CCNA Study guide

Devices that forward packets between networks and determine the best path based on routing tables

Routers

Layer 2 switch

A switch that forwards frames based on MAC addresses and operates at the data link layer

Layer 3 switch

A switch capable of routing packets using IP addresses and operating at both layer 2 and layer 3

Next

generation firewall (NGFW)

IPS

Intrusion Prevention System; monitors network traffic and can block malicious activity

Access points

Devices that provide wireless connectivity to clients in a network

Controllers (Cisco DNA Center and WLC)

Centralized devices for managing network policies, AP configurations, and monitoring wireless networks

Endpoints

Devices that connect to the network, such as PCs, phones, and IoT devices

Servers

Computers that provide services or resources to clients over a network

PoE

Power over Ethernet; allows network cables to deliver electrical power to devicesTwo

Three

tier topology

Spine

leaf topology

WAN topology

Wide area network connecting geographically dispersed networks

SOHO

Small office/home office network, typically small

On

premise

Cloud

Network services hosted externally by a service providerSingle

Multimode fiber

Fiber optic cable suitable for shorter distances with multiple light paths

Copper cabling

Physical network medium using twisted

Ethernet shared media

Network connections where multiple devices share the same medium

Point

to

Collisions

Occur when two devices transmit simultaneously on the same network segment

Errors

Corrupted or lost frames due to noise or hardware issues

Duplex mismatch

Occurs when two devices operate at different duplex modes (half/full)

Speed mismatch

Occurs when connected devices operate at different speeds

TCP

Transmission Control Protocol; connection

UDP

User Datagram Protocol; connectionless, faster, does not guarantee delivery

IPv4 addressing

Assigning unique 32

Subnetting

Dividing an IP network into smaller subnetworks for efficient IP management

Private IPv4 addressing

IP addresses reserved for internal networks (e.g., 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16)

IPv6 addressing

Assigning 128

IPv6 prefix

The network portion of an IPv6 address, used for routing

Unicast (IPv6)

Address assigned to a single interface, including global, unique local, and link

Anycast (IPv6)

Address assigned to multiple interfaces, with packets delivered to the nearest interface

Multicast (IPv6)

Address representing a group of interfaces, delivering packets to all members

Modified EUI

64

IP parameters verification (Client OS)

Checking IP configuration such as IP address, subnet mask, default gateway, and DNS on Windows, Mac OS, or Linux

Nonoverlapping Wi

Fi channels

SSID

Service Set Identifier; the name of a wireless network

RF

Radio Frequency; used for wireless signal transmission

Encryption (wireless)

Method to secure wireless communications using protocols like WPA2 or WPA3

Server virtualization

Running multiple virtual machines on a single physical server

Containers

Lightweight, portable software environments for applications

VRFs

Virtual Routing and Forwarding; allows multiple separate routing tables on the same device

MAC learning

Switch process of associating MAC addresses with physical ports

MAC aging

Removing inactive MAC addresses from the switch table after a timer expires

Frame switching

Forwarding a frame based on the destination MAC address

Frame flooding

Sending a frame out all ports except the one it arrived on when the destination MAC is unknown

MAC address table

Switch database mapping MAC addresses to switch ports

Configure VLANs (normal range)

Setting up VLAN IDs on switches, typically 1

Access ports (data and voice)

Switch ports assigned to a single VLAN for end devices; voice VLANs support IP phones

Default VLAN

VLAN 1; initial VLAN on Cisco switches

InterVLAN connectivity

Routing between VLANs to allow communication across VLANs

Trunk ports

Switch ports configured to carry traffic for multiple VLANs

802.1Q

VLAN tagging protocol used on trunk links to identify VLAN traffic

Native VLAN

VLAN assigned to untagged traffic on a trunk port

Cisco Discovery Protocol (CDP)

Cisco proprietary Layer 2 protocol for device discovery

Link Layer Discovery Protocol (LLDP)

Vendor

EtherChannel (LACP)

Logical bundling of multiple physical links between devices for increased bandwidth and redundancy

Rapid PVST+

Cisco Spanning Tree Protocol providing rapid convergence and separate instances per VLAN

Root port

Port on a switch closest to the root bridge, used to reach the root

Root bridge

Switch elected as the reference point in Spanning Tree; primary or secondary based on priority

Other port names

Designated ports, blocked ports, etc., in Spanning Tree topology

Port states

Forwarding, blocking, listening, learning, disabled

PortFast

Feature to immediately bring access ports into forwarding state, bypassing STP delays

Root guard

STP feature to enforce root bridge placement

Loop guard

STP feature to prevent loops on non

BPDU filter

Prevents sending or receiving BPDUs on a port

BPDU guard

Shuts down a port if BPDUs are received

Cisco Wireless Architectures

Centralized (controller

AP modes

Local, FlexConnect, Sniffer, Monitor, Rogue Detector

WLAN physical connections

AP connected to switch via access/trunk ports; WLC connected via LAG for redundancy and bandwidth

Network device management access

Methods to connect and manage devices: Telnet, SSH, HTTP, HTTPS, console

TACACS+/RADIUS

AAA protocols for authentication, authorization, and accounting

Cloud

managed devices

Wireless LAN GUI configuration

Using web

Routing protocol code

Letter in routing table indicating the source protocol of a route (e.g., O for OSPF, C for connected)

Prefix

Network portion of an IP address in the routing table

Network mask

Defines which portion of an IP address is network vs. host

Next hop

IP address or interface used to reach the destination network

Administrative distance

Value representing trustworthiness of a routing source; lower is more trusted

Metric

Value used by routing protocols to select the best path

Gateway of last resort

Default route used when no specific route matches

Longest prefix match

Router selects the route with the most specific subnet mask

Routing protocol metric

Metric used to choose the best path within a routing protocol

Static route

Manually configured route on a router

Default route

Route used for all unknown destinations

Network route

Static route for a network

Host route

Static route for a single IP address

Floating static

Static route with higher administrative distance than dynamic routes, used as backup

OSPF neighbor adjacency

Relationship established between OSPF routers for routing updates

Point

to

Broadcast

OSPF network type supporting DR/BDR elections

Router ID

Unique 32

First Hop Redundancy Protocol (FHRP)

Provides default gateway redundancy (e.g., HSRP, VRRP, GLBP)

Inside source NAT

Translates private addresses to public addresses for outbound traffic

Static NAT

One

NAT pools

Group of public IP addresses used for dynamic NAT

NTP client/server

Protocol and configuration to synchronize device clocks

DHCP

Assigns IP addresses and network parameters automatically

DNS

Resolves hostnames to IP addresses