Module five day two Flashcards
Why would I use non-routable space for internal IP addresses
IP addresses are scarce and expensive, non-routable space is secure.
NAT
Network address translation. A way to map many private addresses inside a local network to a public IP address Before trans frame the information onto the internet
who uses nat?
organizations that won multiple devices to employ single IP address, and most home routers.
What makes network configuration easier?
configuring local DNS and DHCP server
Is non-routable address space intended to access the internte?
no, unless you use Network Address Translation to translate non-routable IP addresses to public ones, allowing them to access the internet.
what network layer does NAT operate at?
3, the Network layer.
What reserves an alias IP address for a device in routable range?
NAT
What allows a private network to connect with the internet through the translated public IP?
NAT
WAN
Acts like a single network, but spans across multiple physical locations
What do WAN usually require?
I contract a link across the internet with my internet service provider
What handles sending data from one site to another?
ISP
Where does each LAN network end?
a demarcation point where the ISP network takes over.
what is the area between each demarcation point and an ISPs actual core network?
local loop
What is an example of a local loop?
something like a T carrier line, high speed optical connection to the provider’s regional office.
What would connect to the ISP’s core network and the internet at large?
WAN
What is a physical Connection that leaks a customer’s premises to a telecommunication service providers network?
local loop, local tale, subscriber line, last mile
How do WAN work?
busing different protocols at the data link layer to transport data from one site to another.
WAN protocols are sometimes at work
at the core of the internet itself.
What can be connected Through the internet with connections provided by internet service providers in each locale?
WAN
What can be formed by connecting multiple LAN sites using equipment and cables leased from a regional internet service provider?
WAN
what can be configured through virtual private networks
security for WAN across the public internet
what are hardware devices that act as intermediate systems to route data amongst the LAN member groups of a WAN using a private connection? they also facilitate and organization’s access to a carrier network. they also have a digital modem interface for the WAN, which works at the OsI link layer, and an ethernet interface for the LAN
WAN router, border router, edge router.
what is software developed to address the unique needs of cloud based WAN environments? they can be used alone or in conjunction with a traditional WAN, simplify how WAN are implemented, managed, maintained. the overall cost to operate them is less than the overall cost of equipping and maintaining a traditional WAN.
SD-WAN, software defined WAN.
Why do SD-WAN replace lines leased from an internet service provider by linking regional LAN together to build a WAN?
to reduce operational costs
what are four techniques available to optimize network traffic and data storage on a WAN?
compression, deduplication, protocol optimization, local caching, traffic shaping
what technique involves reducing file size to improve network traffic efficiency? it has algorithms available for text, image, video, etc. also the center and receiver will need apps that offer the same algorithm to encode and decode files.
compression
what technique prevents files from being stored multiple times within a network to avoid wasting expensive hard drive space? one copy of a file is kept in a central location and all other copies are file pointers to the single copy of the file, n which saves hard drive space, makes performing data backup efficient, reduces the amount of time to recover data from data lost disasters
deduplication
what technique improves the efficiency of network protocols for applications that need higher bandwidth low latency
protocol optimization
what are three techniques in traffic shaping
bandwidths throttling, rate limiting, use of complex algorithms
what technique on a WAN stores local copies of network and internet files on a usual computer to reduce the need to resend the same information across the network every time the file is accessed?
local cashing
what’s an example of local caching
WAN optimization products storing shared files at a physical LAN location when groups of employees at the location tend to request the same set of files frequently.
what technique involves optimizing network performance by controlling the flow of network traffic?
traffic shaping
what traffic shaping technique involves controlling network traffic volume during peak use times?
throttling bandwidth
what traffic shaping technique involves capping maximum data rates and speeds
rate limiting
what traffic shaping technique involves classifying and prioritizing data to give preference to more important traffic?
use of complex algorithms
would are used in conjunction with WAN routers to perform the task of distinguishing between a private LAN and the related public WAN?
