Chapter 7 PowerPoint Flashcards
What are some of the benefits of computer networks
Education, research, medicine and more benefits.
Worldwide communications
Spread of information and data
Possibly a vehicle for spreading misinformation
Helps to equalize access to information
What is a computer network made up of
Computing devices and interconnections
What are the devices located on a computer network called
Nodes
T/F Networks are wired only
FALSE. Networks can be wired or wireless.
What are examples of wired networks
Dial up
Broadband (cable modems and DSL)`
What are examples of wireless networks
WLAN, WWAN, MAN, LAN, PAN
Describe dial-up telephone lines
Analog lines that transmit digital data.
What modulates the carrier wave in a dial up telephone line
Modem modulator
What is the max speed of a dial up connection
56 KBps
What is the bandwidth
The capacity
What is the transmission rate that broadband provides
A transmission rate of greater or equal to 25 Mbps
Describe the download/upload speeds of Home Internet Connections
Asymmetric download/upload speed
Describe DSL
Uses phone lines but sends digital signal on different frequencies than voice
What does DSL stand for
Digital Subscriber Line
What is the download rate range for a DSL connection
Between 5-50Mbps
What is the upload range for a DSL connection
Between 1-5Mbps
Describe Cable Modem
Uses cable TV lines
What is the download range for a cable modem
Up to approximately 100Mbps
What is the upload range for a cable modem
Between 3 to 5Mbps
What are three examples of commercial or institutional internet connections
Ethernet
Fast Ethernet
Gigabit Ethernet Standard
What was the common type of commercial or institutional internet connection in the 1970s
Ethernet
Describe Ethernet internet connections in a commercial environment
Dedicated coaxial cable
How fast does ethernet in a commercial environment run
Operates at 10Mbps
Describe Fast Ethernet internet connections in a commercial environments
Dedicated lines (coaxial, fiber-optic, twisted-pair copper wire)
How fast does fast ethernet internet connections in a commercial environment run
Operates at 100Mbps
Describe Gigabit Ethernet Standard internet connections in a commercial environment
From gigabit networking researching project.
IEEE standard
How fast does gigabit ethernet standard connection in a commercial environment run
Operates at 1000 Mbps
What does Wireless Data Communication allow for
Allows network communication without the need for cables holding you to one place
What are some examples of Wireless Data Communication
Radio, microwave or infrared signals to mobile computers
Is it true that mobile computing delivers data regardless of location
TRUE
Describe Bluetooth
Low power, close range (30-50 feet), connects devices like wireless mice, cameras, video games
What is the function of a WLAN
Computers transmit wirelessly to a base station which has a wired connection
What is the range of a WLAN network
Range of 150-300feet
What does WLAN stand for
Wireless Local Area Network
What does Wifi stand for
Standard term for wireless network communication
What is the IEEE 802.11
It is the wireless network standard
What are some examples of Wifi Hot Spots
Library, Campus, Coffee Shop, Etc
What is a metropolitan Area Network
A built-out wireless network that covers blocks or cities
What is a MAN
Metropolitan Area Network
What is the function of WWAN
Computers transmit wirelessly to a remote base station which has a wired connection. Cellular technology involves antennas on towers miles apart
What speed does 4G transmit at
50 to 500Mbps
What are some downsides to Wireless wide area network (WWAN)
- Signal may be blocked while indoors
- Errors with data transmission can slow performance
- Security concern: wireless signals are easy to intercept
What are the characteristics of LAN
Wired connections
Computers, printers, and servers are in close proximity. Privately owned and operated
What is topology
How computers are connected. Directly affects how they communicate
What is the bus topology
Shared Lines
Devices take turns using the line
What is the ring topology
Messages circulate until they reach the source
What is a star topology
All messages are sent to a central node, which routes messages to their destinations
Describe the properties of an ethernet LAN with a shared cable
Bus topology
Single cable over short distances
Multiple cables over longer distances
What is the function of a repeater
Amplifies the signal on a LAN
What is the function of a bridge
routes messages only when necessary
Describe the properties of an ethernet LAN with a switch
Bus topology
Shared cable is inside the switch
Wiring closet contains switch and ports
Ethernet jacks in rooms connect to the switch in the closet
Wireless base stations also connect to the switch in the closet
Describe the properties of a WAN
- Wired Connection
- Connected computers that are located at great distances
- Dedicated point to point lines
- Store and forward, packet switched
What does WAN stand for
Wide Area Network
What does “Dedicated point-to-point lines” mean
Computers connect to other computers on individual lines
What does “Store and Forward, packet switched” mean
Packets go from node to node until reaching their destination
How is the routing of packets in a WAN connection determined
Routing of packets is determined dynamically.
