CompTIA Network+ (N10-009) Lecture Notes

Comprehensive vocabulary flashcards covering network fundamentals, the OSI model, protocols, security, cloud concepts, and troubleshooting based on CompTIA Network+ (N10-009) study materials.

Switch

A smarter hub that ensures security and efficient bandwidth utilization by making intelligent forwarding decisions based on MAC addresses.

Router

A Layer 3 device that connects different networks and makes intelligent forwarding decisions based on IP addresses.

Intrusion Detection System (IDS)

A passive security device used to detect unauthorized access or anomalies in network traffic.

Intrusion Prevention System (IPS)

An active security device that detects and take action to prevent intrusion by operating in-line with network traffic.

Client/Server Model

A network architecture that utilizes a dedicated server for centralized access to resources, offering easy administration and better scalability.

Peer-to-Peer Model

A model where resources are shared directly among peers (like laptops or desktops), which is low cost but suffers from decentralized management and poor scalability.

Personal Area Network (PAN)

The smallest network type, covering about 10 feet or less, commonly using Bluetooth or USB.

Local Area Network (LAN)

A network common in office buildings, limited to a distance of up to $100\,meters$ using CAT 5 cabling or IEEE 802.11 (WiFi).

Campus Area Network (CAN)

A building-centric network that connects multiple LANs across numerous buildings in an area like a college campus or business park.

Metropolitan Area Network (MAN)

A network that connects locations across an entire city, spanning up to $25\,miles$.

Wide Area Network (WAN)

A network that encompasses large geographic areas, connecting internal networks globally across states or countries.

Full Mesh Topology Formula

The formula used to calculate connections in a full mesh network: $\frac{n(n-1)}{2}$, where $n$ is the number of nodes.

Three-Tiered Hierarchy

A datacenter architecture consisting of the Core Layer (backbone), Distribution/Aggregation Layer (policies/routing), and Access/Edge Layer (endpoint connectivity).

North-South Traffic

Network traffic that enters (Southbound) or leaves (Northbound) a datacenter from a system outside.

East-West Traffic

Data flow specifically within a datacenter, prevalent with SDN, virtualization, and converged networks.

OSI Physical Layer (Layer 1)

The first layer of the OSI model where the transmission of raw bits occurs across physical media.

MAC Address

A unique 48-bit physical addressing system assigned to every NIC; the first 24 bits identify the manufacturer, and the remaining 24 bits identify the specific device.

TCP (Transmission Control Protocol)

A connection-oriented, reliable transport layer protocol that uses a three-way handshake (SYN, SYN-ACK, ACK) and windowing for flow control.

UDP (User Datagram Protocol)

A connectionless, 'unreliable' protocol used for time-sensitive transmissions like audio and video streaming because it has less overhead.

Transmission Control Protocol Three-Way Handshake

The connection process consisting of SYN (synchronize), SYN-ACK (synchronize-acknowledgement), and ACK (acknowledgement).

ASCI (American Standard Code for Information Interchange)

A text-based language used at the Presentation Layer (Layer 6) to ensure data is readable by the receiving system.

Protocol Data Unit (PDU)

A single unit of information transmitted in a network; specific names include Bits (Layer 1), Frames (Layer 2), Packets (Layer 3), and Segments (Layer 4).

Well-known Ports

Network ports numbered from $0$ to $1,023$ registered for specific applications like HTTP (80) and HTTPS (443).

Ephemeral Ports

Temporary, short-lived ports for dynamic use, numbered from $49,152$ to $65,535$.

ICMP (Internet Control Message Protocol)

A network layer protocol used for diagnosing communication issues, commonly utilized by the Ping and Traceroute utilities.

SMTP (Simple Mail Transfer Protocol)

The standard protocol used for sending emails, traditionally operating over port $25$.

IMAP (Internet Message Access Protocol)

An email retrieval protocol that allows managing emails directly on the server, operating over port $143$ (insecure) or $993$ (secure).

SNMP (Simple Network Management Protocol)

A protocol used for collecting information and configuring network devices, operating on ports $161$ (polling) and $162$ (traps).

Cat 5e Cable

A twisted-pair cable also known as Gigabit Ethernet, supporting $1\,Gbps$ at up to $100\,meters$.

Cat 6 Cable

A cable supporting $1\,Gbps$ at $100\,meters$ or $10\,Gbps$ at up to $55\,meters$.

Single-Mode Fiber (SMF)

Fiber optic cable designed for long distances using a small glass core ($8.3\text{ to }10\,microns$) where light travels in a single path.

Multi-Mode Fiber (MMF)

Fiber optic cable tailored for shorter distances ($2\,kilometers\text{ to }1\,mile$) with a larger core ($50\text{ to }100\,microns$) allowing light to travel in multiple paths.

UPS (Uninterruptible Power Supply)

An electrical apparatus providing emergency power and surge protection during main power failures, typically lasting $15\text{ to }30\,minutes$.

HVAC Temperature Standard

The recommended maintenance range for electronic equipment in datacenters, typically $\text{68-77°F}$ ($\text{20-25°C}$).

IEEE 802.11ax (Wi-Fi 6)

The newest wireless standard supporting 2.4 GHz, 5 GHz, and 6 GHz (Wi-Fi 6e) with speeds up to $9.6\,Gbps$.

WPA3 (Wi-Fi Protected Access 3)

A security standard that uses Simultaneous Authentication of Equals (SAE) based on the Dragonfly key exchange to prevent brute-force attacks.

CSMA/CD

Carrier Sense Multiple Access with Collision Detection; a contention-based access method used by Ethernet to manage network access and handle collisions.

VLAN (Virtual Local Area Network)

A logical subdivision of a network that segments it into separate broadcast domains regardless of physical connections.

Spanning Tree Protocol (STP)

Defined as IEEE 802.1d, it is a feature used to prevent switching loops and broadcast storms in networks with redundant links.

IPv4 Class B Range

The first octet range of $128\text{ to }191$ with a default subnet mask of $255.255.0.0$.

RFC 1918

The formal publication that defines the private IP address ranges for Class A ($10.x.x.x$), Class B ($172.16.x.x - 172.31.x.x$), and Class C ($192.168.x.x$).

APIPA (Automatic Private IP Address)

A self-assigned IP address in the range of $169.254.0.0\text{ to }169.254.255.255$, assigned by the OS when a DHCP server is unavailable.

Administrative Distance (AD)

An index of believability used by routers to select a path; lower values are more believable ($Directly connected = 0$, $Static = 1$).

MPLS (Multiprotocol Label Switching)

A 'label routing' technique used by service providers to speed up traffic flow by forwarding packets based on short path labels instead of IP headers.

SaaS (Software as a Service)

A cloud model where the provider offers a complete solution including hardware and software, such as Office 365 or Google Workspace.

SDN Control Plane

The part of Software Defined Networking responsible for routing signals and making decisions on traffic prioritization and security.

The CIA Triad

The fundamental security model comprising Confidentiality (privacy), Integrity (accuracy), and Availability (accessibility).

Zero-Day Vulnerability

A newly discovered vulnerability that is exploited by threat actors before a patch from the manufacturer is available.

On-path Attack

An attack where the adversary places their workstation between two hosts to capture, monitor, and relay communications (formerly known as man-in-the-middle).

MFA (Multifactor Authentication)

Proving identity using more than one category: Something You Know, Something You Have, Something You Are, Something You Do, or Somewhere You Are.

Troubleshooting Methodology Step 1

Identify the problem by gathering information from the user, identifying changes, and performing backups.

TDR (Time Domain Reflectometer)

A hardware tool used to locate breaks in copper cables and estimate the distance to that break.

Syslog Severity Level 0

The 'Emergency' level, indicating the system has become unstable and represents the most severe log message.

Jitter

The variation in packet delay, which is particularly detrimental to real-time applications like VoIP.

MTU (Maximum Transmission Unit)

The largest size of a frame that can be sent over a network, typically $1500\,bytes$ for standard Ethernet.