2do Parcial Flashcards
what is hot swap?
swaping any part of a server without turning it off.
what are mission critical servers?
servers that can never be off (hospitals, banks)
what’s the difference between gabinet and rack?
A rack is a set of units of hardware where data is stored in servers, a gabinet is like a rack, only with a door.
what is a data center?
its a facility that can be private (a room within an organization) that houses an organizations IT operations where the racks are managed. The data is processed in data centers. They need to have thermal regulators,
Data centers are usually supported and managed by one of four categories
- enterprises
- multi-tenant data center and colocation facilities
- hyperscale and cloud
- carrier and service provider
Within a data center, the following technical spaces are managed by the provider:
- PHYSICAL SECURITY SYSTEMS
- NETWORK AND IT SYSTEMS
- POWER RESOURCES
- ENVIRONMENTAL CONTROL
- PERFORMANCE AND
- OPERATIONAL MANAGEMENT
The technical spaces within a data center tackle the following challenges:
- risk management: 6 layer approach the first one is the perimeter , the clear zone, facade and reception, service corridor, the data hall, data cabinet
- network migration
- power optimization
- thermal efficiency
- DCIM enablement
What is MDA in a data center?
MDA- Main distribution area: houses core network equipment like routers, switches and connections to external networks.
What is an HDA in a data center?
HDA-horizontal distribution area: intermediate between the MDA and EDA
What is EDA in a data center?
EDA- equipment distribution area: zone closest to the actual hardware (servers, storage devices) where the connections from the HDa reach end-user equipment.
What is multitenency?
When customers can share the resources of each server in a data center.
What is a Tier 1 data center?
Tier 1: Used by small businesses with
- minimal IT requirements
- no need for high availability
- some downtime is acceptable.
- 99.671% uptime
- 28.8 hours of downtime per year
- no redundancy.
What is a Tier 2 data center?
Tier 2: Small to medium businesses
- more reliability
- not full redundancy
- some tolerance for downtime.
- 99.749% uptime
- 22 hours of downtime
- partial redundancy in power and cooling.
What is a Tier 3 data center?
Tier 3: Large businesses
- consistent uptime
- can afford minimal downtime
- ie. ecommerce
- 99.982% uptime
- 1.6 hours of downtime
- N+1 fault-tolerant
- 72 hours of power outage protection.
What is a Tier 4 data center?
Tier 4: mission-critical environments/ enterprise corporations
- Highest level of redundancy and protection.
- 99.995% uptime
- 2.4 minutes of downtime
- 2N+1 fully redundant systems.
What is a thin client model?
The server takes charge of: data management, application processing
The client takes charge of: minimal local tasks
What is a fat client model?
The server takes charge of: data management
The client takes charge of: tasks that demand more local resources, gaming or graphic design.
What is scaling up/down or vertically?
It means adding (or removing) resources to a single node, typically the addition of CPUs, memory or storage to a single computer.
What is scaling out/in or horizontally?
It means adding (or removing) more nodes to a system, such as a new computer to a distributed software application.
How does freedom of movement differ between a wireless network and a wired network?
Wireless networks: Users can access anywhere with an internet connection.
Wired connection: Limited to the distance between the wire and port.
How do costs differ between a wireless network and a wired network?
Wireless network: relatively accessible
Wired network: expensive instalation
How do cables differ between a wireless network and a wired network?
Wireless network: uncomplicated wiring
Wired network: complicated wiring
How does business differ between a wireless network and a wired network?
Wireless network: businesses with public access is needed to increase the revenue.
Wired network: Not recommended for public use, only for office work.
How does velocity differ between a wireless network and a wired network?
Wireless network: lower
Wired network: higher
How does security differ between a wireless network and a wired network?
Wireless network: less secure; bandwidth and information is vulnerable outside the instalations.
Wired network: more secure than wireless as it is intramural
How does set up differ between a wireless network and a wired network?
Wireless network: easy and quick to configure
Wired network: hard and requires more time to configure it.
What is an OSI model?
Open Systems Interconnection Model standardizes the functions of a network into seven layers.
What are the layers in an OSI model?
- Application
- Presentation
- Session
- Transport
- Network
- Data Link
- Physical
What happens on the application layer of the OSI model?
A file is created and sent to a translator for the data to be sent through software.
What happens on the presentation layer of the OSI model?
It translates data formats and encryption.
What happens on the session layer of the OSI model?
It manages connections between applications, the emissor and recipient.
What happens on the transport layer of the OSI model?
