Data Communications-Midterm
Business Data Communications - ANS-The movement of information from one computer
application to an application on another computer by means of electrical or optical transmission
systems
Features of Computer Networks--Many of the basic principles have not changed for over 4
decades! - ANS-Common set of technologies support all networked computer applications
Therefore, any device attached to the network can perform these functions
Computer Networks--Applications: - ANS-email, IM , browser, client-server
Mobile Network Forecast-Data - ANS-Overall Mobile Data Traffic is Expected to Grow to 6.3
Exabytes / Month by 2015
Mobile Network Forecast-Video - ANS-Mobile Video Will Generate 66% of Mobile Data Traffic
by 2015
Computer Networks in Business - ANS-Chevron (CIO magazine, 2002)
Electronic level monitors in tanks at filling stations and satellite communication links between
filling stations and the inventory management system ensures that stations never run out of gas
The system has all but eliminated "retains," the aborted delivery because the tank is too full
Network Systems and Data Communications Analysts' Salary and Job Growth -
ANS-Projections by the Bureau of Labor Statistics (2006 - 2016)
Network systems and data communications analysts
2006 employment: 262,000
2016 projected employment: 402,000
Growth (23rd among all occupations): 140,000
Growth rate: 53% (highest among ALL occupations)
Multiplexing - ANS-Combines multiple channels of information on a common transmission
medium
Switching - ANS-Eliminates the need for point-to-point direct connections between every node
in a network
Circuit Switching - ANS-connection (circuit) is established before any data is sent and circuit is
"owned" until end of transmission and parties disconnect.
,Packet Switching - ANS-Routing data using addressed packets so that a channel is occupied
only during the transmission of the packet
Network resources are allocated as needed
First packet transmission occurred on Oct 29, 1969, in California
Used extensively in computer networks
Technology Milestone-Telegraph - ANS-Information carried as electrical signals over wires
Patented in the United States in 1840 by Samuel F. B. Morse
Technology Milestone-Multiplexing - ANS-One wire carries multiple signals
In 1874, the quadruplex telegraph developed by Thomas Edison transmitted two messages in
each direction simultaneously, for a total of four messages transiting the same wire at the same
time
Technology Milestone-Circuit Switching - ANS-One wire connects to multiple destinations
March 10, 1891, Strowger switch patented
Technology Milestone-Packet Switching - ANS-Signals sent and switching performed only when
information ready to be transferred
Highly efficient compared to circuit switching
First ARPANET transmission on Oct. 29, 1969
Packetization Overview - ANS-Packetization is
breaking down a message into small pieces (called packets)
these packets then independently traverse the network to their destination where they are
delivered and reassembled
Each packet has two parts
Data to be delivered
Overhead required for successful delivery and integration with other packets
Factors Favoring Packet Switching over Ciorcuit Switching - ANS-Increase in interactive data
traffic increases "burstiness" of data
(i.e., high ratio of peak usage to mean usage)
Packet switching enables efficient utilization of communication links by averaging needs among
large numbers of users
Allows for multitasking (concurrent access to the communication network)
Up to 100 times more efficient than circuit switching
"Bursty Traffic" - ANS-Increasing interactive data traffic increases "burstiness" of data
Circuit Switching - ANS-A circuit is an electronic closed-loop path among two or more points
Circuit switched networks typically bill by the minute
Packet Switching - ANS-Packet switches are called routers
, Routers are devices used to interconnect two or more networks
Packet switched networks typically bill by the MB
Layering - ANS-The hierarchical arrangement of functionality such that lower layers provide
functions and services that support the functions and services of higher layers
Advantages of Layering - ANS-Specializes technology development
Separation of functionality
Simplification in upgrades
Change from IPv4 to IPv6 does not require change in email clients or browsers
Simplification in adding new technology
Adding wireless network capability does not require change in web site addresses (URLs)
Packetization Requires: - ANS-We now know that data is sent as packets
Packetization requires:
specifying user commands (e.g., http://...)
segmentation and reassembly of packets
Identifying and locating packet destination
error control and correction
signaling
Much of this information needs to be included with the data in what is called a frame.
