Comprehensive Networking Practice Flashcards

Comprehensive practice vocabulary flashcards covering fundamental networking concepts including network topologies, hardware media, protocols, OSI and TCP/IP models, IP addressing (IPv4/IPv6), subnetting, DHCP, ARP, routing, transport layer mechanics, and network testing utilities.

Internet

An open global collection of interconnected networks (network of networks) that is not owned by any one individual, group of individuals, or government.

Small Office/Home Office (SOHO) Network

A small network installed in a home or remote office that enables users to share resources (such as printers, documents, and pictures) and connect to the internet.

RFID Tag

A Radio Frequency Identification device placed on objects to track and monitor them.

Bit

The smallest unit of data in computing, which can have one of two possible binary values: $0$ or $1$.

Byte

A group of 8 bits representing a single character or data unit in digital communications.

Throughput

The measure of the actual transfer of bits across network media over a given period of time, which is constrained by the slowest link along the communication path.

End Device

A network component—such as a desktop computer, laptop, network printer, or tablet—that serves as the interface between humans and the communication network, originating or receiving data.

Intermediary Device

A network device, such as a router, switch, or firewall, that directs data across the network along alternate paths between source and destination end devices.

Peer-to-Peer (P2P) Network

A decentralized network model where individual devices can act simultaneously as both clients and servers, offering ease of setup and low cost but lacking centralized administration and scalability.

Internet Service Provider (ISP)

An organization responsible for providing the communication link between a private customer network and the public internet.

Digital Subscriber Line (DSL)

An always-on, high-bandwidth connection that transmits digital signals over regular telephone lines by splitting the line into voice, download, and upload channels.

ISP Services

A suite of centralized services offered by an Internet Service Provider, which include web hosting, FTP hosting, application/media hosting, VoIP, POP internet access, equipment co-location, and technical support.

Satellite Internet

A wireless internet connectivity method requiring a clear line of sight to an orbiting satellite, commonly deployed in remote rural locations lacking wired cable/DSL or cellular coverage.

Wi-Fi

A wireless local area network technology based on IEEE 802.11 standards that transmits data across radio frequencies (primarily $2.4\text{ GHz}$ and $5\text{ GHz}$).

Bluetooth

A low-power, short-range wireless technology operating at $2.4\text{ GHz}$ designed to connect peripheral devices, such as hands-free headsets or computer accessories, to a host device.

Near Field Communication (NFC)

A wireless communication technology that establishes radio communication between two devices when placed in very close proximity or touched together, frequently utilized in smartphone payment terminals.

Global Positioning System (GPS)

A satellite-based navigation system enabling a mobile device to calculate its geolocation within $10\text{ meters}$.

Pairing

The procedure used to establish a secure wireless communication link between two Bluetooth devices.

Tethering

Connecting a mobile device to another mobile device or computer via Bluetooth, USB, or Wi-Fi to share its cellular internet connection.

Service Set Identifier (SSID)

A case-sensitive, alphanumeric network name up to 32 characters in length that identifies a specific wireless local area network (WLAN).

SSID Broadcast

A wireless router configuration setting that announces the network SSID publicly to nearby devices, which can be disabled to prevent neighbors from discovering the network name.

Guest SSID

A dedicated wireless network configuration allowing visitors to access the internet while isolating them from the local internal network.

Mixed Mode

A wireless router configuration that enables simultaneous connectivity for devices operating under different IEEE 802.11 standards (such as 802.11b, 802.11g, and 802.11n).

Standard Channel

The specific frequency channel over which wireless communications occur, typically configured to Auto to permit the access point to select the least congested channel.

WPA2 Encryption

A wireless security standard configured on a wireless router to encrypt wireless transmissions and block unauthorized devices from joining the network.

Internet Port (WAN Port)

The dedicated port on a home wireless router used to connect to an external service provider modem (such as a DSL or cable modem).

LAN Ports

The local Ethernet switch ports (typically numbered 1 to 4) on a home router used to connect wired hosts within the internal local network.

Network Protocol

A formal set of rules that defines how messages are formatted, transmitted, and handled between source and destination devices across a network.

Protocol Suite

A group of interrelated protocols that collectively provide all functions necessary for communication across various network layers.

Standards Organizations

Vendor-neutral regulatory and engineering bodies—such as IEEE, IANA, IETF, ICANN, ITU, and TIA—that define open industry standards to ensure interoperability.

Request for Comments (RFC)

Official memorandum documents published and maintained by the IETF that record, track, and standardize internet protocols.

Internet Engineering Task Force (IETF)

The international standards body responsible for the development, documentation, and publication of internet protocol specifications and RFC documents.

Institute of Electrical and Electronics Engineers (IEEE)

The professional standards organization responsible for defining Layer 1 and Layer 2 physical and wireless network specifications, including Ethernet ($802.3$) and Wi-Fi ($802.11$).

