Telecommunications, P.II

AIMS 2710AIMS 2710R. NakatsuR. Nakatsu

Telecommunications, P. II: An Overview

Wireless networks– Cellular networks– m-commerce

Networking protocol– Open vs. Proprietary Systems

History of the Internet (Origins and Evolution) How does the Internet work (TCP/IP)

– IP: What is an IP address? Types of IP addresses.– TCP: How is data sent over the Internet?

Virtual Private Networks (VPNs): Three types

Access Point (Wi-Fi) Standards

Routers that you purchase for home use typically provide multiple functionality. They can act as a router, access point, and switch. If used as a pair, one can be set to “repeater mode” to extend the range of the wireless network.

Wireless Networks: Cellular Networks3G Cellular Networks have two standards: CDMA and GSM.4G Cellular Networks allow you to download data up to ten times faster than 3G. LTE is the emerging 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 Trying on glasses

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 Interference

Interference is anything disrupting the path of a signal.

What are some examples of wireless interference?

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.

Networking protocols tend to be open systems.

What are some examples of each type?

The Great Debate of the Digital Age

Open vs. Proprietary (Closed)

Which is the better strategy (from the consumer’s perspective)?

Some Popular Networking Protocols

Some Examples: Transmission Control Protocol / Internet Protocol (TCP/IP): Internet standard; really a “suite” of protocols. Ethernet (LAN protocol): wired connections to a network

Wireless Protocols: Bluetooth (low-cost wireless protocol with a shorter range than Wi-Fi) Wi-Fi (standard for wireless computer networks; requires that you be within range of a wireless access point) LTE (4G standard with larger range and higher data speeds than 3G)

History Of The Internet: OriginsThe Internet has its roots in the U.S. military,

which funded a network in 1969 called ARPANET. Computers at colleges and universities were interconnected.

Web did not exist Largely a linear text-based medium Little interactivity

History Of The Internet: Evolution In the late 1980’s ISP (Internet Service

Providers) began offering dial-up Internet accounts for a monthly fee, giving users access to email, discussion groups, and file transfers.

In 1989, the World Wide Web was born. By the early 1990s the combination of email, the

Web, and interactive services such as online chat propelled the Internet to international prominence.

Today, Web 2.0 sites offer increased interactivity (social media, blogging)

IPv4An IP Address uniquely identifies a device

connected to the Internet. It allows each device to send and receive information.

IP addresses are usually displayed as a string of four numbers between 0 and 255, separated by three periods. Examples:

17.255.64.123192.168.1.1

Solutions to the Limitation of IPv4IPv4 allows for 232 unique IP addresses—

about 4.3 billionWe do not have enough IP addresses. What

are some solutions to the shortage?

1. IPv6: IP addresses are 128-bit, which will allow for unlimited IP addresses.

2. Dynamic IP addresses (see next slide)3. Private IP addresses (see next slide)

Static vs. Dynamic IP AddressesStatic IP addresses never change. Web servers and

other computers that need a consistent point of contact require a static IP address.

Dynamic IP addresses are temporary. Internet Service Providers (ISPs) have a pool of IP addresses that are shared and reused among computing devices.

The DNS (Domain Name System) maps a web address (e.g. www.lmu.edu) to a static IP address (157.242.196.198)

Go to whatismypublicip.com to get more information about your IP address.

Public vs. Private IP AddressesPublic IP addresses are used on the outside of

your network. It’s the main address that the home or business uses to communicate with the Internet.

Private IP addresses are used "inside" a network, like the one you probably run at home.

How is data sent over the Internet? Packet-switching: information is broken into

smaller segments called packets by TCP/IP; addressing information is attached to each packet. The packets are reassembled at the destination IP address.

Dynamic routing: even if one part of the network is knocked out (or congested), packets can be rerouted around the problem (see next slide).

High-speed backbones are fiber-optic trunk lines that criss-cross the globe.

Dynamic Routing

Dynamic routing is not “fixed”. A router can evaluate and determine the best path to take. For example, if a link is congested, dynamic routing can suggest another route.

High-Speed Backbones

http://www.youtube.com/watch?v=dOyKdJWPlZY

Virtual Private Networks (VPNs)

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.

What are the benefits of each type?

Virtual Private Networks use a combination of the two approaches. They are defined as a private network that uses a public network (most commonly the Internet), to establish a remote connection.

VPNs employ encryption and other security measures to make the connection secure.

Three Variations

1. Site-to-Site: A company uses a VPN to establish a secure connection between its distant branch offices (see next slide).

2. Computer-to-Site: While at home, an employee uses a company’s VPN to get secure remote access to company resources—e.g., files, applications, printers, etc.

3. Personal-use: I use a personal VPN provider like Tunnel Bear. They encrypt all communications I transmit wirelessly and over the Internet.

A Site-to-Site Virtual Private Network

RouterIntranetServer

Host System

IntranetServer

TheInternet

Fire wall

Fire wall

RouterExtranet

Benefits of VPNs Lower cost (Site-to-Site): lower cost / less

maintenance to build out a network of broad reach. Convenience (Computer-to-Site): savings in time

for employees if they don’t have to come into the office to work.

Browse privately and securely (personal use): snoopers (e.g., ISPs, marketers) cannot read your emails and communications; public Wi-Fi connections are more secure.

Restores your freedom (personal use): allows you to circumvent regional restrictions (i.e., geoblocking)