TCP/IP Stack - ANS-Core Technologies:
TCP - Transmission Control Protocol
IP - Internet Protocol
Integrates two popular sets of technologies:
TCP/IP
Ethernet
Modern Computer Networks use 4-Layers
OSI Model: - ANS-OSI - Open Systems Interconnection Architecture
Early networks involved vendor defined networking technologies:
Business Data Communications - ANS-The movement of information from one computer
application to an application on another computer by means of electrical or optical transmission
systems
Features of Computer Networks--Many of the basic principles have not changed for over 4
decades! - ANS-Common set of technologies support all networked computer applications
Therefore, any device attached to the network can perform these functions
Computer Networks--Applications: - ANS-email, IM , browser, client-server
Mobile Network Forecast-Data - ANS-Overall Mobile Data Traffic is Expected to Grow to 6.3
Exabytes / Month by 2015
Mobile Network Forecast-Video - ANS-Mobile Video Will Generate 66% of Mobile Data Traffic
by 2015
Computer Networks in Business - ANS-Chevron (CIO magazine, 2002)
Electronic level monitors in tanks at filling stations and satellite communication links between
filling stations and the inventory management system ensures that stations never run out of gas
The system has all but eliminated "retains," the aborted delivery because the tank is too full
Network Systems and Data Communications Analysts' Salary and Job Growth -
ANS-Projections by the Bureau of Labor Statistics (2006 - 2016)
Network systems and data communications analysts
2006 employment: 262,000
2016 projected employment: 402,000
Growth (23rd among all occupations): 140,000
Growth rate: 53% (highest among ALL occupations)
Multiplexing - ANS-Combines multiple channels of information on a common transmission
medium
Switching - ANS-Eliminates the need for point-to-point direct connections between every node
in a network
Circuit Switching - ANS-connection (circuit) is established before any data is sent and circuit is
"owned" until end of transmission and parties disconnect.
,Packet Switching - ANS-Routing data using addressed packets so that a channel is occupied
only during the transmission of the packet
Network resources are allocated as needed
First packet transmission occurred on Oct 29, 1969, in California
Used extensively in computer networks
Technology Milestone-Telegraph - ANS-Information carried as electrical signals over wires
Patented in the United States in 1840 by Samuel F. B. Morse
Technology Milestone-Multiplexing - ANS-One wire carries multiple signals
In 1874, the quadruplex telegraph developed by Thomas Edison transmitted two messages in
each direction simultaneously, for a total of four messages transiting the same wire at the same
time
Technology Milestone-Circuit Switching - ANS-One wire connects to multiple destinations
March 10, 1891, Strowger switch patented
Technology Milestone-Packet Switching - ANS-Signals sent and switching performed only when
information ready to be transferred
Highly efficient compared to circuit switching
First ARPANET transmission on Oct. 29, 1969
Packetization Overview - ANS-Packetization is
breaking down a message into small pieces (called packets)
these packets then independently traverse the network to their destination where they are
delivered and reassembled
Each packet has two parts
Data to be delivered
Overhead required for successful delivery and integration with other packets
Factors Favoring Packet Switching over Ciorcuit Switching - ANS-Increase in interactive data
traffic increases "burstiness" of data
(i.e., high ratio of peak usage to mean usage)
Packet switching enables efficient utilization of communication links by averaging needs among
large numbers of users
Allows for multitasking (concurrent access to the communication network)
Up to 100 times more efficient than circuit switching
"Bursty Traffic" - ANS-Increasing interactive data traffic increases "burstiness" of data
Circuit Switching - ANS-A circuit is an electronic closed-loop path among two or more points
Circuit switched networks typically bill by the minute
Packet Switching - ANS-Packet switches are called routers
, Routers are devices used to interconnect two or more networks
Packet switched networks typically bill by the MB
Layering - ANS-The hierarchical arrangement of functionality such that lower layers provide
functions and services that support the functions and services of higher layers
Advantages of Layering - ANS-Specializes technology development
Separation of functionality
Simplification in upgrades
Change from IPv4 to IPv6 does not require change in email clients or browsers
Simplification in adding new technology
Adding wireless network capability does not require change in web site addresses (URLs)
Packetization Requires: - ANS-We now know that data is sent as packets
Packetization requires:
specifying user commands (e.g., http://...)
segmentation and reassembly of packets
Identifying and locating packet destination
error control and correction
signaling
Much of this information needs to be included with the data in what is called a frame.
TCP/IP Stack - ANS-Core Technologies:
TCP - Transmission Control Protocol
IP - Internet Protocol
Integrates two popular sets of technologies:
TCP/IP
Ethernet
Modern Computer Networks use 4-Layers
OSI Model: - ANS-OSI - Open Systems Interconnection Architecture
Early networks involved vendor defined networking technologies:
