net+ domain 2 : network implementation

show version

Cisco IOS command that displays software version, uptime, hardware, interfaces, and related system information.

show interfaces

Cisco command that displays interface status, traffic counters, errors, and operational details.

show startup-config

Cisco command that displays the saved startup configuration.

show running-config

Cisco command that displays the current active configuration.

show cdp neighbors

Cisco command that displays directly connected Cisco devices discovered through CDP.

CDP

Cisco Discovery Protocol; Cisco Layer 2 protocol used to discover neighboring Cisco devices.

ping

Command that tests IP reachability using ICMP Echo Request and Echo Reply messages.

traceroute

Command that shows the Layer 3 path or hops toward a destination.

Privileged EXEC Mode

Cisco command mode indicated by # and entered using enable.

enable

Cisco IOS command used to enter privileged EXEC mode.

ROM

Read-only memory storing low-level bootstrap or startup code on a network device.

IOS

Cisco Internetwork Operating System used on many Cisco networking devices.

Interface

Physical or logical network connection on a device.

FastEthernet

Ethernet interface operating at up to 100 Mbps.

Gigabit Ethernet

Ethernet interface operating at 1 Gbps.

Serial Interface

WAN-style interface historically used for serial point-to-point links.

VPN Module

Hardware or software component that provides VPN processing capability.

Port Mirroring

Switch feature that copies traffic from one port to another for monitoring.

SPAN

Switch Port Analyzer; Cisco term for port mirroring.

Mirror Source

Port whose traffic is copied during a mirror session.

Mirror Destination

Port receiving copied traffic during a mirror session.

Rx

Receive direction; traffic entering a network interface.

Tx

Transmit direction; traffic leaving a network interface.

IDS

Intrusion Detection System; monitors network traffic for suspicious activity and raises alerts.

VLAN 1

Default VLAN on many switches.

Port VLAN Membership

Assignment of switch ports or LAGs to VLANs.

Link Aggregation

Combining multiple physical links into one logical connection.

LAG

Link Aggregation Group; logical bundle of multiple physical switch links.

LACP

Link Aggregation Control Protocol; IEEE-standard protocol used to dynamically negotiate aggregated links.

Static Link Aggregation

Link aggregation configured manually without dynamic LACP negotiation.

LACP Active

Mode that actively initiates LACP negotiation.

LACP Passive

Mode that waits for another device to initiate LACP negotiation.

NIC Teaming

Combining multiple server network adapters for redundancy and/or higher aggregate throughput.

Failover

Automatic switch to a backup link or component when the active one fails.

Failback

Return to the original or preferred link after it recovers.

Access VLAN Mode

Switch interface mode where the port or LAG belongs to one VLAN and sends endpoint traffic untagged.

Access Port

Switch port assigned to one VLAN, usually for endpoint devices.

Tagged Port

Port that transmits frames with an 802.1Q VLAN tag.

Untagged Port

Port that sends frames without a VLAN tag, typically to devices in one access VLAN.

Trunk Port

Switch port that carries multiple VLANs using VLAN tags.

802.1Q

IEEE VLAN tagging standard used on Ethernet trunk links.

WPA3

Newer Wi-Fi security standard improving authentication and management-frame protection.

SAE

Simultaneous Authentication of Equals; WPA3 authentication method replacing traditional PSK exchange.

PAKE

Password-Authenticated Key Exchange; cryptographic method allowing authentication using a password without exposing it.

PMK

Pairwise Master Key; keying material used to derive session encryption keys in Wi-Fi security.

PSK

Pre-Shared Key; shared password or key used in Personal Wi-Fi security.

WPA2

Wi-Fi security standard commonly using AES/CCMP and the four-way handshake.

WPA2 Four-Way Handshake

Exchange used to confirm key possession and derive/install session encryption keys.

PMF

Protected Management Frames; protects Wi-Fi management frames against spoofing or tampering.

RC4

Stream cipher used by WEP and early WPA/TKIP; considered insecure.

TKIP

Temporal Key Integrity Protocol; legacy WPA security protocol considered obsolete.