WAN protocols
what are examples of WAN protocols and techniques?
packet switching, frame relay, asynchronous transfer mode (ATM), high level data control HLDC), packet over synchronous optical network (SONET) or synchronous digital hierarchy (SDH), multi protocol label switching (MPLS)
what method of data transmission involves breaking messages down into multiple packets? with each packet having a header that includes information on how to reassemble the packet as well as the intended destination of the packets.
Packet switching
in packet switching, why are packets triplicated?
to prevent data corruption
what is done with triplicated packets?
they are sent separately over optimal routes, then reassembled when they reach their destination.
what happens to triplicated copies of a packet when they reach their destination
they are reassembles and the copies are compared with each other to detect and correct data corruption. at least to of the three copy should match.
what happens of the data from packet switching cannot be reassembled or data corruption is evident in all three copies?
the destination makes a request to the origin to resend the packet
Which method of data transmission is an older technology originally designed for use and integrated services digital network lines?
Frame Relay
which method of data transmission is no used transmitting data between end points of WAN through a pocket switching method that works at the OSI data link and physical layers?
Frame Relay
what data communications network is used to transport data packets and frames, with the reliability minimizing the need for error checking?
a frame relay network
in frame relay what circuits are used for long term data connections and stay open even when data are not being transmitted
permanent virtual circuits
in frame relay what circuits are used in temporary session connections for sporadic communications
switched virtual circuits
put etc the frames and frame relay include?
routing address information for the destination
what is an older technology that encodes data using asynchronous time division multiplexing?
asynchronous transfer mode, ATM.
in asynchronous transfer mode how is data sent?
encoded data is packaged into small fix size cells. it can be sent over long distances which makes it useful for WAN communication.
how does ATM use routers?
as end points between ATM networks and other networks
what has ATM technology been replaced by?
internet protocol, IP
what WAN protocol involves the encapsulation or data link protocol that delivers data frames through a network, with frames including multiple fields that can hold information about start and end flags, controls, frames check sequence, and protocol use?
HLDC, High Level Data Control
What was developed to use multiple protocols to replace SLDC, Synchronous Data Link control?
HLDC
What protocol includes error correction, flow control, and data transmission through polling?
HLDC
What protocol has three modes to define the relationship between two devices, or nodes, during communications?
HLDC
What are the three modes of the HLDC protocol?
Normal response mode, asynchronous response mode, asynchronous balanced mode.
in high level data control, what is a normal response mode?
primary node must give permission to the secondary node to transmit
in high level data control, what is asynchronous response mode
the primary node allows the secondary node to initiate communication
what is asynchronist balanced mode in high level data control
both nodes can act as etc the primary or secondary nodes. they can initiate communications without permission.
what communication protocol is used for WAN transport, defining how point to point links communicate over fiber optics?
Packet over synchronous obstacle network (SONET) or synchronous digital hierarchy (SDH)
what technique for optimizing network routing replaces inefficient table lookups for long network addresses with short path labels, with labels directing data from node to node?
n multi protocol label switching MPLS
What are a popular alternative to WAN technologies
point to point vpn
Where a WAN technologies best?
when you need to transport large amounts of dataAcross lots of sites.
WAN technologies are built to be
superfast
Business cable or direct service line dsl maybe cheaper, but
it can’t handle the load required when you need to transport large amounts of data across lots of sits
what lets companies outsource all or part of their different pieces of infrastructure to other companies to manage?
the cloud
what typically hosts emails these days?
the cloud
what can a company do with their email?
they can have a cloud hosting provider host the email server, or even use an email as a service provider.
what do lots of businesses no longer require between their sites?
extreme high speed connections, WAN expense
what does a point A point VPN do
make sure different sites of a company can communicate with each other, by establishing a VPN tunnel between them.
for site to site VPN, what handles the tunneling logic?
network devices at either side
What does WAN stand for
wide area network
In a WAN what is the area between a demarcation point and the internet service provider’s core network known as
local loop
A point to point virtual private network is also known as
site to site virtual private network vpn
Who handles sending data from one site to another
internet service provider
In today’s world what are fewer devices weighed down by
physical cables
what type of networking is on the rise?
wireless networking
Where are the most common specifications for how wireless networking devices should communicate defined by?
the IEEE 802.11 standards.
what set of specifications makes up the set of technologies we call wifi?
