1-1 Chapter 1 Changes in Telecommunications
Dec 19, 2015
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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
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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?
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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.
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
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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
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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
Judicial Political / Legislative
Standards making organizations
Vendors / Consultants
Technology / Research
Carriers
Regulatory Agencies
Manufacturers
Data communications
Residential customers
Business customers
GOLDMAN & RAWLES: ADC3e FIG. 01-01
Internet Service Providers
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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
Other architectures specify the use of OSI standards at these layers
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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
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--PSTNCustomer premises (home or office)Local loop (access line) connects
customer premises to first switching office
Connection
Switching (Central)OfficeLocal Loop
(Access Line)
CustomerPremises
CustomerPremises
Voice and Video Networks
Hierarchy of switches (LATAs)
Trunk lines connect switches
Switch
Trunk Line
POP
POP
LATA 1
LATA 2
IEC
Switch
The Relationship Between LATAs
Phone Local loopC.O.
P.O.P.
Phone
C.O.P.O.P.
Local loop
Inter-exchange circuit
Belongs to IXC (Inter-eXchange Carrier)
Belongs to LEC (Local-Exchange Carrier)
LATA - A
LATA - B
GOLDMAN & RAWLES: ADC3e FIG. 01-03
Voice and Video Networks
CircuitEnd-to-End Connection between
phonesPass through multiple switches &
trunk lines
CircuitCircuit
Voice and Video Networks
Reserved CapacityCircuit capacity is reserved during
duration of each callAt each switchOn each trunk line
Circuit
ReservedCapacity
ReservedCapacity
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?