Chapter 1 TextBook Flashcards
What are the three forces driving the evolution of data communications and networking facilities?
Traffic growth, development of new services, advances in technology
How has communication traffic changed over the decades?
It has grown at a high and steady rate, now including voice, data, image, and video
What is the impact of the increasing demand for web services and mobile access on businesses?
Businesses are pressured to increase communication capacity in cost-effective ways
What has caused the explosion of mobile broadband traffic?
Increased data demand from smartphones and tablets, along with high-quality service expectations
What are the four notable technology trends in data communications?
- Faster and cheaper computing and communications
- More intelligent networks
- Dominance of the Internet and Web applications
- Mobility as a new frontier for ICT
What does QoS stand for in networking?
Quality of Service
What is the significance of dense wavelength division multiplexing (DWDM)?
It enables communication traffic to be carried by fiber optic cables at rates of multiple terabits per second
How often does Internet backbone data rate demand typically double?
Approximately every 18 months
True or False: Today’s networks can provide customizable services in network management and security.
True
What characterizes the migration to ‘everything over IP’?
Opportunities and challenges for ICT managers in reaching customers, suppliers, and partners
Fill in the blank: The trend of _______ has liberated workers from the confines of the physical enterprise.
mobility
What percentage of traffic typically remains local in a business environment?
About 80%
What are two examples of consumer electronics driving increased traffic on networks?
- Digital versatile disks (DVDs)
- Digital still cameras
What is convergence in the context of telecommunications?
The merger of previously distinct telephony and information technologies and markets
What are the three layers of the convergence model?
- Applications
- Enterprise services
- Infrastructure
What key aspect of infrastructure convergence allows voice, image, and video to be carried over networks?
Packet-based transmission using the Internet Protocol (IP)
What has driven the emergence of high-speed LANs in business environments?
The widespread acceptance of personal computers and the need for high-speed data transfer
What are server farms used for in high-speed LANs?
To allow client systems to draw large amounts of data from centralized servers
What has changed in corporate wide area networking needs since the early 1990s?
A shift from centralized computing to more dispersed employee locations and telecommuting
What type of applications have increased reliance on personal computers and servers?
Client/server computing and intranet computing
What does convergence in telecommunications involve?
Moving voice into a data infrastructure and integrating all voice and data networks into a single data network infrastructure
This includes extending the network into wireless communication.
What is the fundamental purpose of a communications system?
The exchange of data between two parties.
What are the key elements of a communications model?
- Source
- Transmitter
- Transmission system
- Receiver
- Destination
What role does a transmitter play in a communications model?
Transforms and encodes the information to produce electromagnetic signals for transmission.
What is the function of a receiver in a communications model?
Accepts the signal from the transmission system and converts it into a form that can be handled by the destination device.
What is transmission system utilization?
Making efficient use of transmission facilities shared among multiple communicating devices.
What is multiplexing?
Techniques used to allocate the total capacity of a transmission medium among multiple users.
What is error detection and correction in data communications?
Processes required to identify and fix errors in transmitted signals.
What is flow control?
Ensures that the source does not overwhelm the destination by sending data too quickly.
What does addressing refer to in a communications system?
Indicating the identity of the intended destination for transmitted data.
What is routing in data communications?
Choosing a specific path through a network for data transmission.
What is the difference between error correction and recovery?
Error correction fixes errors in data, while recovery techniques resume interrupted information exchanges.
What is message formatting?
Agreement on the form of the data to be exchanged or transmitted.
What is the significance of network management in data communications?
Needed to configure, monitor, and manage the communication system effectively.
What are the major transmission media used in data communications?
- Twisted-pair lines
- Coaxial cable
- Optical fiber cable
- Terrestrial and satellite microwave
What is the impact of fiber optic communication on data transmission?
Offers high capacity and security, leading to its widespread adoption in long-distance and local communications.
What is the trend towards wireless transmission in communications?
Supports universal personal telecommunications and access to communications.
What are the two major approaches to increasing transmission efficiency?
- Multiplexing
- Compression
Fill in the blank: The basic building block of any enterprise network infrastructure is the _______.
[transmission line]
True or False: The properties of the signal must allow it to be propagated through the transmission system and be interpretable at the receiver.
True
What must be established for effective communication between the transmitter and receiver?
Synchronization between the two parties.
What is the role of a modem in data communications?
Converts digital signals from a computer into analog signals for transmission over telephone networks.
What is the purpose of encoding information into an electromagnetic signal?
To determine how information is transmitted, affecting performance and reliability.
