6 Comms Flashcards
WAN
Country or world
Metropolitan area network
City or suburb
Local area network
Office, building
Client-server LAN
Clients use server
Allows users to share files and programs
Peer to peer LAN
No server
Less secure
Less stable
Node
Any device attached to network -
Printers included
Packets
Fixed-length block of data for transmission
1000 bytes
Protocols
A set of conventions governing the exchange of data between hardware and software components in a network
Switch
A device that connects computers to a network and facilitates communication by sending messages between send and receiver nodes
Bridge
An interface used to connect two similar networks
Gateway
An interface permitting communication between dissimilar networks
Router
Specialized devices for transmitting data, physical devices that join multiple networks
Backbone
The main highway - including gateways, routers - that connects all computer networks in an organization
Topology
Layout of a network
Star network
All computers and directly connected to a central network switch
Phone networks
Ring network
All microcomputers are connected in continuous loop
If one stops working…
Flows one way
Bus network
All nodes are connected to a single wire or cable.
Two endpoints, or terminators, which stop the network signal.
Each comms device on the network transmits electronic messages to other devices
Messages can collide without special software and hardware
Limited to 20 devices on 185 m cable
If one removed…
Tree network
Bus network of star networks
University departments linked by main bus
Mesh network
Each node has more than one connection to the other nodes
A message can take any possible shortest route
Internet
Twisted-par wire
Phone line
2 strands of insulated copper wire
Slowest, 128 megabits/sec
Coaxial cable
Insulated copper wire in metal shield and plastic
Cable TV and internet
Shielded
Fiber optic cable
Up to 2 billion pulses per second
Ethernet
Cat5
Requires cables, a few routers
Phone line network
HomePNA tech
320 megabits/sec
Power line
HomePlug
200 megabits/sec
Narrowband
For voice and phone
Broadband
1 gigabit/sec
Wireless application protocol
A standard designed to link all mobile devices to carrier’s wireless network
Wireless types
IR Broadcast radio Cell radio Micro radio (Bluetooth) Communications satellites
Satellites
Geo highest
Meo 10 000 miles
Leo 1000 miles
Generations
1 - analog cell 2 -digital cells and pdas 3 - smartphones 4 smarter phones LTE long term evolution
Short-range wireless
LAN - to 228 feet. Wi-fi
Personal area networks - to 33 ft. Bluetooth, wireless USB
Home automation networks - to 150 ft.
Wireless standards
- 11b home
- 11a business
- 11g over 54 mbps
- 11n over 600 mbs
WiMax
Worldwide interoperability for microwave access
Up to 30 miles. More than wifi
Ultra-wideband
Military radar
Smart home
Insteon
\zigbee
Z-wave
Trolls
Comments
Hackers
Script kiddies Hacktivists - Anonymous Black-hat hackers Cyberterrorists Benign hackers Benevolent hackes
Worm
Subclass of virus that copies itself repeatedly into computer’s memory
Rootkit
Secret program installed in OS so someone can take control
Zombie
Computer taken over covertly and programmed to respond to instructions sent remotely
Botnet
Robot network waiting for commands
Pharming
Malicious software in your computer redirects you to an impostor web page
Evil twin attack
Fake wifi hot spot that your computer thinks offers safe access to a secure public network and then monitors your communications and steals data you input
CERT
Computer emergency response team
USDDept
Tools for fighting online fraud
Rule-based detection software Predictive statistical model software Employee internet management software Internet filtering software Electronic surveillance
Prism
Uses online data from 9 companies - google, fb, apple about the online activity of customers
XKeyscore
Allows analysts to search with no authorization through dbs containing emails, chats, browsing histories
FISA court
Foreign intelligence surveillance act court,
Group of 11 judges responsible for making decisions about gvt surveillance in ns cases
Nsa
Gathers intell by targeting computers and comms of foreign entities
Protects nsa’s and military’s computers
Mines metadata
Privacy and civil liberties oversight board
No power
Tailored access operations unit
Harvests from overseas networks
Switch
Transfers data packets between 2 networks
Not a standard
802.11ac
RAID 0
Automatically duplicates your data and saves it on 2 identical drives
SDRAM
The most common type of RAM in current systems
Virus
Means same thing as worm
