chap01 by gegeshandong

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									Changes in Telecommunications



          Chapter 1



                                1-1
   Knowledge Checkpoints
 The nature of data communications
 The data communications industry
 Telecommunications infrastructure
 Standards organizations
 Defining business needs for technology
How Does Data Move?




                      1-3
          The History of Data Movement

 5,000   years ago




                            • Conversation
                            • Chiseled stone/tablets
                            • Papyrus scrolls

What problems did these methods have?
    The History of Data Movement

 1,000   years ago




                                • Conversation
                                • Books
                                • Paper/hide scrolls
What problems did these methods have?
    The History of Data Movement

 500   years ago




                            • Courier
                            • Books
                            • Letters

What problems did these methods have?
    The History of Data Movement

 100   years ago




                            • Courier/Mail
                            • Telegraph
                            • Phone

What problems did these methods have?
    The History of Data Movement

 15   years ago




                                   • Mainframes
                                   • Modems
                                   • Fax machine
                                   • Diskettes
What problems did these methods have?
What Drives Data Movement?




                             1-9
    Why Study Data Communications?


  The key technology of the information age
  is communications networks.
 Technology enables global communication
  through the transmission of data.
        A Brief History of
     Communications in the U.S.

 1837    - Samuel Morse exhibited a working
  telegraph system.
 1876 - Alexander Graham Bell, invented the
  first telephone capable of practical use.
 1915 - first transcontinental telephone and
  first transatlantic voice connections
          A Brief History of
       Communications in the U.S.

 1947 - transistor invented in Bell Labs
 1951 - first direct long distance dialing
 1962 - first international satellite telephone call
 1968 - Carterfone court decision allowed non-Bell
  equipment to connect to Bell System Network
 1969 - Picturefone service began
 1984 - deregulation of AT&T
 1990s - cellular telephones commonplace
DATA COMMUNICATIONS
      NETWORKS




                      1-13
             Data Communications
Data Communications
  • The movement of computer information from one point
    to another by means of electrical or optical transmission
    systems.
  • Systems are called data communications networks.


Telecommunications
  • Includes the transmission of voice, video, and data
          Audience Question


What  are the business uses of the
 following types of transmissions?
 • Data, voice, and video
    The Major Players in the Data
      Communications Industry

 Judicial/political/legislative
 ISPs
 Vendors
 Carriers
 Manufacturers
 Customers (Residential & Business)
 Regulatory agencies
 Technology & research
 Standards organizations
     Lightening Round 1


   Give an example of each
 influencing entity in the data
communications industry and
describe their “interest” in the
           outcome

                                   1-17
The Telecommunications Jungle

                      Judicial            Internet Service
               Political / Legis lative      Providers


Standards m aking                                             Vendors /
  organizations                                              Cons ultants


  Technology /                    Data                        Carriers
   Res earch                  com m unications


  Regulatory                                               Manufacturers
  Agencies


                    Bus ines s              Res idential
                    cus tom ers             cus tom ers
NETWORK MODEL




                1-19
               Network Model

 A method of describing and analyzing data
  communications networks, by breaking the entire
  set of communications functions into a series of
  layers, each of which can be defined separately.
 This allows vendors to develop software and
  hardware to provide the functions separately.
Standards Organizations and Architectures


   OSI Standards
    • Reference Model of Open Systems
      Interconnection
    • Created by the International Telecommunications
      Union-Telecommunications Standards Sector
      (ITU-T)
    • And the International Organization for
      Standardization (ISO)
    • OSI standards dominate the data link and physical
      layers
          Other architectures specify the use of OSI standards at
           these layers
NETWORK STANDARDS




                    1-22
    The Importance of Standards

 The primary reason for standards is to ensure that
  hardware and software produced by different
  vendors can work together.
 The use of standards makes it much easier to
  develop software and hardware that link different
  networks because software and hardware can be
  developed one layer at a time.
   The Standards Making Process
Two types of standards:

Formal standards are developed by an
 official industry or government body.
Defacto standards emerge in the
 marketplace and are supported by several
 vendors, but have no official standing.
Standards Organizations and Architectures


