CompTIA Network+ N10-009 Vocabulary Review

Comprehensive practice flashcards defining core vocabulary, concepts, protocols, and hardware from the CompTIA Network+ N10-009 Last Minute Cram review notes.

Physical Layer (Layer 1)

The layer of the OSI model responsible for transmitting raw bits over network media, encompassing physical hardware such as cables, switches, electrical signals, and light pulses.

Data Link Layer (Layer 2)

The layer of the OSI model responsible for node-to-node data transfer, framing, addressing, and physical error detection and correction, subdivided into the MAC and LLC sublayers.

Media Access Control (MAC) Sublayer

The lower sublayer of the Data Link Layer that manages protocol access to the physical transmission medium and controls hardware addressing via MAC addresses.

Logical Link Control (LLC) Sublayer

The upper sublayer of the Data Link Layer that provides multiplexing to allow multiple network protocols to coexist over a common medium while supplying flow and error control.

Network Layer (Layer 3)

The layer of the OSI model responsible for logical addressing, packet forwarding, congestion control, and determining the best path for data transmission using routing protocols.

Transport Layer (Layer 4)

The layer of the OSI model responsible for transparent and complete end-to-end data transfer between systems, utilizing error correction, flow control, and data segmentation/reassembly.

Session Layer (Layer 5)

The layer of the OSI model that sets up, maintains, coordinates, and terminates communication sessions and dialogs (half-duplex or full-duplex) between presentation layer entities.

Presentation Layer (Layer 6)

The layer of the OSI model that handles data translation, syntax formatting, encryption, and compression between application-level representations and network formats.

Application Layer (Layer 7)

The layer of the OSI model that interfaces directly with end-user software processes and defines protocols for network services such as email, file transfers, and web browsing.

Layer 3 Switch

A multilayer networking device capable of performing both standard Layer 2 switching based on MAC addresses and Layer 3 routing based on IP addresses to interconnect subnets and VLANs.

Intrusion Prevention System (IPS)

A network security device that inspects traffic and actively blocks or prevents detected malicious activities, policy violations, and anomaly signatures.

Intrusion Detection System (IDS)

A passive security device that monitors network and system activity for suspicious actions and alerts administrators without actively blocking the traffic.

Content Delivery Network (CDN)

A globally distributed network of proxy servers and data centers that caches static and streaming web content closer to users to reduce latency and speed up delivery.

Network Functions Virtualization (NFV)

The architecture of decoupling network functions (such as firewalls, load balancers, and routing) from dedicated physical hardware to run as software instances on VMs or containers.

Virtual Private Cloud (VPC)

An isolated, private network space provisioned within a public cloud where organizations manage custom IP ranges, subnets, route tables, and gateways.

Infrastructure as a Service (IaaS)

A cloud service model providing virtualized computing resources, servers, data storage, and networking over the internet on a scalable, pay-as-you-go basis.

Platform as a Service (PaaS)

A cloud service model providing developers with hosted environments, platforms, and management tools to build, test, and deploy applications without handling underlying infrastructure.

Software as a Service (SaaS)

A cloud computing model delivering centrally hosted applications directly to clients over the internet, typically accessed via a web browser on a subscription model.

Multitenancy

A software architecture where a single running instance of an application serves multiple distinct customer organizations (tenants), while maintaining logical isolation of each tenant's data.

Elasticity

The ability of a cloud infrastructure to dynamically and automatically provision or de-provision computing resources in real time according to current workload demands.

Simple Network Management Protocol (SNMP)

An application layer protocol operating over UDP ports 161 (polling/commands) and 162 (traps) used to monitor, configure, and manage network devices.

Server Message Block (SMB)

A network protocol operating over TCP port 445 used primarily by Windows environments for network file sharing, printer sharing, and inter-process communication.

Session Initiation Protocol (SIP)

A signaling protocol that operates on port 5060 (unencrypted) and 5061 (TLS) to initiate, maintain, modify, and terminate multimedia communication sessions such as VoIP calls.

Generic Routing Encapsulation (GRE)

A tunneling protocol developed by Cisco that encapsulates a broad variety of network layer protocol packets inside virtual point-to-point IP tunnels.

