Introduction To Networking Concepts Flashcards
Networking models
Transmission control protocol and internet protocol (TCP/IP)
Open systems interconnection (OSI)
The four layers of the TCP/IP model
Network interface
Network
Transport
Application
The seven layers of the OSI model
- Physical
- Data link
- Network
- Transport
- Session
- Presentation
- Application
What is the role of the network interface layer of the TCP/IP model?
Contains the physical cabling or the wireless spectrum
What is the role of the network layer of the TCP/IP model?
Where the internet protocol (IP) and the internet control message protocol (ICMP) run?
What is the role of the transport layer of the TCP/IP model?
Ensures data is delivered to the correct application. Data transfer is done through TCP or user datagram protocol (UDP). TCP resends messages if not delivered, UDP does not. This makes UDP better for audio streaming.
What is the role of the application layer of the TCP/IP model?
Handles communication protocols between nodes
What is the role of the physical layer of the OSI model?
Contains cabling and connectors. Establishes how a signal crosses a wire and/or the airwaves.
What is the role of the data link layer of the OSI model?
Includes your network card which has the media access control (MAC) address. Functions like a bridge.
What is the role of the network layer of the OSI model?
Where the internet protocol (IP) and the internet control message protocol (ICMP) run
What is the role of the transport layer of the OSI model?
Ensures data is delivered to the correct application. Data transfer is done through TCP or user datagram protocol (UDP). TCP resends messages if not delivered while UDP does not.
What is the role of the session layer of the OSI model?
Establishes the session and ensures end to end functionality
What is the role of the presentation layer of the OSI model?
Data encryption
What is the role of the application layer of the OSI model?
Communication protocols
Switch
A second layer (data link) device that keeps traffic between the source and destination parts from interfering with other devices in the network.
Router
A third layer (network) device that can connect your home network to the internet, or for businesses, your web server to your database server.
Firewalls
Can operate between the second and 7th layers. Firewalls are like filters between layers in order to prevent malware from getting through.
Modems
Allows computers to transport digital information over analog lines.
First and second layer device
Bridge
A layer two device similar to a router but instead forwards messages without analyzing.
Repeater
A layer one device used to strengthen weakened signals
Hub
A layer one device that connects the router to the network, takes data packets from routers and sends them to all connected networks
What are the four main types of cables?
Unshielded twisted pair (UTP)
Shielded twisted pair (STP)
Fiber optic
Coaxial
Why are fiber optic cables preferred in the modern age?
Fiber optic cables use light instead of electrical signals which makes them more durable and secure. Data is transferred digitally, which reduces time needed to translate.
Coaxial cable
Copper cables with a metal shield intended to block signal interference. Mainly used today for television
Crossover
Used to connect two devices at the same time
Patch
Used to connect a device to a wall outlet
UTP connector types
RJ11: supports two pairs of wires typically used in telephones
RJ45: an end connector that is typically used with ethernet cables. Four pairs instead of two
Fiber optic connector types
Straight tip (ST): used with multi-mode cables till mid 2000s
Lucent (LC): most common in corporate data centers today
Sudo
Allows for super user access so a user can run commands as an administrator
ifconfig
Shows how interfaces are set up in a machine
route
Defines the path a data packet takes between networks
ping
Verifies connectivity and latency
nslookup/dig
Helps resolve a name associated with an IP address
traceroute/tracert
Finds the route a packet takes
whois
Finds out who owns a domain and more information about the domain such as registry information and organization information
tracepath
Similar to tracert but can be used by any user, not just admins
ipconfig
Provides the user with information about each network adapter
ARP
Displays the IP to physical (MAC) address mappings
netstat
Displays information about active ports and their state
scp
Securely copies files between servers
ftp
Copies files from one host to another unencrypted
tftp
Transfers files from a client to server or vice versa
finger
Displays information about users (Linux)
nmap
Scans Network for hosts and open ports
tcpdump
Displays TCP/IP packets transmitted over network
telnet/ssh
Allows a user to manage accounts and devices remotely. SSH is encrypted while telnet is not
Personal area network (PAN)
Connects personal devices within 20 to 30 m
Local area network (LAN)
Uses a router or switch to manage traffic.Works for single buildings
Campus area network (CAN)
Works for multiple buildings. Connects LANs to create a CAN
Metropolitan area Network (MAN)
City-wide network
Storage area network (SAN)
A LAN used for storage to reduce interference from normal LAN traffic
Wide area network (WAN)
In principal has no limits on coverage
Client – server
Involves a server with the data and information and a machine that needs access to that data
Peer-to-peer
Each machine on the network can act as both server and client
Bus network topology
Commo in early networking. The ends of the cable are terminators which absorb stray electrical signals without these signal reflection occurs.
Star Network Topology
Most common type for LANs
Centralization
Nearly all computing and network power is centralized in a large data center, machines accessing that data are referred to as “dumb terminals”
Decentralization
Can eliminate the need for a central data center. Microcomputers made this possible.Challenges include proper backup files, local security and incompatibility between files for users. Benefits include the ability to operate without a network connection and computers that do not rely on each other.
Virtualization
The technique of converting a hardware-based resource in two software. Virtualization allows for deploying new devices quickly without physical installation, separating applications from single points of failure (SPoFs) and on demand resource allocation.
Hypervisor
A special type of software that creates virtual hardware for devices
Type 1 hypervisors
Operating systems that have complete access to the physical hardware administrators use a web browser to access.
Type 2 hypervisors
Applications that must compete for resources with other applications
Infrastructure as a service (IaaS)
The cloud service provider manages the underlying infrastructure, but the client controls the operating system and virtual machines
Platform as a service (PaaS)
Service provider offers the platform on which to build the code on. The client controls the applications.
Software as a service (SaaS)
The cloud provider runs the entire physical infrastructure including virtual machines, operating systems, middleware, and applications
Private cloud
Equipment is hosted on or off premises in which the company/cliet has complete control/ownership of equipment.
Public cloud
Cloud provider is responsible for the hardware and infrastructure instead of the client
Community cloud
Data centers jointly owned and operated by the tenants
Hybrid cloud
Combination of private and public clouds that require a dedicated connection between them
Multi-cloud
The concept of leveraging the services of multiple public cloud providers
Asset
A person, device, location, or information that security operations aims to protect from attacks.
Attack
An action taken by a threat that exploits a vulnerability that attempts to either block authorized access to an asset or to gain unauthorized access to an asset.
Risk
The potential of a threat to exploit a vulnerability via an attack
SecOps
IT security operations; a discipline within IT responsible for protecting assets by reducing risk
Threat
Something or someone that can exploit a vulnerability to attack an asset
Vulnerability
A weakness in software, hardware facilities or humans that can be exploited by a threat