WEP

Wired Equivalent Privacy; outdated and insecure Wi-Fi encryption standard.

Routing Table

Table containing known routes and next-hop information used to forward packets.

Longest Prefix Match

Routing rule that selects the most specific matching route.

Prefix

Network portion of an IP route, represented by slash notation such as /24.

Administrative Distance

Measure of route-source trust; lower values are preferred for otherwise identical destination prefixes.

Destination Network

Target network listed in a routing table entry.

Static NAT

Permanent one-to-one mapping between private and public IP addresses.

Dynamic NAT

Temporarily maps private addresses to available addresses from a public pool.

NAT

Network Address Translation; converts addresses between private and public networks.

PAT

Port Address Translation; allows many private devices to share one public IP using unique port mappings.

Port Forwarding

Directs traffic arriving on a public port to a specified internal host and port.

DNS

Domain Name System; resolves hostnames to IP addresses and stores related records.

DNS A Record

DNS record mapping a hostname to an IPv4 address.

DNS CNAME Record

DNS record creating an alias from one hostname to another hostname.

Multicast

One-to-many communication sent from one sender to a selected group of receivers.

Wi-Fi 5

802.11ac; Wi-Fi generation operating primarily in the 5 GHz band.

802.11ac

IEEE wireless standard marketed as Wi-Fi 5.

2.4 GHz

Frequency band with longer range and better wall penetration but usually more interference.

5 GHz

Frequency band with more channels and higher potential speeds but less range and penetration than 2.4 GHz.

6 GHz

Newer Wi-Fi spectrum used by Wi-Fi 6E and Wi-Fi 7 capable devices.

Wi-Fi 6

802.11ax; operates in 2.4 GHz and 5 GHz.

Wi-Fi 6E

Wi-Fi 6 extended into the 6 GHz band.

WPA-Personal

Personal Wi-Fi security mode using a shared password or pre-shared key.

WPA2-Personal

WPA2 mode using a shared PSK.

WPA-Enterprise

Enterprise Wi-Fi mode using centralized authentication with older WPA security.

WPA2-Enterprise

WPA2 mode using 802.1X and EAP with centralized authentication.

802.1X

Port-based access control framework used for enterprise wired and wireless authentication.

RADIUS

Remote Authentication Dial-In User Service; centralized AAA protocol commonly used with 802.1X.

EAP

Extensible Authentication Protocol; framework supporting multiple authentication methods.

AAA

Authentication, Authorization, and Accounting; framework for controlling and auditing access.

Captive Portal

Web page requiring login, code entry, or terms acceptance before network access is granted.

MAC Address Filtering

Allows or blocks devices based on MAC address.

MAC Address

Layer 2 hardware address identifying a network interface.

Digital Certificate

Cryptographic credential used to verify identity and support secure communications.

Wi-Fi Encryption Method

Security protocol or cipher used to protect wireless traffic.

UPS

Uninterruptible Power Supply; provides temporary backup power during an outage.

PDU

Power Distribution Unit; distributes electrical power to multiple devices.

MTBF

Mean Time Between Failures; average expected operating time between failures.

MTTR

Mean Time to Repair; average time needed to restore a failed system.

Session Key

Temporary cryptographic key used to encrypt a specific communication session.

Enterprise Authentication

Centralized user-based authentication often using 802.1X, EAP, and RADIUS.

SNMP

Simple Network Management Protocol; used to monitor and manage network devices.

SNMP Community String

Shared text credential used by SNMPv1/v2c for access control.

DHCP

Dynamic Host Configuration Protocol; automatically assigns IP configuration to clients.

DHCP Lease

Temporary assignment of an IP address and related settings to a client.

DHCP Lease Negotiation

Process where a DHCP client and server exchange messages to assign network configuration.

802.11ac Beamforming

Wi-Fi technique that directs radio energy toward a client to improve signal quality.

Beamforming

Wireless technique that focuses RF energy toward a receiving device.

LACP Active Mode

LACP mode that sends negotiation messages and initiates aggregation.