801.11
how do wireless networking devices communicate with each other?
radio waves
what is a frequency band?
a certain section of the radio spectrum that’s been agreed upon to be used for certain communications. different 802.11 standards generally use the same basic protocol, but might operate at different frequency bands.
what is the range of FM radio broadcast band in north America?
between 88 and 108 megahertz
what frequencies do wifi networks most commonly operate on
2.4 gigahertz and 5 gigahertz bands.
what are the most common 802.11 specifications? in the order that they were adopted
802.11b, 802.11a, 802.11g, 802.11n, 802.11ac
what are improvements each new version of the 802.11 specifications have seen?
higher axes speeds, ability for more devices to use the network simultaneously
what define how we operate at both the physical and data link layers in Wifi?
802.11 protocols
List the fields in an 802.11 frame
frame control 2octets, duration/ID 2 octets, address 1 6 octets, address 2 6 octets, address 3 6 octets, sequence control 2 octets, address 4 6 octets, data payload 0-7951 octets, FCS 4 octets
Which field in a 802.11 frame its 16 bit long and contains a number of subfields that are used to describe how the frame itself should be processed? For example: what version of 802.11 was used.
frame control field
what 802.11 field specifics how long the total frame is so the receiver knows how long it should expect to have to listen to this transmission
Duration field
How many address fields are there in 802.11?
four
what’s a device that bridges the wireless and wired portions of a network
Wireless access points
important for the wireless device to talk to specific access points, Allows for incoming transmissions to the wireless device to be sent by the right access point
Associations
Why are there for address fields in 802.11?
there needs to be room to indicate which wireless access point should be processing the frame
Which wireless access point do devices on a wireless network associated with?
the one that they are closest to, Which has the best general signal strength, least wireless interference,
What is address one in 802.11?
source address field. The mac address of the sending device.
What is address 2 in 802.11?
intended destination on the network.
What is address 3 on 802.11?
receiver address. the mac address of the access point that should receive the frame.
What is address 4 on 802.11?
Transmitter address. The mac address of whatever has just transmitted the frame
What addresses might be the same in 802.11?
destination an receiver address, Source and transmitter.
What kind of addresses are all addresses in 802.11 frames?
mac addresses
What field is in between the third and fourth address fields in 802.11?
Sequence control field
What field in 802.11 is 16 bit long and mainly contains a sequence number used to keep track of the ordering of frames?
sequence control field
What field in 802.11 has all the data of the protocols further up the stack
data payload
Which frame on 802.11 contains a checksum used for a cyclical redundancy check like how ethernet does
frame check sequence field
What is wifi 6 formerly known as?
802.11ax
what are the benefits of wifi 6?
faster, more efficient for networks with a larger number of connected devices, higher data rates, increased band capacity, better performance, improved power efficiency.
how does wifi 6 get higher data rates
band splitting or increased client group sizes allow for uploading and downloading greater amounts of data
how does wifi 6 get increased band capacity?
band utilization is increased from eighty megahertz to one hundred sixty megahertz, creating a faster connection from the router to connected devices
how does wifi 6 get better performance?
input slash output streams are doubled from the four by four allowed by wifi 5 to eight by eight in wifi 6, allowing more clients to be grouped
how does wifi number six get improved power efficiency
devices only connect to the network when sending or receiving data increasing battery life.
what are some capabilities of wifi 6
channel sharing, target wake time, multiuser multiple input multiple output(MIMO), 160 MHz channel utilization, 1024 quadrature amplitude modulation, orthogonal frequency division multiple access (OFDMA), transit beam forming
what wifi 6 capability allows for better efficiency and shortened the time it takes to send data once a user gives the send command?