Protocol Model

A network communication model (such as the TCP/IP model) whose layers and architecture directly match the structure of an actual protocol suite.

Reference Model

A conceptual network model (such as the OSI 7-layer model) that defines the functions that must be completed at a particular layer without specifying exactly how each protocol should work.

OSI Physical Layer (Layer 1)

The OSI model layer responsible for the physical, electrical, optical, and procedural transmission of raw bits across a communication medium.

OSI Data Link Layer (Layer 2)

The OSI layer that controls media access, framing, physical (MAC) addressing, and Layer 2 error detection between devices on a common physical medium.

OSI Network Layer (Layer 3)

The OSI layer providing logical network addressing (such as IPv4 or IPv6) and path determination (routing) between identified end devices across networks.

OSI Transport Layer (Layer 4)

The OSI model layer that defines services to segment, transfer, track, and reassemble individual communications between end devices.

OSI Session Layer (Layer 5)

The OSI model layer that provides services to organize, manage, and synchronize dialogues and data exchange between presentation layer entities.

OSI Presentation Layer (Layer 6)

The OSI layer responsible for common representation, formatting, syntax, and data compression for application layer services.

OSI Application Layer (Layer 7)

The top layer of the OSI model, containing protocols utilized directly by software applications for process-to-process communication across a network.

TCP/IP Model

A 4-layer networking framework comprising Application, Transport, Internet, and Network Access layers that maps directly to the internet protocol suite.

TCP/IP Network Access Layer

The lowest TCP/IP layer, which maps directly to the combined functions of the OSI Physical and Data Link layers.

TCP/IP Internet Layer

The layer in the TCP/IP model functionally equivalent to the OSI Network layer, responsible for routing packets across an internetwork.

Twisted-Pair Cable

A common network cable featuring insulated copper wire pairs twisted together to reduce interference and crosstalk, used to connect office PCs to local switches.

Category 5e (Cat5e) Cable

A widely used twisted-pair Ethernet cable containing 4 wire pairs (8 conductors) terminated with RJ-45 connectors, designed for high-bandwidth LAN connectivity.

Coaxial Cable

A shielded copper cable featuring a solid central conductor surrounded by insulation, a braided metal shield, and an outer jacket, commonly used for cable television and satellite modem connections.

Fiber-Optic Cable

A high-speed, long-distance transmission medium constructed of flexible glass or plastic fibers that carries data as pulses of light with complete immunity to EMI and RFI.

Electromagnetic Interference (EMI) / RFI

Radio frequency and electrical noise that distorts signals traveling over copper cabling, to which fiber-optic cabling is completely immune.

Ethernet Frame

The Layer 2 protocol data unit that encapsulates network layer packets for transmission across local Ethernet networks.

Preamble and SFD

The initial fields of an Ethernet frame that synchronize bit timing and signal the exact beginning of the frame addressing fields.

Frame Check Sequence (FCS)

A 4-byte trailer field in an Ethernet frame used by the receiving node to perform a Cyclic Redundancy Check (CRC) and determine if bit errors occurred during transmission.

Media Access Control (MAC) Address

A unique 48-bit physical Layer 2 address permanently assigned by the manufacturer and burned into a device's Network Interface Card (NIC).

MAC Address Table

An internal switch database that stores mappings between learned source MAC addresses of incoming frames and their corresponding switch ports.

Unknown Unicast Flooding

The action taken by an Ethernet switch when receiving a unicast frame whose destination MAC address is not listed in its MAC table: forwarding the frame out all ports except the incoming port.

Ethernet Switch

A Layer 2 intermediary networking device that examines incoming frames and selectively forwards traffic based on entries in its MAC address table.

Ethernet Hub

An obsolete Layer 1 network device that lacks a MAC address table and indiscriminately repeats all incoming electrical signals out every other port.

IPv4 Address

A 32-bit logical hierarchical network address represented in dotted-decimal format across 4 octets, used to uniquely identify a device on an IP network.

Network Portion

The initial bits of an IPv4 address that identify the specific network or subnet where a device is located.

Host Portion

The trailing bits of an IPv4 address that uniquely distinguish a specific host on its assigned local network.

Subnet Mask

A 32-bit dotted-decimal number that, through bitwise logical ANDing with an IPv4 address, differentiates the network portion from the host portion.

Unicast Transmission

A communication mode in which data packets are sent from a single source host to a single unique destination host IP address.

Broadcast Transmission

A transmission mode in which a single packet is delivered to all devices residing within the same local broadcast domain.

Limited Broadcast Address

The IPv4 address $255.255.255.255$, used by hosts to broadcast to all devices on the local physical network without being forwarded across routers.

Directed Broadcast

A message sent to all hosts on a specific remote network, utilizing an IP address where all host bits are set to binary ones.