Encapsulating Security Payload (ESP)

An IPSec protocol component that provides data confidentiality through encryption, data-origin authentication, connectionless integrity, and anti-replay protection for IP packets.

Anycast

A network addressing and routing scheme where incoming packets are routed to the nearest or best available destination node among a group sharing the exact same IP address.

802.11ax (WiFi 6)

A high-efficiency WLAN standard operating across 2.4 GHz and 5 GHz frequency bands, delivering speeds up to 9.6 Gbps and using OFDMA and BSS Coloring to mitigate congestion.

Single-Mode Fiber (SMF)

A fiber-optic cable with a narrow core designed to propagate only a single mode of light, minimizing attenuation and dispersion for long-distance transmissions spanning several kilometers.

Multimode Fiber (MMF)

A fiber-optic cable with a larger core diameter allowing multiple modes of light to travel simultaneously, commonly used for high-speed, shorter-distance deployments (up to 500 meters or 2 km).

Twinaxial Cable (Twinax)

A shielded cable with two inner conductors used in high-speed, short-distance differential signaling environments such as 10 Gigabit Ethernet links between rack switches and servers.

Small Form-Factor Pluggable (SFP)

A compact, hot-swappable transceiver module used to interface networking hardware with fiber-optic or copper cabling at speeds up to 1 Gbps.

Quad Small Form-Factor Pluggable (QSFP)

A high-density transceiver module providing four times the bandwidth of standard SFP+ modules, combining four 10 Gbps channels to achieve data rates up to 40 Gbps.

Multi-Fiber Push On (MPO)

A high-density optical connector designed to terminate and connect multiple individual optical fibers (commonly 12 or 24) within a single rectangular connector.

Spine and Leaf

A two-tier data center switching architecture where every leaf switch connects to every spine switch, ensuring predictable latency by keeping all access nodes separated by no more than two hops.

Collapsed Core Architecture

A network design that combines the core and distribution layers into a single switching layer, streamlining management and reducing hardware costs in small-to-medium networks.

North-South Traffic

Network data packets moving inbound and outbound between a data center environment and external endpoints, such as clients on the public internet.

East-West Traffic

Data communications flowing strictly within an internal data center facility, including server-to-server, VM-to-VM, and storage-network transfers.

Automatic Private IP Addressing (APIPA)

A feature in Windows operating systems that automatically assigns a link-local IPv4 address in the range 169.254.0.1 through 169.254.255.254 when a DHCP server cannot be reached.

RFC 1918

The internet standard defining reserved private IP address ranges not routable across the public internet: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16.

Variable-Length Subnet Mask (VLSM)

A subnetting methodology allowing subnets of differing sizes within the same network address space, optimizing address allocation and reducing unused IP wastage.

Software-Defined Wide Area Network (SD-WAN)

An architecture applying software-defined networking concepts to WAN links, intelligently and dynamically routing enterprise traffic over varied connection types using central policy control.

Virtual Extensible Local Area Network (VXLAN)

An overlay encapsulation technology that encapsulates Layer 2 Ethernet frames inside Layer 3 UDP packets to expand network segmentation beyond the traditional 4096 VLAN limit.

Zero Trust

A cybersecurity paradigm centered on 'never trust, always verify,' enforcing strict per-session identity verification and least-privilege access for all users, devices, and requests.

Infrastructure as Code (IaC)

The DevOps and cloud practice of provisioning, configuring, and managing computing environments through version-controlled, machine-readable definition files rather than manual procedures.

Configuration Drift

The gradual divergence of a system's or network's actual running state from its intended, documented baseline due to unrecorded manual alterations and updates.

Dual Stack

An IPv6 transition method where network interfaces and nodes run both IPv4 and IPv6 protocols simultaneously, enabling concurrent communication over either protocol.

NAT64

An address translation technology that translates IPv6 packets into IPv4 packets (and vice versa) to facilitate direct communication between IPv6-only and IPv4-only hosts.

Border Gateway Protocol (BGP)

The standardized exterior gateway routing protocol used across the global internet to route traffic between distinct autonomous systems (ASes).

Administrative Distance

A numerical ranking of route trustworthiness used by routers to select the best path when identical destinations are learned from multiple different routing protocols, where lower values are preferred.