channel sharing
what wifi six capability improves the network speed and increases battery life by allowing battery powered devices to sleep when not in use
target wake time TWT.
what capability of wifi number six allows more data to be transferred simultaneously, increasing capacity and efficiency and high bandwidth applications like voice calls or video streaming
multiuser MIMO ( multiple inputs, multiple output) wireless technology
what capability of wifi 6 gives more space for transmitting data and increases bandwidth capability
160 MHz channel utilization
what capability of wifi 6 combines two signals into a single channel so more data is encoded
1024 quadrature amplitude modulation
what capability of wifi 6 allows for bandwidth splitting which is assigned dynamically by the axis point to separate devices?
orthogonal frequency division multiple access OFDMA
what wifi 6 capability is a technique that sends signals that allow for more efficient higher data rates by targeting each connected device
transmit beamforming
what does WiFi 6E extend wifi number six into?
6GHZ
What does Wi-Fi 6E have more of than 6?
channels to broadcast. 14 more 80MHz channels, 7 more 160MHz channels. allowing networks with it to have better performance even with high def video or VR.
how does wifi 6 improve the quality of networks
faster speeds and energy saving technology
What is an additional certification of wifi 6 that has even faster speeds and stronger performance?
Wi-Fi 6E
which wireless technologies use frequencies ranging from radio to microwave bands?
Wi-fi, z-wave, zigbee, thread, Bluetooth, near field communication.
what frequency bands have specific ranges that are divided into channels
radio and microwave
what band ranges does wifi use for sending and deceiving data?
2.4 GHz and 5 GHz
What do some wifi routers use to avoid signal interference and to load balance network traffic?
multiple channels within each range
what are some advantages of using 2.4GHz frequency bands?
- has the longest signal range from 150 feet (45 meters) indoors to 300 feet (92 meters) outdoors
- can pass through walls and other solid objects
what are disadvantages of using 2.4 gigahertz frequency bandwidths?
the long signal range also increases the chances of wifi traffic being intercepted by cybercriminals
* includes a limited number of channels that can range from 11 to 14 channels depending on regulations in the country of use
* can experience network traffic congestion and interference with other wifi networks and wireless technologies such as Bluetooth that overlap the frequency bands
microwave ovens also work in the frequency bandon can cause wifi interference
* under specific conditions the maximum achievable data rate is 600 Mbps
what are advantages of using 5 gigahertz frequency bandwidth
includes significantly more channels than 2.4 GHz
* experiences fewer interference problems and less wireless traffic congestion
can achieve over 2 Gbps data transfer speeds under specific conditions
disadvantages of using 5 GHz
the wireless range is limited to 50 feet (12 meters) indoors and 100 feet (30 meters) outdoors
does not penetrate wells and other solid objects as well as 2.4 GHz
when did the institute of electrical and electronics engineers ratify the first 802.11 standard for wireless fidelity?
1997
who is the standard for wireless fidelity first published for use by?
computer device manufacturers to uses a common protocol for wireless communications
how does the IEEE name each new amendment to wifi?
with one or two letters appended to 802.11.
how long does the institute of electrical and electronics engineers plan to continue updating the 802.11 specifications/
until a new technology replaces wifi
what do wifi networks include?
client devices that are configured to connect to wireless access points
what is the configuration of client devices to connect to wireless access points referred to as?
infrastructure mode
how do access points work between wireless devices and a wired network?
they can connect to an ethernet switch through a wired ethernet cable to bridge them.
what are some characteristics that may vary at the OSI physical layer for the various amended 802.11 specifications that mostly use the same fundamental data length protocol?
- signal ranges
- modulation techniques
- transmission bit rates
- frequency bands
- channels
what technology is required to prevent 5GHz wifi signals from interfering with local radar and satellite communication?