What must be agreed upon between a device and the transmission medium?
The interface.
What functions are performed by a data link control protocol?
Controlling the flow of information and recovering from its loss or corruption.
What are the two main objectives to maximize transmission efficiency?
- Maximize information carried over a resource
- Minimize transmission capacity needed.
What are the three most common multiplexing techniques?
- Frequency division
- Synchronous time division
- Statistical time division.
What was the forecasted number of Internet users in 2016?
Approximately 3 billion users.
How many fixed and mobile networked devices were estimated in 2016?
Over 20 billion devices.
What was the forecast for total annual Internet traffic in 2016?
From 372 exabytes to 1.3 zettabytes.
What type of network is commonly found in medium- and large-size office buildings?
Local Area Network (LAN).
What has contributed to the proliferation of LANs in enterprises?
Development of internationally recognized standards.
What is the dominant LAN architecture?
Ethernet.
What is integration in the context of LANs?
Communication equipment and networks dealing simultaneously with voice, data, image, and video.
What are the two traditional technologies for WAN implementation?
- Circuit switching
- Packet switching.
What is a characteristic of circuit-switching networks?
A dedicated communications path is established between two stations.
In packet-switching networks, what are the small chunks of data called?
Packets.
What type of network was developed to take advantage of high data rates and low error rates?
Frame relay.
What is the primary difference between frame relay and ATM?
Frame relay uses variable-length packets, while ATM uses fixed-length packets.
What does ATM stand for?
Asynchronous Transfer Mode.
What is the typical geographic scope of a LAN?
A single building or a cluster of buildings.
What are the common configurations of LANs?
- Switched LANs
- Wireless LANs.
What is one of the advantages of wireless networks?
Mobility.
When was the ARPANET developed?
1969.
Who developed the protocols for internetworking that formed the basis for the Internet?
Vint Cerf and Bob Kahn.
What does IP stand for?
Internet Protocol.
What does a host refer to in the context of the Internet?
A computer connected to the Internet.
What is the role of a router in the Internet?
To connect different networks and make routing decisions.
What is Customer Premises Equipment (CPE)?
Telecommunications equipment located on the customer’s premises.
What does CPE stand for?
Customer Premises Equipment
Refers to telecommunications equipment located on the customer’s premises.
Give examples of Customer Premises Equipment (CPE).
- Telephone handsets
- Modems
- Cable TV set-top boxes
- Digital subscriber line routers
What is an Internet Service Provider (ISP)?
A company that provides access to the Internet
ISPs have the equipment and telecommunication line access required to have a POP.
What does NAP stand for?
Network Access Point
Major Internet interconnection points that tie ISPs together.
List the original four Network Access Points (NAPs) in the United States.
- New York
- Washington, D.C.
- Chicago
- San Francisco
What is the role of a Network Service Provider (NSP)?
Provides backbone services to an Internet Service Provider (ISP).
Define Point of Presence (POP).
A site with telecommunications equipment that allows users to connect to the ISP network.
What is the typical connection speed of a T-1 circuit?
1.544 Mbps
What is the typical connection speed of a T-3 circuit?
44.736 Mbps
What is the ‘local loop’ in telecommunications?
Infrastructure between a provider’s installation and the site where the host is located.
What type of cable is typically used in a residential DSL connection?
Copper telephone line
What type of cable is typically used in a residential cable modem connection?
Coaxial cable
What does the ISP provide to home users?
- Unique numeric IP address
- Name resolution
- Access to other ISP networks
True or False: A local loop provider is always the same as the ISP.
False
What is the primary service provided by a Network Access Point (NAP)?
Infrastructure to move data between connected networks.
What technology is commonly used in modern NAPs?
ATM and Gigabit Ethernet
What is the role of routers in an IP backbone network?
Provide connectivity to external networks and users.
What is wavelength division multiplexing (WDM)?
A technology that allows multiple logical channels on an optical link.
What are edge routers used for?
To connect external networks and users to the backbone.
What is the capacity requirement range for aggregation routers by 2020?
200 Gbps to 400 Gbps per optical link
What is the capacity requirement range for core routers by 2020?
400 Gbps to 1 Tbps per optical link
What is a common connection type for small or medium-sized businesses to the Internet?
Ethernet LAN configuration
Fill in the blank: Mobile devices connect to the Internet through the _______.
public cellular network
What are the main components of an ISP network?
- Interconnected routers
- High-speed links to the Internet
What are some design issues related to telecommunications links?
- Signal encoding
- Error control