It ensures reliable data transfer and chooses between TCP or UDP depending on what’s needed.
What happens on the network layer of the OSI model?
IP adressing and routing is handled. It’s like adding an address to a package.
What happens on the data link layer of the OSI model?
The data is translated to the right format for its transmition.
What happens on the physical layer of the OSI model?
The data is sent through data transmission (light, radio signals, electricity)
What is the TCP/IP model?
Transmission Control Protocol/ Internet Protocol
It’s a more practical, 4 layer protocol that standardizes internet communication:
What are the layers on a TCP/IP model?
- Link
- Internet
- Transport
- Application
What happens on the link layer of the TCP/IP model?
It handles data transfer accross physical networks.
Similar to OSI’s physical and data link layers.
What happens on the internet layer of the TCP/IP model?
It’s responsible for IP addressing and packet forwarding (IP protocol).
Similar to OSI’s network layer.
What happens on the transport layer of the TCP/IP model?
It uses protocols like TCP and UDP
Similar to OSI’s transport layer.
What happens on the application layer of the TCP/IP model?
It uses protocols like HTTP, FTP, SMTP, etc
It combines OSI’s session, presentation and application layers.
What does TCP stand for?
Transmission Control Protocol
It sends data packets ensuring that they meet the recipient.
It’s reliable, ordered and error-checked and connection-oriented.
What does UDP stand for?
User Datagram Protocol
A protocol that sends data packets without guaranteeing reliable delivery.
It’s faster, connectionless data transfer and often used for streaming and gaming.
What does HTTP stand for?
Hypertext Transfer Protocol
It’s a protocol used for transmitting data over the web.
It operates on a request-response model and is stateless
During what layer are packets sent on an OSI and TCP/IP model?
On the physical and link layer accordingly.
What is Wi-Fi?
Wireless Fidelity
Is a technology that uses radio waves to transmit data between a wireless router and devices.
What is NFC?
Near Field Communication
Is a wireless communication technology that allows two devices to exchange data over a short range.
-Minimum 4 cm
-for payment methods, publicity, check-in systems, data exchange, public transport and access control
What is RFID?
Radio Frequency Identification
A technology that uses electromagnetic fields to identify and track tags attached to objects.
-Minimum 1 m
-Divided in
-passive RFID:the user reads the information on the tag. Ideal for devices without batteries.
- active RFID: the tags transmit data over longer distances.
- passive assisted RFID: active when the reader is nearby. For clothes and TAG
What is 802.11ah Wi-Fi?
Also known as WiFI HaLow.
Designed for low-power, long-range communications.
- 900 MHz band
- doesn’t increase speed
- maximizes distance
- low frequency to penetrate through more objects
- less energy consumption
What is LPWAN?
Low Power Wide Area Network
a category of wireless communication technologies designed for:
- low power consumption
- long-range communication
- wireless
- ideal for a large number of devices
- IoT devices with minimal energy usage
What is NB-IoT and LTE-M?
NB-IoT (narrowband IoT) and LTE-M (Long Term Evolution for Machines) are low-power wide-area cellular network technologies designed specifically for IOT applications.
- mainly indoors and long distance
- low energy consumption
- using existing cellular networks like 2G (GSM), 3G, 4G LTE and 5G
- for connecting a large number of devices
How does 5G compare to 2G characteristics?
2G
- 1991
- basic mobile communication
- low data transfer rates
- voice and SMS mostly
5G
- 2020
- extremely high data speeds
- low latency
- supports massive IoT
- smart cities
- advanced real-time applications
- 1hr of HD movie in 6 seconds
What is BLE?
Bluetooth Low Energy
a wireless communication standard designed for low power consumption while maintaining a good communication range.
- 2.4GHz frequency band
- short range, up to 100 m
- star topology (1 device controls all the others)
- ideal for small volumes of data
- the devices turn off to save energy
- wearables, fitness trackers and smart home devices
How does IPv4 compare to IPv6?
IPv4
- deployed in 1981
- 32-bit address
- 4.3 billion unique addresses (2^32)
- written in dotted decimals
- ie. 192.168.0.1
IPv6
- deployed in 1999
- 128-bit address
- 340 undecillion unique addresses (2^128)
- written in hexadecimal and colons
- ie. 2001:0db8:85a3::8a2e:0370:7334
IP is related to the OSI model on layer ___, the ___ layer, as it uses this protocol to connect between hosts.
5
Network
What is WPAN?
