MD 240 Telecommunications and the Internet

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MD 240Telecommunicationsand the Internet
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Overview

• Background
• Telecommunications Concepts
• Network Technology
• Networked Computing Architectures
• Managing Networks

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Background
4
Background

• Early Network Technologies
• 1791 French develop Optical Telegraph Network
  uses cross-arms and pulleys for signals
• 1837 Samuel Morse demonstrates the electric
  telegraph
• 1845 Morse Magnetic Telegraph Company founded,
  makes revenue of 413 in October
• U.S. Postmaster General declares that telegraph
  network will never be profitable
• 1873 Western Union holds assets of 40 Million
• 1886 First telemarketing Richard Sears sells
  watches via telegraph

(Source www.silkroad.com/net-history.html)
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BackgroundHistory

• Early Network Technologies
• 1876 Alexander Graham Bell invents phone
• 1879 Phone service costs businesses 40/month
• 1902 Marconi sends wireless signal across
  Atlantic
• 1930 Telephone network outgrows telegraph
  network
• 1960s Packet switching invented proposed as
  basis for ARPANET
• 1969 First computer handshake takes place
• 1970 4 node ARPANET is born
• 1972 First electronic mail message

(Source www.silkroad.com/net-history.html)
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BackgroundHistory

• Early Network Technologies
• 1984 NSF builds 6 node NSFNET running at 56
  kbps
• 1988 U.S. Government mandates the OSI Protocol
• 1990 ARPANET shuts down, having been superceded
  by NSFNET (300,000 nodes and growing). NSFNET
  backbone upgraded to 1.5 Mbps
• 1990 Internet services ARCHIE, GOPHER, and WAIS
  appear
• 1992 Mosaic browser written, leading to
  development of Netscape Navigator WWW is born
• 2003 Affordable 802.11g Wi-Fi network devices
  communicate at 54Mbps

(Source www.silkroad.com/net-history.html,
http//www.computerhistory.org/exhibits/internet_h
istory/index.page)
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BackgroundHistory

• 1990
• Local Area Networks (LAN) come onto the scene
• business case for LANs not obvious, most managers
  asking What is a network?
• Wide Area Networks (WAN) a strategic technology
  but only affordable for the largest
  corporations
• Ex DDB Needham built a new corporate
  headquarters in Chicago just so that they could
  have it fully wired and integrated into a new WAN

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Background

• Today
• LAN -
• Affordable network hardware (50-200/device)
• Cable Modem can affordably connect home/office
  network to Internet and WWW (lt100/month)
• WAN -
• most corporations, big and small, have access to
  the Internet
• T1 access lt 1000/month, Digital Subscriber Line
  (DSL) even less

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Background Small Office LAN
To ISP and WWW
16-port Eth. Switch
4-port F.Eth. Hub
DSL Modem
TCP/IP Fast Ethernet Router
USB Device
Linux File Server for Windows Network (Samba
program)
Windows NT Client
8-Port Fast Ethernet Switch
Windows 2000 Application Server
Windows 95 Client
BW Laser Printer
Color Laser Printer
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BackgroundCorporate WAN
PBX
Modem pool
Boston
router
host computer
San Francisco
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BackgroundFuture Networking

• Internet 2 (www.internet2.org)
• Cooperative effort (in USA only) to develop next
  generation of the Internet (NGI)
• Government
• Research Universities
• Industry
• Internet 2 website reports on emerging network
  technologies and networked applications
• BC is now an Internet 2 member org. (as of Dec.
  2001)
• Efforts now being made to build a world-wide
  Internet2 network to allow academics to
  collaborate
• ABILENE 10 Gbps network

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Telecommunications Concepts
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Telecommunication ConceptsDefinitions

• Telecommunication
• long-distance communication through the use of
  common carriers, including telephone, television,
  and radio.
• Data Communications
• Electronic collection, exchange, and processing
  of data or information, including text, pictures,
  voice, and other information that is digitally
  coded and intelligible to a variety of electronic
  machines

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Telecommunication Concepts Electronic Signals

• Analog Signals
• continuous waves that carry information by
  altering the characteristics of the waves
• amplitude and frequency
• Digital Signals
• discrete on-off pulses that convey information in
  terms of 1s and 0s, just like the central
  processing unit in computers

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Telecommunication ConceptsMajor Task
Examples Modem copper phone line (analog) into
(digital) bits for fiber optic transmission Video/
TV VHS tape (analog) into (digital) MPEG for
internet/satellite transmission
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Network Technology
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Networking Protocols

