Computer Science Chapter 4: Networking and the Internet
Unlock all answers in this set
Unlock answersquestion
networks
answer
linked computer systems
question
local area network (LAN)
answer
univeristy campus, house
question
Metroploitan Area network (MAN)
answer
...
question
Wide area network (WAN)
answer
...
question
proprietary
answer
closed or private network
question
access points
answer
focal points around which all communication is coordinated
question
hub
answer
connects computers to a central location through running links and bus networks
question
protocols
answer
established rules in which activites are conducted
question
Carrier Sense, Multiple Access with Collision Detection
answer
protocol that controls the right to transmit messages dictates that each message be broadcast to all the machines on the bus. each machine monitors all the messages but keeps only those addressed to itself.
question
hidden terminal problem
answer
signals from the different machines are blocked from each other by objects or distance even though they can all communicate with the central AP.
question
Carier Sense, Multiple Access with Collision Avoidance
answer
designed to avoid collisions and may not eliminate them completely when collisions do occur the messages must be retransmitted.
question
repeater
answer
a device that simply passes signals back and forth between the two original buses without considering the meaning of the signals
question
bridge
answer
more complex than a repeater connects two busses, and looks at the destination address that accompanies each message and forwards a message across the connection only when that message is destined for a computer on the other side.
question
switch
answer
is essentially a bridge with multiple connections, allowing it to connect several buses rather than just two. produces a network consisting of several buses extending from the with as spokes on a wheel
question
internet
answer
a network of networks the original networks maintain their individuality and continue to function as autonomous networks
question
routers
answer
connection between networks to form an internet special purpose computers used for forwarding messages
question
forwarding table
answer
contains router's knowledge about the direction in which messages should be sent depending on their destination addresses.
question
gateway
answer
the point at which one network is linked to an internet serves as a passageway between the network and the outside world.
question
interprocess communication
answer
communication between processes
question
client/server
answer
defines the basic roles played by the processes
question
client
answer
makes requests of other processes
question
server
answer
satisfies the requests made by clients
question
peer to peer model
answer
involves processes that provide service to and recieve service from each other involves processes on a temporary basis
question
distributed systems
answer
meaning that they consist of software units that execute as process on different computers
question
cluster computing
answer
describes a distributed system in which many independent computers work closely together to provide computation or services comparable to a much larger machine
question
high-availablity
answer
because it is more likely that at least one member of the cluster will be able to answer a request, even if other cluster members break down or are unabailable
question
load-blancing
answer
the workload can be shifted automatically from members of the cluster that have too much to do to those that may have too little
question
grid computing
answer
refers to distributed systems that are more loosely coupled that clusters but that still work together to accomplish large tasks can involve specialized software to make it easier to distribute data and algorithms to the machines participating in a grid.
question
cloud computing
answer
google cloud space can switch huge pools of shared computers on the networks can be allocated for use by clients as needed.
question
Internet
answer
originated from research projects going back to the early 1960s
question
Internet Service Providers (ISP)
answer
organizations that maintain and constructs these networks.
question
intranet
answer
independent internet operated by a single authority that is in the business of supplying internet access to individual users
question
end systems
answer
devices that indicidual users connect to the access ISP not necessarily computers in a traditional sense
question
hot spot
answer
area within the AP's range.
question
modems
answer
convert digital data to be transferred into a form compatible with the transmission medium being used
question
dial-up
answer
used for temporary connections in which the user places a traditional telephone call to an access ISP's router
question
IP addresses
answer
"internet protocol" unique identifying address to each computer in the system
question
Internet Corporation for ssigned Name and Number (ICANN)
answer
a nonprofit corporation established to coordinate the internets operation
question
dotted decimal notation
answer
the bytes of the adderess are separated by periods and each byte is expressed as an integer represented in traditional base ten notation
question
domain
answer
a "region" of the internet operated by a single, authority such as a university, club, company, or government agency
question
registrars
answer
handles the process of registering each domain
question
domain name
answer
mnemonic name that is unique among all the domain names throughout the internet.
question
subdomains
answer
used as a means of organizing the names within a domain
question
domain name system (DNS)
answer
names servers are used as an internet-wide directory
question
DNS lookup
answer
process of using the DNS to perform a translation
question
email
answer
a system by which messages are transferred among internet unsets
question
mail server
answer
established within domains operated by access ISPs for the purpose of providing mail service to users within its realm
question
Simple Mail Transfer Protocol (SMTP)
answer
initially designed for transferring text messages encoded with ASCII
question
Multipurpose Internet Mail Extensions (MIME)
answer
developed to convert non ASCII data to SMTP compatible form
question
Post Office Protocol version 3(POP3)
answer
user transfers messages to his or her local computer where they can be read, stored in various folders, edited and otherwise manipulated as the user desires
question
Internet Mail Access Protocol
answer
allows a user to store and manipulate messages and related materials on the same machine as the mail server
question
File Transfer Protocol (FTP)
answer
a client/sever protocol for transferring files across the internet to transfer a file using this method a user at one compute in the internet uses a software package that implements ftp to establish contact with another computer.