What are the benefits of using a WAN connection
Redundant paths,
fault tolerance,
responsive to traffic load
Describe the general overall structure of the internet
Combination of LANs and WANs.
Connected by routers that direct message traffic
What does ISP stand for
Internet service provider
What is the function of an ISP
an ISP provides access to the Internet for private individuals and organizations.
What does DNS stand for
Domain name services
What is the function of a DNS
Domain name services provide addressing information.
What are the levels that ISPs exist at
Local, regional, national and international
What is a protocol
A standard set of rules for communicating
What is protocol hierarchy/protocol stack and TCP/IP
Layers of protocols
Physical transmission to end application rules and standards
What group makes standards in terms of communication protocols
The Internet Society makes standards and promotes research.
What type of agreement makes the internet possible (very general answer)
International agreements
What is the name of the 5th layer of the communication protocol?
Application
What are some examples of the 5th layer of the communication protocol
HTTP,SMTP,FTP
What is the name of the 4th layer of the communication protocol?
Transport
What are some examples of the 4th layer of the communication protocol?
TCP,UDP
What is the name of the 3rd layer of the communication protocol?
Network
What are some examples of the 3rd layer of the communication protocol?
IP
What is the name of the 2B layer of the communication protocol?
Logical Link Control
What are some examples of the 2B layer of the communication protocol?
PPP, Ethernet
What is the name of the 2A layer of the communication protocol?
Medium Access Control
What are some examples of the 2A layer of the communication protocol
Ethernet
What is the more common name for the 2B and 2A layer of the communication protocol
DATA LINK LAYER
What is the name of the 1st layer of the Communication protocol
Physical
What are some examples of the 1st layer of the communication protocol
Modem, DSL, Cable Modem, WiFi, 4G
What are the points of consideration for the physical layer protocols
- How to know when a bit is present on the line
- How much time the bit will remain on the line
- Whether the bit is digital or analog in form
- What physical quantities represent 0 and 1
- Shape of the connector between the computer and the transmission line
What is a general definition of the physical layer protocols
Rules for exchanging binary data across a physical channel (fibre-optic, twisted pair, wireless, ETC)
What is the purpose of the Data Link protocols
Ensure reliable transmission of bits
Error detection and correction notices failures in the transmission and fixes them.
Framing determines which bits belong to one message.
What are the two major features of Data Link Protocols
Error detection and correction notices failures in the transmission and fixes them.
Framing determines which bits belong to one message.
What are the two components of the data link protocols
Layer 2a: Medium Access Control
Layer 2b: Logical Link Control
What is the function of Medium Access Control Protocols
Rules for communicating on shared lines - who has ownership.
Describe the contention-based protocol used in medium access control
When a node wants to send a message
Listen to the line and wait until it is free
Begin transmitting as soon as it is free
If a collision results, wait a random amount of time
Repeat
What is the advantage to medium access control protocols
Distributed, no master bottleneck
What is the function of Logical Link Control protocols
Rules for detecting and correcting errors
What does ARQ stand for
Automatic Repeat Request
What does ACK stand for
Acknowledgement message
Describe the ARQ algorithm on the Senders SIDE
Transmit a packet and wait for ACK or time out
If ACK received, go on to next packet
Otherwise, repeat on the current packet
Describe the ARQ algorithm on the receivers side
If no error, return acknowledgement message (ACK)
Otherwise, return nothing
What does a package sent by the Data Link Protocols contain
Markers for start and end of packet (SOP and EOP)
Sequence number for packet (e.g., 2 of 5)
Packet data
Error-checking bits
What is the purpose of the Data Link Layer
Create a virtual error-free message pipe
Messages go in one end
Come out the other correct and in the right order
What is the purpose of the Network Layer Protocols
Transmit messages across multiple nodes in a network
Good faith transmission model
What are the requirements for the network layer protocols
Standard for addressing all network nodes
Routing method for finding a route from any node to any other node
Describe the Host Name in relation to addressing (network layer of communication protocol)
human-friendly name for a node
Describe the IP Address in relation to addressing (network layer of communication protocol)
Unique numerical address used by the computer
Describe the DNS in relation to addressing (network layer of communication protocol)
Maps host names to IP addresses
How does a computer retrieve the DNS for a host name
Symbolic host name goes to a local DNS server
If it has no record, goes to remote servers until one has the host name and retrieves the IP address
What is the function of routing in the network layer of the communication protocol
Picking a path through the network from source to destination
Seeks the shortest/best path: fastest travel
Massive network requires efficient path-seeking
Networks are dynamic: nodes come online and go offline all the time—routing must adapt quickly
Describe Transport layer protocols
Application to application, reliable packet delivery
What is a port number
Unique identifier for a program
What is the standard port number for a web server
80
What is the standard port number for a Domain Name Service
42
What is the standard port number for a SMTP, Sending Email
25
Why is TCP used
- Ensures no errors
- Establishes ordered delivery of packets
- Another version of ARQ algorithm
- Virtual direct, quality connection between programs
What does TCP stand for
Transport Control Protocol
What is the function of Application layer protocols
Handle formatted data transmitted between application programs
What does HTTP stand for. What port is it associated with
Hypertext Transfer Protocol. Port 80
What does SMTP stand for. What port is it associated with
Simple Mail Transfer PRotocol.