Wireless Personal Area Network
a type of wireless network
- short range: 10-100 m
- for home automation systems, connecting personal devices and health monitors
- suitable for battery operated devices
- ie. Bluetooth, Zigbee, Infrared (IR)
What is WLAN?
Wireless Local Area Network
a type of wireless network
- short/medium range: 100-1000 m
- for internet access at home or public hotspots, file sharing, streaming and gaming
- high-speed data transfer
- ie. WiFi IEEE 802.11
What is WMAN?
Wireless Metropolitan Area Network
a type of wireless network
- medium range: 5-10 km
- for internet access to multiple buildings across the city, campus network
-High-speed data transfer, suitable for broadband services.
ie. WiMAX, LTE
What is WWAN?
Wireless Wide Area Network
a type of wireless network
- long range: up to 100 km
- for regions, countries or continents
- enables mobile connectivity and internet access over vast distances, high reliability and availability
- extensive infrastructure (cell towers, satellites, ground stations)
- IoT connectivity, mobile devices on the go, voice and data services
- ie. 4G, 5G, satellite networks
Mention the stages of data processing:
Data, Information, Knowledge, Wisdom
Data needs 3 things to turn into wisdom:
Understanding, context and experience
Data needs 3 things to turn into wisdom, one of those is context, how does it evolve?
- Gathering of Parts (data)
- Connection of Parts (information)
- Formation of a Whole (knowledge)
- Joining of wholes (wisdom)
Data needs 3 things to turn into wisdom, one of those is understanding, how does it grow?
- Researching
- Absorbing
- Doing
- interacting
- Reflecting
What is unstructured data?
Data that’s harder to analyze because it lacks a predefined format.
ie. text documents, videos, images, GPS tracking
What is structured data?
Data that is highly organized and easy to analyze.
ie. databases, spreadsheets, data warehouses, CRM
What is semi-structured data?
A type of data that doesn’t perfectly fit into databases (structured data) but still has some level of organization through tags or markers.
ie. XML, CSV files
What is hot data and why is it stored in SSDs?
High performance data that needs to be quickly retrieved (time-sensitive).
SSDs are used to store this type of data because of their high read/write speeds and low latency.
What is nearline or warm data and why is it stored in HDDs?
Capacity optimized data that’s less frequently accessed but still requires reasonable availability.
It uses HDDs because they provide larger storage capacity at lower cost.
What is cold data and why is it stored in Cloud storage or object storage?
Cheap and deep data that is rarely accessed and not time-sensitive.
These storage solutions offer cost-efficient options for archiving or long-term data retention.
What is a DAS?
Direct-Attached Storage
A type of data storage solution.
Storage directly attached to a computer or server.
- Simple but isolated
- Not easily shared between devices
What is a NAS?
Network-Attached Storage
A type of data storage solution.
Storage device connected to a network
- allows multiple users or devices to access and share data over the network
- for 100-200 employes
- ie. you can save family pictures without using you computer’s storage
What is a SAN or FC?
Storage Area Network or Fibre Channel
A type of data storage solution.
- high-speed
- connected through fibers
- they have a NIC (network interface card)
- accessible by multiple servers at the same time
- can assign and reassign data slots as you please
- can take HotSwap to reduce DownTime
- commonly used in enterprise environments for data-heavy applications
- ie.banks and insurance companies
Does the Cloud store or process information?
The cloud does both storing and processing information as it is not just the infrastructure.
What is RAID?
Redundant Array of Independent Disks
It is one of the best ways to prevent data lost against failure. RAID basically copies the information in different disks.
What are some advantages and disadvantages of RAID 0?
striping
Advantages
-good reading and writing performance
- uses all the storage capacity
- easy to implement
Disadvantages
- if one block fails, all data is lost
- not recommended for mission critical
What are some advantages and disadvantages of RAID 1?
mirroring
Advantages
- great reading and writing performance
- if one block fails, you must copy the information from the other disk
- easy to implement
Disadvantages
- can only use half of the capacity
- if one disk fails, sometimes it wont take hot swap
What are some advantages and disadvantages of RAID 5?
striping with parity across drives
Advantages
- fast reading
- if one disk fails, you can recover the information
- can reconstruct the lost disk quickly
Disadvantages
- slow writing because of the parity
- if one disk fails, it can slow down
- complex technology
- restoration can take a while
What are some advantages and disadvantages of RAID 10?
mirroring+striping
Advantages
- if one disk fails, reconstruction is very quick as it will copy the information from the drive that mirrors it
- 30m/1TB
Disadvantages
- half of the capacity is used on mirroring
- expensive to have redundancy