question
telnet
answer
protocol system that was established to allow computer users to access computers from great distances a user can contact the telnet server at a distant computer then follow that operatings systems login procedure to gain access to the distant machine
question
secure shell (SSH)
answer
alternative to telnet that offers a solution to an eavesdropper intercepting a pssword and later misuing the information. provides encryption of data being transferred as well as authentication
question
VoIP (voice over Internet Protocol)
answer
the internet infastructure is used to provide voice communication similar to that of traditional telephone systems
question
soft phones
answer
P2P software that allows 2 or more PCs to share a call with no more special hardware than a speaker and a microphone i.e. skype
question
analog telephone adapters
answer
VoIP devices that allow a user to connect his/her traditional telephone to phone service provided by an access ISP
question
N-unicast
answer
a single sender involved with multiple unicasts
question
multicast
answer
transfers the distribution problem to the internet routers
question
hypertext
answer
text documents, images, video, and audio that contains links
question
World Wide Web(www)
answer
the web that has evolved on the internet
question
website
answer
a collection of closely related webpages
question
HTTP
answer
hypertext transfer protocol transfer between browsers and web servers
question
url
answer
uniform resource locator contains information needed by a browser to contact the proper server and requested desired documents
question
tags
answer
special symbols that describe how the document should appear on the display screen, what multimedia resources and which items are linked to others
question
HTML
answer
hypertext markup language system of tags
question
search engine
answer
websites that assist users in locating web material pertaining to a subject of internet
question
client-side activities
answer
browser
question
server-side activities
answer
web server
question
web mail
answer
access email by web browser
question
XML
answer
extensible mark up language standardized style for designing notational systems for representing data as text files
question
markup languages
answer
developed for representing math, and multimedia presentations and music
question
source
answer
HTML encoded version
question
application layer
answer
message originates here software units such as clients and servers that use internet communicatioin to carry out their tasks not restricted to software in application classification
question
transport layer
answer
accept messages from the application layer ensure the messages are properly formatter for transmission over the internet divides long messages into small segments which are transmitted over the internet as individual units adds sequence numbers to the small segments it produces so that the segments can be reassembled at the messages destination
question
network layers
answer
decides which direction a packet should be sent at each step along the packet's path through the internet in charge of maintaining the router's forwarding table and using that table to determine the direction in which to forward packets
question
link layer
answer
responsibly for transferring the packet deals with the communication details particular to the individual network in which the computer resides
question
packet
answer
small segments of long messages that is transported through the application, transport, network, and link layers.
question
Open System Interconnection (OSI)
answer
standard based on a seven-level heirarchy as opposed to the four-level hierarchy carries the authority of an international organization, but it has been slow to replace the four-level point of view
question
Transmission Control Protocol (TCP)
answer
a version of the transport layer. provides more than one way of implementing the transport layer
question
User Datagram Protocol (UDP)
answer
does not offer retransmission services and said to be unreliable protocol sends the message to the address it was given and forgets about it. connectionless protocol
question
flow control
answer
TCP transport layer at a message's origin can reduce the rate at which it transmits segments to keep from overwhelming its counterpart at the destination
question
congestion control
answer
a TCP transport layer at a message's origin can adjust its transmission rate to alleviate congestion between it and the message's destination
question
forwarding
answer
relaying packets through the internet
question
routing
answer
updating the layers forwarding table to reflect changing conditions
question
hop count
answer
value is a limit to the number of times the packet should be forwarded as it tries to find its way through the internet
question
malware
answer
malicious software software can be transferred to, executed on, the computer itself, or it might attack the computer from a distance
question
virus
answer
software that infects a computer by inserting itself into programs that already reside in the machine when the host program is executed the virus is also executed some may perform devastating actions such as degrading portions of the operating systme, erasing lare blocks of mass storge, or corrupting data ad o programs
question
worm
answer
autonomous program that transfers itself through a network, taking up residence in computers and forwarding copies of itself to other computers
question
what is a characteristic consequence of a worm?
answer
an explosion of the worms replicted copies that degrades the performance of legitimate applications and can ultimately overlaod an entire network or internet
question
Trojan horse
answer
a program that enters a computer system disguised as a desirable program such as a game or useful utility package that is willingly imported by the victim typically arrive in the form of attachments to enticing emal messages
question
spyware
answer
software that collects information about activities at the computer on which it resides and reports that information back to the instigator of the attack used for recording the symbol sequences typed at the computers keyboard in earch of passwords or credit crd numbers
question
phishing
answer
a technique of obtaining information explicitly by simply asking for it play on word for fishing becuase the prcess involved is to cast numerous lines in hopes that someone will take the bait often carried out via email and in this form it is little more tan an old telephone con
question
denial of service (DoS)
answer
the process of overloading a computer with message
question
spam
answer
abundance of unwanted messages is the proliferation of unwanted junk email effect of spam is to overwhelm the person receiving the spam
question
firewall
answer
filter traffic passing through a point in the network may be installed at the gateway of an organizations intranet to filter messages passing in and out of the region
question
spoofing
answer
saying you are someone you are not
question
spam filters
answer
firewalls designed to block unwanted email
question
proxy server
answer
software unit that acts as an intermediary between a client and a server with the goal of shielding the client from adverse actions of the server
question
antivirus software
answer
used to detect and remove the presence of known viruses and other infections
question
FTPS
answer
a secure version of FTP, and SSH
question
HTTPS
answer
secure version of HTTP used by most financial institutions to provide customers with secure internet access to their accounts
question
Secure Sockets Layer (SSL)
answer
backbone of HTTPS originally devleoped by netscape to provide secure communication links between web clients and servers
question
public-key encryption
answer
incolves techniques by which encryption sysstems are designed so that having knowledge about how messages are encrypted does not allow one to decrypt messages
question
keys
answer
two values that are used in the public-key encryption system
question
public key
answer
used to encrypt messages
question
private key
answer
required to decrypt messages
question
certificate authorities
answer
maintains an accurate list of parties an their public keys, they then act as servers provide reliable public-key informationto their clients in packages known as certificates
question
certificate
answer
package containing a partys name and that partys public key
question
authentication
answer
making sure that the author of a message is in fact the party that it claims to be
question
digital signature
answer
a bit pattern producesd by the holder of the private key
