cost wireless protocol with a range of
about 30 feet)
 Wi-Fi (standard for wireless computer networks—see
previous slide for more information)
 LTE (4G standard with larger range and higher data
speeds than 3G)
Public vs. Private Network
Public Network: a network on which your organization
competes for time and use with others.
Private Network: a network that your organization either
owns or exclusively leases the right to use the
communications media.
What are the benefits of public networks?
What are the benefits of private networks?
Virtual Private Network
(VPN)
A secure network that uses the Internet as its
main backbone network, but relies on firewalls
and other security features.
Example application: A VPN would enable a
company to use the Internet to establish secure
intranets between its distant branch offices and
manufacturing plants.
A Virtual Private Network
The
Internet
Router
Extranet
Fire wall
Intranet
Server
Fire wall
Router
Intranet
Server
Host System
Benefits of VPNs
• Extended connections across multiple
geographic locations (larger geographic
reach).
• Improved security for exchanging data.
• Savings in time and expense for employees if
they don’t have to come into the office to
work.
Setting up your own VPN
Popular VPNs include VyprVPN and
HotspotVPN
They encrypt all communications you transmit
wirelessly and over the Internet.
Some encrypt only web activity while others will
also encrypt email exchanges.