Multicast Transmission

A delivery mechanism where packets are sent to a reserved Class D multicast IP address ($224.0.0.0$ to $239.255.255.255$) to reach a subscribed group of hosts.

Public IPv4 Address

An IP address assigned by service registries that is globally routable across internet service provider routers.

Private IPv4 Address

Non-globally routable address blocks ($10.0.0.0/8$, $172.16.0.0/12$, and $192.168.0.0/16$) assigned to devices within an organization's internal intranet.

RFC 1918

The Internet Engineering Task Force standard defining the reserved private IPv4 address ranges used within private enterprise and home networks.

Loopback Address

A reserved IPv4 block ($127.0.0.0/8$, commonly $127.0.0.1$) used by a host to route test traffic back to its own internal TCP/IP stack without placing traffic on the network wire.

Link-Local Address (APIPA)

An automatic private IP address in the $169.254.0.0/16$ range assigned by an operating system when a host cannot contact a DHCP server.

Classful Addressing

The legacy IPv4 allocation scheme dividing addresses into Class A ($50\%$), Class B ($25\%$), Class C ($12.5\%$), and Class D & E ($12.5\%$).

Broadcast Domain

A logical network area containing all devices that receive any Layer 2 broadcast frame initiated within it, bounded and separated by routers.

Subnetting

The division of a larger network into smaller broadcast domains to minimize broadcast traffic, optimize performance, and implement security controls.

IPv6 Address

A 128-bit hierarchical network address represented as 32 hexadecimal values organized into 8 colon-separated 16-bit hextets.

Hextet

A 16-bit segment consisting of four hexadecimal values separated by colons in an IPv6 address.

Omitting Leading Zeros Rule

An IPv6 compression rule allowing any leading zeros in each 16-bit hextet to be removed (for example, converting $0\text{db}8$ to $\text{db}8$ and $0000$ to $0$).

Double Colon (::) Rule

An IPv6 abbreviation rule permitting a single contiguous string of one or more all-zero hextets to be represented once per address by a double colon (::).

Dual Stack

An IPv6 coexistence migration strategy where a host or router runs both IPv4 and IPv6 protocol stacks simultaneously on the same network adapter.

Tunneling

An IPv6 migration technique that encapsulates native IPv6 packets inside IPv4 headers to transport them across IPv4-only network infrastructures.

NAT64

A transition technology allowing IPv6-only devices to communicate with IPv4-only devices through packet header translation.

Regional Internet Registry (RIR)

Five regional organizations (ARIN, RIPE NCC, APNIC, LACNIC, and AfriNIC) that receive IP blocks from IANA and manage address distribution to ISPs.

Dynamic Host Configuration Protocol (DHCP)

A network service that dynamically configures host devices with IP addressing, subnet mask, default gateway, and DNS settings without manual configuration.

Static IP Assignment

The manual configuration of network addressing values by a network administrator, typically reserved for gateways, servers, and network printers.

DHCP Lease

The defined duration for which a client host is permitted to use an IP address allocated dynamically by a DHCP server.

DHCPDISCOVER

The initial broadcast message ($255.255.255.255$) transmitted by an unconfigured client seeking available DHCP servers on the local network link.

DHCPOFFER

A message sent by a DHCP server offering a specific IP address, subnet mask, and lease duration to a client that sent a DHCPDISCOVER.

DHCPREQUEST

A broadcast message sent by a client to accept an offered IP address and notify the offering DHCP server.

DHCPACK

A unicast message sent by a DHCP server confirming the accepted lease and granting final configuration parameters to the client.

DORA Process

The four-step DHCP address allocation exchange consisting of Discover, Offer, Request, and Acknowledgment.

Default Gateway

The IP address of the local router interface that allows computers on a local network to communicate with devices on other remote networks.

Binary ANDing

The mathematical operation performed by a host using its subnet mask to compare source and destination IP addresses and determine whether a target is local or remote.

Network Address Translation (NAT)

A routing process that translates internal private IPv4 addresses into one or more registered public IP addresses for internet communications.

Global Address (NAT)

The public IPv4 address assigned to a wireless router's internet (WAN) port by an ISP, which the router uses in NAT translations for internal client traffic.

Address Resolution Protocol (ARP)

A communication protocol used to resolve a known destination IPv4 address to its corresponding physical MAC address on a local Ethernet network.

ARP Table (ARP Cache)

A RAM cache maintained on a host that stores resolved pairs of destination IPv4 addresses and their corresponding MAC addresses.

ARP Request

A broadcast frame ($FF:FF:FF:FF:FF:FF$) sent by a host out all local switch ports inquiring which device owns a specific target IPv4 address.

ARP Reply

A unicast frame containing its MAC address sent back to the requester by the host whose IP matches the target address in an ARP request.

Broadcast MAC Address

The hexadecimal Layer 2 destination address $FFFF.FFFF.FFFF$ (48 one bits), which forces every device on the local network segment to receive and process the frame.