• Protocol
• A set of rules and procedures governing
  transmission across a network
• Some protocols
• TCP/IP
• FTP
• SMTP
• http//
• gopher//

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Networking Software ProtocolsOpen Systems
Interface (OSI) Reference Model
7 6 5 4 3 2 1
User interface, file transfer, electronic mail
programs
Application Layer
FTP SMTP Telnet
Data formatting and character code conversion
Presentation Layer
Negotiation and establishment of a connection
between two computers (nodes)
Session Layer
TCP UDP
Provision for end-to-end data delivery
Transport Layer
User interface, routing of information packets
across multiple networks
Network Layer
IP
Transfer of units of information, error checking
Link Layer
IEEE 802 X.25
Transmission of raw data over a communications
channel
Physical Layer
Each layer depends on the layer below it.
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Networking Software ProtocolsExample Modem
OSI Layer 7
Hardware
Telecommunication media (channels)
OSI Layer 6
Front end processor
OSI Layer 3
OSI Layer 2
Receiver
OSI Layer 5
OSI Layer 4
OSI Layer 1
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Networking Transmission ProtocolsBased Upon the
OSI Reference Model

• NetBEUI
• Microsoft-only networks
• IPX/SPX
• Novell Network, limited support, dying a slow
  death
• AppleTalk
• Apple-only networks
• TCP/IP
• Microsoft networking, Apple networking,
  UNIX/Linux networking ... all support it
• PPTP (Point-to-Point Tunneling Protocol)
• used for Virtual Private Networks wraps around
  NetBEUI
• DHCP (Dynamic Host Configuration Protocol)
• dynamically assigns IP addresses to computers on
  a TCP/IP LAN

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Networking Hardware

• Workstation computers
• Server computers/Mainframe computers
• Network interface cards (NICs)
• Inter-connection hardware
• Cabling
• Unshielded twisted pair (UTP) cable
• Shielded twisted pair (STP) cable
• Coaxial cable
• Fiber-optic cable

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Networking Hardware

• Wide Area Network (WAN)
• A network that spans hundreds of feet to
  thousands of miles
• Purpose is linking together other networks
• A network of networks
• Local Area Network (LAN)
• A network in which the devices are all fairly
  close to one another
• The goal is to connect all of the devices
• A network of devices

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Networking Hardware

• Wide Area Network (WAN) Inter-Connection Hardware
• Repeater
• a reamplification device, receives a message and
  passes it along
• Bridge
• connects two networks together at OSI network
  layer 2
• dumb cannot translate messages from one
  protocol into another
• Router
• an intelligent bridge, works at OSI network
  layer 3
• understands network addresses where messages are
  going, and can route them to the computer
• Gateway
• an intelligent router, works at OSI network
  layers 4-7
• connects two different types of networks (e.g.,
  AppleTalk and TCP/IP)
• translates data from one protocol into another
  (e.g., TCP/IP into AppleTalk)
• also provide bridging and network layer
  routing services

Dumb
Intelligent
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Networking Hardware

• Local Area Network (LAN) Inter-Connection
  Hardware
• Hub
• passes messages between two computers by
  broadcasting packets to every computer on network
• only one computer can talk at a time
  potentially wastes network bandwidth
• Switch
• an intelligent hub
• passes messages between two computers by creating
  a direct connection between the two computers
• multiple computers can talk directly to each
  other at the same time makes better use of
  network bandwidth

Dumb
Intelligent
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Network Topology

• Topology
• The shape of a network the networks layout
• Most Common Network Topologies
• Star Topology
• Ring Topology
• Bus Topology
• Mesh Topology
• Tree (Hybrid) Topology

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Network TopologiesStar
USER
USER
USER
HOST
USER
Stations linked to a central node, but each
transmission is heard by all users (if host
device is a hub)
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Network TopologiesRing
USER
USER
USER
HOST
One way transmission, listen and re-transmit,
common example is IBMs Token Ring network
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Network TopologiesBus
USER
USER
USER
terminator
terminator
USER
USER
USER
Stations linked to a central cable, easy to add
new users
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Network TopologiesMesh
USER
USER
USER
USER
USER
USER
Devices are connected with many redundant
interconnections
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Network Topology

• Which to Choose?
• Depends
• Cost
• Reliability/failsafe requirements
• Organizations mix and match, depending on the
  type of use
• Ring connects routers on a network
• Star connects end users in a local workgroup

Hybrid Topology
Tree Topology
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Network TechnologyLayout and Implementation
Issues