Port 25
What does POP3 stand for. What port is it associated with
Post Office Protocol. Port 110
What does IMAP stand for. What port is it associated with
Internet Message Access Protocol. Port 143
What does FTP stand for. What port is it associated with
File transfer protocol. Port 21
What does TELNET stand for. What port is it associated with
Terminal Emulation Protocol. Port 23
What does DNS stand for. What port is it associated with
Domain Name System. Port 42
What application is HTTP associated with
Accessing Webpages
What application is SMTP associated with
Sending Email
What application is POP3 associated with
Receiving email
What application is IMAP associated with
Receiving email
What application is FTP associated with
Accessing Remote Files
What application is TELNET associated with
Accessing Remote Terminals
What application is DNS associated with
Translating symbolic host names to IP addresses
What does URL stand for
Uniform Resource Locator
How is a web page identified with HTTP
Web page or service is identified by a unique URL
What does a web browser use to send formatted messages to a web server (and vice versa)
Web browser uses TCP
What aspects of the communication protocol are used within TCP
Network layer, Data link Layer and physical layer
What is the process involved with the application layer (using HTTP)
Browser reads protocol, extracts host name (and requests IP address from the DNS server)
Sends a connect message to port 80 on that machine
After connection is established, sends “Get” message with page information
Server responds with message containing page contents and size and indicates the connection closes at the end of the message
What are three examples of interpersonal communications
Electronic Mail
Bulletin Board System
Instant Messaging / Texting
What is Electronic mail
A message read at the recipient’s convenience. Fast, multimedia, broadcast medium.
What is Bulletin board system
Public forum for shared communications.
Evolved into internet forums and chat rooms
What does email stand for
electronic mail
What does BBS stand for
bulletin board system
What are some benefits of social networking
Fast communication with people around the globe
The potential for rich discussion around a topic
A public forum where many people can contribute
What are the disadvantages
to social networking
Anything posted online can follow you forever
Cyberbullying
Potential invasion of privacy
On a network, what service do print servers provide
They serve all computers with printing possibilities on a LAN
On a network, what services do file servers provide
They provide storage to all users
On a network, what service does client/server computing provide
Some nodes provide services and other nodes use those services
On a network, what service do distributed databases and data warehouses provide
Massive data stored in various sites online
On a network, what does groupware or a wiki provide
Support collaborative knowledge or data construction
What functions did early applications of ecommerce provide
Automatic pay check deposit
ATMS
Checkout Scanners and Inventory Systems
What functions do the current applications of ecommerce provide
Online Stores
Electronic Bill Payment
Online Payment Systems
Individual Sales to the World
What percent of all retail sales are performed online
8%
What are three examples of cloud services
Infrastructure
Application
Platform and Development
What is virtualization
Separation of a service from the entity providing it.
What are some benefits to cloud computing
Nodes are local, server is off site.
Greatly reduced costs
Virtualization
What can a cloud server be a part of
An integrated server farm
What does internetworking
Standards for communication
What is a gateway device
A device for translating between networks
What network was present in 1962
Licklider’s “Galactic Network”
What network was present in 1966
ARPA-funded ARPANET
What network was present in 1972
What network was present in the 1970s/1980s
Many networks such as HEPNET and DECNet
Describe the middle years of the world wide web
TCP/IP was the established standard
Telnet, FTP
When was NSFNET introduced
1984
Who was eligible to use ARPANET
Only open to ARPA grant recipients
Who was eligible to use NSFNet
Open to universities, government agencies, libraries, museums and school
When did networks begin to connect
In the late 1980s
When was NSFNet turned over to private providers
in 1995
What is hypertext and how did it lay the foundation for modern day webpages
documents containing links to other documents became the foundation for modern-day webpages
What ultimately led to the rapid expansion of the world wide web
When web protocols were made public
