Transcript Telecommunications and Networking

Telecommunications
and Networking
Network Concepts
• Network
– An interconnected chain, group or system
• Number of possible connections on a
network is N * (N-1)/2
– Where N = number of nodes (points of
connections on the network)
– Example, if there are 10 computers on a
network, there are 10 * 9 = 90 possible
connections
Metcalfe’s Law
• The usefulness of a network equals the
square of the number of users
• On a small network, a change in technology
affects technology only
• On a large network like the Internet, a
change in technology affects social, political
and economic systems
Telecommunications
• Telecommunications
– Exchange of information in any form (voice,
data, text, images, audio, video) over networks
Basic concepts
• Communication protocols (TCP/IP)
• Data transmission methods
– Asynchronous
– Synchronous
• Connecting
– Modem and TCU
– Hardwired and remote
• Data transmission channels (bps)
– narrow bands: 5-30
– voice bands: 1,000-9,600
– broad bands: 100,000
• Types of communication lines
– simplex
– half-duplex
– duplex
Networks
• Concept
– "a group of interconnected computers, workstations, or computer devices
(such as printers and data storage systems).”
• Network topology
– bus
– star
–
ring
• Local-area networks
– bus: Ethernet, carrier sense multiple access (CSMA)
– ring: token passing method
• Distributed data processing
– "interconnects sites of one organization not only for communication of data
and messages but also for
the sharing of resources."
Open Systems
• Information systems that use common standards for hardware,
software, applications and networks
• Internet networking technologies are a common standard for open
systems
• Connectivity:
– Ability of networked computers to easily access and communicate
with each other and share information
• Interoperability:
– The ability of an open system to enable end user applications to be
accomplished using different varieties of computer systems,
software packages, and databases provided by a variety of
interconnected networks
Middleware
• Any programming that serves to “glue
together” two separate programs
Internet2
• Next generation of the Internet
• High-performance network
• In use at 200 universities, scientific
institutions, communications corporations
The Internet
• No central computer system
• No governing body
• No one owns it
Internet Service Provider
• ISP
– A company that specializes in providing easy
access to the Internet
– For a monthly fee, you get software, user name,
password and access
• ISPs are connect to one another through
network access points
An Intranet
• A network inside an organization
– That uses Internet technologies (such as Web browsers
and servers, TCP/IP protocols, HTML, etc.)
– To provide an Internet-like environment within the
organization
– For information sharing, communications, collaboration
and support of business processes
– Protected by security measures
– Can be accessed by authorized users through the
Internet
Extranet
• Network links that use Internet technologies
– To connect the Intranet of a business
– With the Intranets of its customers, suppliers or
other business partners
GPS
1. The global positioning system (GPS) is a major
technological achievement that has broad-reaching
implications for business. Using the Internet,
– Can find other innovative uses for GPS.
– Good places to start familiarizing yourself with
current accomplishments are
The GPS Overview at
http://www.colorado.edu/geography/gcraft/notes/gps/
gps_f.html
Telecommunications network
• Any arrangement where a sender transmits
a message to a receiver over a channel
consisting of some type of medium
Types of Networks
•
•
•
•
WAN
LAN
VPN
C/S
VPN
VPN
• Basically, a VPN is a private network that uses a
public network (usually the Internet) to connect
remote sites or users together. Instead of using a
dedicated, real-world connection such as leased
line, a VPN uses "virtual" connections routed
through the Internet from the company's private
network to the remote site or employee.
Source: computer.Howstuffworks.com
Internetwork Processors
• Switch – makes connections between
telecommunications circuits in a network
• Router – intelligent communications
processor that interconnects networks based
on different protocols
• Hub – a port switching communications
processor
• Gateway – connects networks using
different communications architectures
ROUTERS
Routers are specialized computers that send
your messages and those of every other
Internet user speeding to their destinations
along thousands of pathways.
•
Fujitsu GeoStream R980 industrial strength router
ROUTERS
configuration table. A configuration table is a collection of
information, including:
• Information on which connections lead to particular groups
of addresses
• Priorities for connections to be used
• Rules for handling both routine and special cases of traffic
A router, then, has two separate but related jobs:
• The router ensures that information doesn't go where it's
not needed. This is crucial for keeping large volumes of
data from clogging the connections of "innocent
bystanders."