• Distance (some media are limited)
• Range of services (data, voice, video)
• Security (encryption)
• Multiple access (capacity issues)
• Utilization (light vs. heavy use)
• Cost justifiable (per user)
• Installation (centralized)
• Allow for growth and expansion (people /
  equipment)
• Facilitate service and maintenance (upgrades)

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Networks Make Possible ...Many Architectures
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Client/Server ArchitecturesSeparating
Presentation, Application Logic, and Database
Computer 1
Computer 2
Computer 3
revenue get_data() profit revenue - cost
income.report( profit, revenue)
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Client/Server ArchitecturesDistributing
Presentation Logic, Application Logic, and
Database Mgmt

• Distributed Presentation
• Client manages only a portion of presentation
  processing tasks
• Server manages presentation, application,
  database
• Remote Presentation
• Client presentation logic
• Server application logic and database management
• Distributed Function
• Client presentation logic and part of
  application
• Server part of application and database
  management
• Remote Data Management
• Client presentation logic and application logic
• Server database management
• Distributed Data Management
• Client manages presentation, application logic,
  and portion of database
• Server manages part of database

More and more of presentation, application, and
database logic become positioned on client
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Internet Technology HTML File-Based Website
Source Philip and Alexs Guide to Web
Publishing, http//www.arsdigita.com/books/panda/
36
Internet Technology Website Built from Common
Gateway Interface (CGI) Program (2-Tier)
Tier 1
Tier 2
Source Philip and Alexs Guide to Web
Publishing, http//www.arsdigita.com/books/panda/
37
Tier 1
Internet Technology CGI Program Requests Data
from Database (3-Tier)
Tier 2
Source Philip and Alexs Guide to Web
Publishing, http//www.arsdigita.com/books/panda/
Tier 3
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Scripting Languages ASP JSP CFM
Internet Technology 3-Tier Database-Backed Websit
e
index.asp
Source Philip and Alexs Guide to Web
Publishing, http//www.arsdigita.com/books/panda/
39
Internet Technology SecureN-Tier Website
Architecture
Source Philip and Alexs Guide to Web
Publishing, http//www.arsdigita.com/books/panda/
40
N-Tier ArchitectureMSNBC.com
Web Servers
Database Servers
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Internet TechnologyAn Enterprise-Wide Network
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Managing Enterprise Networks
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Management ObjectivesOpen Systems and Enterprise
Networking

• Connectivity
• the ability of the various computer resources to
  communicate with each other through network
  devices without human intervention
• Portability
• the ability to move applications, data, and even
  people form one system to another with minimal
  adjustments
• Interoperability
• the ability of systems to work together by
  sharing applications, data, and computer
  resources.
• Scalability
• the ability to run applications unchanged on any
  open system where the hardware can range form a
  laptop PC to a super computer

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Managing Enterprise NetworksPresent Trends

• Enterprise Application Integration (EAI)
• Organizations have legacy mainframe
  applications
• old systems and applications originating waaay
  back in time
• organizations have added ERP, CRM, etc., to these
• Organizations already have built enterprise
  network to try to link desktops together
• make the office workers desktop resources
  flexible
• Many other digital devices now used by enterprise
• PDAs, Cash Registers, Laptops, Machines
• Now, integrating them through software that
• wraps around a device and serves as an
  interface between that device and other objects
  in the enterprise that are allowed to communicate
  with it

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Managing Enterprise NetworksIssues of Concern

• Choose network design satisfactory for user needs
• Procure network components
• Tracking inventory of network hardware
• Network maintenance
• Network failure detection
• Billing customers (internal external) who use
  the network resources

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Managing Enterprise NetworksTools for Managing
Networks

• Operations Support Systems (OSS)
• Network Planning
• Network Design
• Pre-Implementation Network Analysis
• Visual Layout Tools
• Simulation of System Design
• Network Management
• Inventory of computers, routers, hubs, etc.,
  etc.,
• Failure analysis
• OSS Customer Relationship Management

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Managing Enterprise Networks Operations Support
Systems
OSS Pictures
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Networking Jobs

• Network Engineer
• Average starting salary 62,250-87,000
• Skill requirements
• Microsoft Certified Systems Engineer (MCSE)
• Cisco Certified Internet Expert (CCIE)
• Security related hardware and software experience
• LAN/WAN management and systems administration
• Background in Virtual Private Networks (VPNs),
  TCP/IP, intrusion detection, firewall
  implementation
• Whos hiring
• Financial services, government
• (Vaas, L., Networking Skills Still Crucial,
  eWeek, Dec. 31, 2001, p. 33)