Networking Final Flashcards
Give the order of the OSI model (top to bottom)
Application
Presentation
Session
Transport
Network
Data Link
Physical
What is the Application layer and give an example
Completes an identification of communication partners, provides resources, and synchronizes communications
Set of protocols and services to access resources
Example: http
What is the Presentation layer and give an example
Designed to identify the type of information being sent/received
Example: PDF
What is the Session layer and give an example
Establishes and teardown of a session
Determines if data is local or remote
Checkpoint so only the data sent after a network failure needs to be resent
Implements Class of Service
Example: FTP
What is the Transport layer and give an example
Responsible for mechanics of setup, teardown, and maintenance of a session
Encapsulate data into packet
Provides reliable or unreliable delivery of data
(Reliable requires a check after each data packet is sent, unreliable does not require a check after sending)
Example: TCP, UDP
What is the Network Layer and give an example
Connections between hosts on different networks
Defines local topology of a network
Find the logical path from source to destination
Relies on IP addresses (32 bit and 128 bit)
Routers operate on this layer (Network info updated to reflect state of network, Information stored in the routing table, used for traffic encryption)
Example: IPv4
What is the Data-Link Layer and give an example
Uses MAC addresses
Defines mechanics of physical communication
4 types of data type:
Unicast - One destination
Broadcast - Everyone on the broadcast domain
Multicast - Groups of destinations
Anycast - Data sent to receiver closest in network
Switches implemented on this layer
Ethernet and wifi for protocols
Communicate between nodes within a local layer
What is the Physical layer and give an example
Wiring
Hub acts as a physical connection
Booster will reproduce and boost the signal, increasing the maximum length
Example: Cat 5, Fibre Optic
What is Class of Service
Method of managing traffic in a network grouping similar types of traffic together and treating type as a class with its own level of service priority
Does not guarantee a level of service (bandwidth and delivery of time)
What is Quality of Service
Provide priority for certain types of data (i.e video transmission gets priority over file transfer)
Manages reliability, delay, jitter, bandwidth
What is a router
Passes information between networks
The router calculates how to send packets of data between networks
What is a switch
Reads MAC addresses
Multiple devices can talk at once
What is a hub
Signal repeated everywhere, talk and everyone hears it
What is a bridge
Bridge collects information from devices in a network to determine most efficient path for data transfer without having to send to every device in the network
Only one device can talk at a time
What does RAID stand for
Redundant Array of Independent Disks
What methods are used to distribute data in a RAID system
Striping- The process of storing consecutive segments of data across different storage devices, and allows for better throughput and performance.
Parity Bits- Write parity into a drive, allows to rebuild data if a disk fails.
Mirroring- the replication of data across two or more disks
What RAID system does CMS use and what methods does that RAID use
RAID 5, Striping and parity
Recall the Ethernet naming convention
Physical mediums:
T - Twisted Pair
F - Fibre Optic
S - Short range fibre
L - Long range fibre
K - Copper backplane
C - Balanced copper cable
B - Two wavelengths over a single optical cable
S - short-range multi-mode optical cable
L - long-range single/multi-mode optical cable
E - extended range optical cable
Z - long-range single-mode cable at high wavelength
Frequencies:
BASE - Baseband, single signal on cable
BROAD - Broadband, can have multiple signals on same channel
PASS - Passband, Wireless comms
Lanes:
1 - serial
4 or 10 - copper wire
Encoding:
X - 4B/5B Block coding for fast ethernet or 8B/10B block coding for gigabit ethernet
R - 64B/66B block coding
10Base2 - Thinnet
10Base5 - Thicknet
Draw thinnet coax cable
Look it up I can’t insert photos :(
Draw thicknet coax cable
Look it up I can’t insert photos :(
Draw fibre optic cable
Look it up I can’t insert photos :(
Bandwidth vs. throughput
Bandwidth - Amount of packets/data that can be transmitted over a network or communication channel in a given period of time
Throughput - actual amount of data that is transmitted over a network or communication channel in a given period of time
What is latency
Network latency is the delay in network communication. It shows the time that data takes to transfer across the network. Networks with a longer delay or lag have high latency, while those with fast response times have low latency.
What is jitter
jitter is a variance in latency, or the time delay between when a signal is transmitted and when it is received
Lossy vs. Lossless data compression
Lossless - Group patterns together and repeat them to shrink packet size (chair in a white background example from class)
Lossy - Lose quality to shrink file size
What is packet shaping
Delay certain types of packets so that other packets can get higher speed
What is caching
storing copies of files in a cache, or temporary storage location, so that they can be accessed more quickly [i.e you want to re-visit a website you just closed]
What is a firewall
Used to filter traffic and lower the risk of malicious packets traveling over the internet
What is a VPN (Virtual Private Network)
an encrypted connection over the Internet from a device to a network. The encrypted connection helps ensure that sensitive data is safely transmitted. It prevents unauthorized people from eavesdropping on the traffic and allows the user to conduct work remotely.
What is tunneling
Tunnels are a method for transporting data across a network using protocols that are not supported by that network. Tunneling works by encapsulating packets: wrapping packets inside of other packets
Use with VPNs.
What is a hash function
A function used to map data to a fixed size
Use a hash table to provides fast lookup of data
What is symmetric encryption
Both sender and receiver of info have same key
What is asymmetric encryption
Sender and receiver have different keys (public vs. private keys)
Public key given to public to encrypt information to send to you
Private key can decrypt information
Private key linked mathematically to private
What are the types of symmetric encryption
Data Encryption Standard - breaks up data into small chunks to encrypt using a key, NOT computationally secure
Advanced Encryption Standard - computationally secure, 128 bits
What are digital signatures
Verify senders’ identity
Private key encryption, anyone with public key can verify who signed the message
What is the Diffie-Hellman algorithm
Exchange crypto keys over a public network
At end of communication both parties have the same key
Study slides for actual algorithm can’t add pics and too lazy to type out
What is the goal of cybersecurity
Confidentiality, integrity, availability, non-repudiation
What is a cyber attack
An attack is any attempt to expose, alter, disable, destroy, steal or gain access to an asset
What is the cyber killchain
Steps are as follows:
Reconnaissance
Weaponization
Delivery
Exploitation
Installation
Command and Control
Actions on objectives
To be successful in a cyber attack, must follow the kill chain stpes
Syntactic vs. Semantic attacks
Syntactic - straightforward attack, uses malicious software (viruses, worms, trojan)
Semantic - Trick user into carrying out an action (user installs anti-virus that’s actually remote access application)
Virus vs. Worm vs. Trojan
Virus - replicates itself by modifying other computer programs and inserting its own code
Worms - Spread by exploiting vulnerabilities in operating systems , spread across a network
Trojans - Malware that misleads users of its true intent
What is Tempest
Telecommunications Electronics Materials Protected from Emanating Spurious Transmissions
Certification to equipment for EMI protection
Level I - Stringent
Level II
Level III - Relaxed
Thin client vs. Thick client
Thin client - Computer system that runs on a server-based computing environment, connects to a remote server where applications and data is stored
Thick client - System that can be connected to the server without the network, have own OS and software applications