• The router makes sure that information does make it to the
intended destination.
Distributed data processing
TSS - Time Sharing Systems
PC
PC
PC
MAINFRAME
CSS - Client Server Systems
PC
Client/Server networks
• Clients: End user personal computers
or networked computers
• Interconnected by LANs
• Servers: manage networks
• Processing shared between clients and
servers
CSS architecture
Remote
Server
File
Server
Communications Server
Print
Server
LA N
PC
PC
PC
PC
Peer-to-peer networks
• Networks that connect from one PC to another PC
Peer-to-peer networking enables or enhances the
following scenarios:
• Real-time communications (RTC)
• Collaboration
• Content distribution
• Distributed processing
• Improved Internet technologies
Source: www.microsoft.com
Wireless Technologies
• Terrestrial microwave
– Earthbound microwave systems that transmit
high-speed radio signals in a line-of-sight path
– Between relay systems spaced approximately
30-miles apart
• Communications satellites
– Satellite serves as relay stations for
communications signals
– Uses microwave radio signals
Wireless Technologies
• Cellular and PCS telephone and pager systems
– Divide the geographic area into small areas or cells
– Each cell has transmitter or radio relay antenna to send
message from one cell to another
• Wireless LANs
– Radio signals within an office or building
– Connect PCs to networks
• Bluetooth
– Short-range wireless technology
– To connect PC to peripherals such as printer
Bluetooth
• Bluetooth is a standard developed by a group of
electronics manufacturers that allows any sort of
electronic equipment -- from computers and cell
phones to keyboards and headphones -- to make
its own connections, without wires, cables or any
direct action from a user.
• Bluetooth can connect up to eight devices
simultaneously. With all of those devices
in the same 10-meter (32-foot) radius
Wireless Networks
• http://www1.us.dell.com/content/topics/glo
bal.aspx/solutions/en/truemobile?c=us&cs=
04&l=en&s=bsd
• (see the LIVE demo on the site)
Steps in wireless network
source: www.dell.com
EDI Concepts
• EDI is a mechanism for electronic trading
• EDI replaces paper flow with online transactions
• EDI architecture
• EDI is for trading partners
• Implementation plan is a key factor
• Obstacles:
•
– lack of transaction standardization
– high start-up costs
EDI third-party suppliers
– AT&T, Control Data, EDS, GE, Western Union, IBM, Martin Marietta
Data Systems, etc.
EDI architecture
Trading Partner 1
Trading Partner 2
CONFIRMATION
standard
transactions
Transaction
Converter
Transaction
Converter
Acquisition System
system
transactions
system
transactions
CONFIRMATION
Order Entry System
ORDER
ORDER
Network Topologies
• Topology: structure of a network
• Star: ties end user computers to a central
computer
• Ring: ties local computer processors together in
a ring on a relatively equal basis
• Bus: local processors share the same
communications channel
Network Architectures &
Protocols
• Protocol: standard set of rules and
procedures for the control of
communications in a network
• Network Architecture:
– Master plan of standard protocols, hardware,
software and interfaces between end users and
computer systems
– Goal of promoting an open, simple, flexible,
and efficient telecommunications environment
OSI & TCP/IP Models
• Open Systems Interconnection (OSI) Model
– A seven-layer model that serves as a standard
model for network architectures
– Model for how messages should be transmitted
between two points in a network
– Each layer adds functions
• Transmission Control Protocol / Internet
Protocol (TCP/IP)
– A five layer telecommunications protocol used
by the Internet
Basic Communications Model
Standards are needed at all Layers
User Layer
Application Layer
Computer (Transport) Layer
Transmission Layer
Internet Telephony
• Using an Internet connection to pass voice
data using IP
• Voice over IP (VoIP)
• Skips standard long-distance phone charges
VOIP (source www.fcc.gov)
Bandwidth
• Bandwidth
– Frequency range of a telecommunications
channel
– Determines transmission rate
– Classified in bits per second (bps)
• Transmission Rates:
– Narrow-band – low-speed
– Broadband – high-speed
Transmission Speeds
Wi -Fi
• Wi_fi
• Wi_Max
RFID
• RFID & Controversy