DFS, dynamic frequency selection
What are two common data protocol models that illustrate how low power internet of things devices share data
- request/ response model
- publish/ subscribe model
what protocol model is often used in distributed systems where the communication flow between servers and clients consists of requests and responses for data? examples include HTTP and CoAP
request/ response model
what protocol model is a framework for message exchanges between publishers and subscribers that I routed through a broker? subscribers can sign up to a channel to receive notices through the broker when the publisher releases new messages. examples: MQTT and AMQP
Publish/Subscribe Model
what can internet of things devices collect environmental data around?
physical location, equipment data, metered data
what’s an example of physical location data collected by internet of things devices
temperature
what’s an example of equipment data collected by internet of things devices
maintenance status
what’s an example of metered data collected by internet of things devices
electricity usage
what is needed to transfer and format the data for use by applications that interface with humans or automated systems? IoT
data protocols
what can we do with internet of things devices to facilitate the transfer and format of environmental data?
we can configure them to use various data transfer and formatting protocols at the application and software layers of communication OSI model wise.
what dater transfer protocols can most internet of things devices use at least one of
- hypertext transfer protocol/ secure (http/https)
- machine to machine communication protocols (M2M)
- message queue telemetry transport (MQTT)
- constrained application protocol (CoAP)
- advance message queuing protocol (AMQP)
- extensible messaging and presence protocol (XMPP)
- data distribution service (DDS)
what are the most widely used information transfer protocols across the worldwide web?
HTTP/HTTPS. hypertext transfer protocol / secure
what protocol uses ASCII formatting, has a header side of eight bytes, and is designed for transmitting documents?
HTTP/S
how does http send information across the internet?
transmission control protocol, tcp, and udp, user datagram protocol.
What happens when a website address is entered into a browser? What does Http do?
http sends a request to the site’s web server, which returns an http formatted response to the browser.
What do Http/https protocols define?
how information is formatted and transmitted
What model does http use?
request/response model
What protocol uses port 80 or 8080?
Http/ https
which version of http/https provides security?
https
what is Http supported by for device to cloud communication?
Google cloud IoT Core
etc communication protocol is a set of direct communication methods for low power devices common machines, and systems, with three primary architectural and protocol groups?
machine to machine communication protocols (M2M)
what are the three primary architectural and protocol groups in machine to machine electronic communications
representational state transfer REST
service oriented architectures SOA
message oriented protocols
what is an architectural style, in machine to machine communication protocols, for a communication amongst web accessible systems
REST, representational state transfer
what is an architecture, in machine to machine communication protocols, for data exchanges and industrial automation systems
service oriented architectures SOA
what’s a protocol for asynchronous data transfers for distributed system in machine to machine transfer protocols
message reentered protocols
what’s an internet of things data centric interaction protocol for machine to machine that uses simple publish subscribe model?
message queue telemetry transport MQTT
what supports quality of service QoS, uses TCP for sending information, and utilizes secure sockets layer SSL, and transport layer security TLS for security of the transport protocols for internet of things?
MQTT, Message queue telemetry transport
is mqtt supported by google cloud IOT core?
yes
what is a web transfer protocol for internet things constrained nodes and networks designed for machine to machine applications? it is also used for internet of things applications like building automation and smart energy management. Very similar to HTTP in that it is built on the REST model and places resources on a server accessible to clients via URL
constrained application protocol CoAP
what is an open standard for messaging amongst applications in different organizations and/or platforms, with a purpose to remove vendor lock in for app communication, and offer reliability and security in addition to interoperability?
advanced message queueing protocol AMQP
what OSI decentralized open standard for chat, messaging, video, voice calls, collaboration tools, and more. it is built on jabber, and offers a proven communication technology that is extensible flexible and diverse
extensible messaging and presence protocol XMPP
what is an API standard and middleware protocol from the object management group that exists in the applications layer between software and the operating system in the OSI model. It uses the published subscribe communications model, is data centric, provides low latency data connectivity, and helps devices and an internet of things ecosystems share data more efficiently, reliable, scalable, provides control of quality of service parameters, including bandwidth and resource limits.