   Architecture is a Design for Standards
    Creation
    • Specifies what types of standards are needed
      (application, transport, etc.)
    • After architecture is designed, individual standards
      of each type are created
          Analogy: architecture of house specifies what rooms will
           be needed and their relationships.
          After architecture is settled, individual rooms are
           designed
Standards Organizations and Architectures

   TCP/IP Standards
    • Created by the Internet Engineering Task Force
      (IETF)
    • Named after its two most widely known standards,
      TCP and IP
        TCP/IP is the architecture, while TCP and IP are
         individual standards
        However, these are not its only standards, even at the
         transport and internet layers
    • IETF standards dominate in corporations at the
      application, transport, and internet layers
          However, application, transport, and internet standards
           from other architectures are still used
  The Standards Making Process

The formal standardization process has 3 stages
1.Specification stage: developing a nomenclature and
  identifying the problems to be addressed
2. Identification of choices stage: those working on the
  standard identify the various solutions and choose the
  optimum solution from among the alternatives
3.Acceptance, the most difficult stage: defining the
  solution and getting recognized industry leaders to
  agree on a single, uniform solution
   Telecommunications Standards
          Organizations

International Organization for Standards
 (ISO)
  Member of the ITU, makes technical
   recommendations about data communications
   interfaces.
     TC Standards Organizations
• American National Standards Institute (ANSI)
• Institute of Electrical and Electronics Engineers
  (IEEE)
• Electronic Industries Association (EIA)
• National Institute of Standards and Technology
  (NIST)
• National Exchange Carriers Association (NECA)
• Corporation for Open Systems (COS)
• Electronic Data Interchange -(EDI) of Electronic
  Data Interchange for Administration Commerce
  and Transport (EDIFACT).
Telecommunications Infrastructure
     Voice and Video Networks

Telephone Network--PSTN
  Customer premises (home or office)
  Local loop (access line) connects customer
   premises to first switching office
                                     Switching (Central)
             Local Loop              Office
            (Access Line)

                            Connection

              Customer                     Customer
              Premises                     Premises
     Voice and Video Networks
 Hierarchy    of switches (LATAs)
                                     POP
 Trunk   lines connect switches
                                              Switch
                         POP
                               IEC
            Trunk Line
                                                LATA 1

      Switch                         LATA 2
The Relationship Between LATAs
                                     Belongs to LEC
                                 (Local-Exchange Carrier)
                          C.O.
Phone                                                       Phone
           Local loop


                                                    Local loop

                        Inter-exchange
                                         LATA - B
LATA - A                    circuit


             P.O.P.                                         C.O.
                                         P.O.P.
                        Belongs to IXC
                   (Inter-eXchange Carrier)
        Voice and Video Networks

Circuit
  End-to-End Connection between
   phones
  Pass through multiple switches &
   trunk lines




                                  Circuit
                Circuit
        Voice and Video Networks

Reserved Capacity
 Circuit capacity is reserved during
  duration of each call
 At each switch              Reserved
                              Capacity
 On each trunk line
                     Reserved
                     Capacity

                                Circuit
         Voice and Video Networks

   Reserved Circuit Capacity Guarantees Throughput
    • Never get less than reserved capacity
    • No congestion
   Reserved Circuit Capacity is Expensive
    • Pay for it whether you use it or not
    • Good for voice, because conversations are fairly constant
    • Bad for data, because most data transmission is bursty;
      e.g., on the Internet, download, then stare at screen for a
      long time until next download
                Bandwidth
 The capacity of media to carry data
 Large capacity enables video
 Small capacity limits type of data (analog
  phone lines)
 Bandwidth is measured in bits per second
  (speed of travel down the “pipe”
         Audience Question

 What   is happening to LECs?
 Is their business profitable?
 What is the direction of
  technology with respect to voice
  transmission?
          The Top-Down Approach

                     Business



                    Application

Requirements                        Solutions
                       Data


                     Network



                    Technology

 Which is reviewed first: requirements or solutions?
        Knowledge Checkpoints

 How are data and transmission different?
 Name the major trends in telecomm industry
 Describe how a phone call works
 Name 2 major standards organizations
 How do you define the business needs for
  technology?
 How does data relate to bandwidth?
         Lightening Round II
What do the acronyms stand for?

 CO
 IXC
 LATA
 LEC
 PSTN
 ISO
 IETF
 BPS

								
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