1-1 Chapter 1 Changes in Telecommunications

Knowledge Checkpoints  The nature of data communications  The data communications industry  Telecommunications infrastructure  Standards organizations  Defining business needs for technology

1-3 How Does Data Move?

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 Conversation Books Paper/hide scrolls  1,000 years ago What problems did these methods have?

The History of Data Movement Courier Books Letters  500 years ago What problems did these methods have?

The History of Data Movement Courier/Mail Telegraph Phone  100 years ago What problems did these methods have?

The History of Data Movement Mainframes Modems Fax machine Diskettes  15 years ago What problems did these methods have?

1-9 What Drives Data Movement?

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.  Samuel Morse exhibited a working telegraph system.  Alexander Graham Bell, invented the first telephone capable of practical use.  first transcontinental telephone and first transatlantic voice connections

A Brief History of Communications in the U.S.  transistor invented in Bell Labs  first direct long distance dialing  first international satellite telephone call  Carterfone court decision allowed non-Bell equipment to connect to Bell System Network  Picturefone service began  deregulation of AT&T  1990s - cellular telephones commonplace

1-13 DATA COMMUNICATIONS NETWORKS

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

1-17 Lightening Round 1 Give an example of each influencing entity in the data communications industry and describe their “interest” in the outcome

The Telecommunications Jungle

1-19 NETWORK MODEL

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 v Other architectures specify the use of OSI standards at these layers

1-22 NETWORK STANDARDS

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 v Analogy: architecture of house specifies what rooms will be needed and their relationships. v 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 v TCP/IP is the architecture, while TCP and IP are individual standards v 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 v 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 Connection Switching (Central) Office Local Loop (Access Line) Customer Premises Customer Premises

Voice and Video Networks  Hierarchy of switches (LATAs)  Trunk lines connect switches Switch Trunk Line POP LATA 1 LATA 2 IEC Switch

The Relationship Between LATAs

Voice and Video Networks  Circuit  End-to-End Connection between phones  Pass through multiple switches & trunk lines Circuit

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

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 Data Network Technology Application Requirements Solutions 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  CO  IXC  LATA  LEC  PSTN  ISO  IETF  BPS What do the acronyms stand for?