Networking Final Flashcards by Sun T

Give the order of the OSI model (top to bottom)

Application
Presentation
Session
Transport
Network
Data Link
Physical

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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

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What is the Presentation layer and give an example

Designed to identify the type of information being sent/received

Example: PDF

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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

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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

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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

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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

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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

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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)

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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

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What is a router

Passes information between networks

The router calculates how to send packets of data between networks

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What is a switch

Reads MAC addresses

Multiple devices can talk at once

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What is a hub

Signal repeated everywhere, talk and everyone hears it

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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

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What does RAID stand for

Redundant Array of Independent Disks

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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

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What RAID system does CMS use and what methods does that RAID use

RAID 5, Striping and parity

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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