Port Address Translation (PAT)

A form of NAT (also called NAT overload) that maps numerous private IP addresses to a single public IP address by assigning unique source port numbers to each connection.

First Hop Redundancy Protocol (FHRP)

A family of resilience protocols (such as VRRP) that allows redundant routers to share a virtual IP address, providing automatic failover if the primary default gateway goes down.

Switch Virtual Interface (SVI)

A logical Layer 3 interface configured on a multilayer switch that assigns an IP address to an entire VLAN to enable inter-VLAN routing.

Spanning Tree Protocol (STP)

A Layer 2 protocol that prevents switching loops and broadcast storms by monitoring network paths and placing redundant physical links into a blocking state.

Maximum Transmission Unit (MTU)

The maximum data payload size (measured in bytes) that can be transmitted in a single packet or frame without undergoing fragmentation, typically 1500 bytes for standard Ethernet.

Jumbo Frames

Ethernet frames configured to carry payloads larger than the standard 1500-byte limit (commonly up to 9000 bytes) to minimize processing overhead in high-throughput environments.

Band Steering

A wireless controller technology that detects dual-band client devices and automatically encourages or steers them from the congested 2.4 GHz band to 5 GHz or 6 GHz channels.

Basic Service Set Identifier (BSSID)

The unique Layer 2 MAC address of an individual wireless access point's radio interface used to identify a specific physical AP within a wireless network.

Extended Service Set Identifier (ESSID)

The broadcasted wireless network name shared across multiple access points in an enterprise WLAN to allow seamless client roaming across physical access zones.

Intermediate Distribution Frame (IDF)

A secondary telecommunications room or rack located on floors or distinct sections of a building that consolidates local cabling and links back to the central MDF.

Main Distribution Frame (MDF)

The primary central equipment room and wiring hub in a building where incoming external service provider circuits interconnect with the internal network backbone.

Recovery Point Objective (RPO)

The maximum acceptable age of data loss measured back in time from an unplanned outage that an organization can sustain without intolerable business damage.

Recovery Time Objective (RTO)

The targeted duration of elapsed time within which a business system or service must be fully restored and operational following a disaster.

Mean Time Between Failures (MTBF)

The statistically calculated average operational lifespan expected of a hardware component or system between breakdowns.

Mean Time to Repair (MTTR)

The average amount of time required to diagnose, repair, and restore a failed system or network component back to functioning status.

Stateless Address Autoconfiguration (SLAAC)

An automated IPv6 configuration process whereby a host generates its own unique IP address using prefix advertisements from a local router and its own MAC address.

DNSSEC

A suite of DNS security extensions providing cryptographic origin authentication and integrity checking for DNS queries and responses to prevent cache poisoning.

Canonical Name (CNAME) Record

A DNS record type that associates an alias or alternate domain name with an authoritative canonical domain name.

Pointer (PTR) Record

A DNS record that maps an IP address back to its associated hostname, serving as the foundational record for reverse DNS lookups.

Precision Time Protocol (PTP)

A network time protocol defined in IEEE 1588 that provides high-precision time synchronization down to sub-microsecond or nanosecond levels for industrial and measurement systems.

Screened Subnet (DMZ)

A physical or logical subnetwork acting as a neutral buffer between an organization's untrusted external network and trusted internal private network, hosting public-facing services.

MAC Flooding

An attack that inundates a network switch's CAM table with thousands of fake MAC addresses, forcing it into a fail-open state where incoming frames are broadcast out of all ports.

ARP Poisoning

An attack in which an adversary sends falsified ARP reply messages across a local LAN to link their own MAC address with the IP address of a legitimate default gateway or server.

Port Security

A Layer 2 defense feature on network switches that limits and restricts access to specific switch ports based on permitted MAC addresses, blocking unauthorized devices.

Link Layer Discovery Protocol (LLDP)

An open, vendor-neutral Layer 2 discovery protocol that network devices use to advertise their identities, configurations, and capabilities to adjacent neighbors on a local network segment.

Cisco Discovery Protocol (CDP)

A proprietary Layer 2 protocol used by directly connected Cisco devices to discover and share hardware models, IP addresses, software versions, and port capabilities.