Data distribution service DDS
Main ways a wireless network can be configured
ad hoc networks
wireless LAN, WLAN
mesh networks
ad hoc networks
nodes all speak directly to each other
what network configuration lets one or more access point act as a bridge between a wireless and a wired network
wireless LAN, WLAN
what network is a Hybrid of ad hoc and wireless LAN?
Mesh networks
which of the wireless nobler configurations are the simplest? every device involved within a network communicates with every other device within range and all nodes help pass along messages. not the most common type of wireless network.
ad hoc. there is no supporting network infrastructure.
what are practical applications of ad hoc networks?
individual pieces of equipment communicating with each other. phone the phone, etc.
why are at hoc networks useful during disaster situations?
if an earthquake hurricane locks out all the existing infrastructure in an area professionals can use an ad hoc network to communicate while they perform search and rescue efforts
what is the most common type of wireless network you’ll run into in the business world?
WLAN
what type of wireless network configuration consists of one or more access points which act as bridges between the wireless and wired networks? the word network operates as a normal LAN. the wired LAN contains the outbound internet link. in order to access resources outside of the network, wireless devices communicate with access points. they then forward traffic along the gateway router where everything proceeds like normal.
WLAN
what networks are like ad hoc networks since lots of the devices communicate with each other wireless?
mesh, since if you were to draw lines for all the links between all the nodes most mesh networks you’ll run into are made up of only wireless access points and will still be connected to a wired network.
what wireless network configuration lets you deploy more access points without having to run a cable to each of them? allowing you to increase the performance and range of a wireless network
Mesh
What are individual, smaller sections of an overall frequency band used by a wireless network called
channels
what does wireless networking use to address collision domains? f
channels
what is a network segment where one computer can interrupt another and communications that overlap each other can’t be understood by the receiving end, when two or more transmissions occur at the same time, and all devices in question have to stop their transmissions?
collision domain
what do devices have to do in the collision domain?
stop transmissions, wait a random amount of time, and try again when things quiet down.
what are 2.4 and 5 shorthand for?
were frequency bands actually begin. networks operate on roughly the band from 2.4 to 2.5 GHz. between these two frequencies are a number of channels with a certain width of megahertz.
what do here many channels are available for use depend on?
where you are in the world.
Why do we need a buffer around what exact frequencies of transmission might actually arrive on
radio waves are imprecise. some channels overlap but some are so far apart they won’t interfere with each other
When do you know that channels are isolated?
when channel widths do not overlap values. , cause an overlapping values. channel 1 and 6 and 11 are the only ones that never overlap.
what is most wireless networking equipment built to auto sense?
what channels are most congested
when do some access points perform analysis of which channels are congested/
when they start up. others can dynamically change their channel as needed.
What do you want to make sure of concerning your access points and those of neighboring businesses? for wireless technologies?
etc you get a little channel overlap as possible
What kind of communication has a certain amount of inherent privacy
wired connections
what devices know what data is being transmitted in a wired connection
the two nodes on either end of the link
what was invented so that we could solve the problem of anyone being able to read the radio transmissions being broadcast with the air?
WEP
WEP stands for
wired equivalent privacy
what’s an encryption technology that provides a very low level of privacy
WEP
what corresponds to help secure encryption is?
the number of bits and an encryption key corresponds to how secure it is. the more bits in the key, the longer it takes for someone to crack the encryption.
why is wired equivalent privacy so weak?
it only uses 40 bits for its encryption keys, and that can usually be cracks in just minutes.
what was wired equivalent privacy replaced by?
WPA, wifi protected access, etc uses a 128 bit key, making it a lot harder to crack.
what is the most commonly etc encryption algorithm for wireless networks today
WPA2, using 256 bit key
what’s another common way to help secure wireless networks, where you configure your access points to only allow for connections from a specific set of mac addresses belonging to devices you trust? this doesn’t do anything more to help encrypt wireless traffic, but it does provide an additional barrier preventing unauthorized devices from connecting to the network itself.
mac filtering.
