CompTIA Network+ (Ch.7)

Unmanaged switch

A plug-and-play switch with few configuration options and no IP assigned

Managed switch

A switch that can be configured through a CLI or web GUI

Layer 2 switch

A switch that forwards traffic using Layer 2 information

Layer 3 switch

A switch that can route traffic like a router

Layer 4 switch

A switch that interprets Layer 4 data

STP (Spanning Tree Protocol)

Prevents switching loops by blocking links that would create a loop

BPDUs

Bridge Protocol Data Units, messages used by STP

Unused switch ports

Should be disabled until needed to prevent unauthorized access

switchport port-security

Uses MAC filtering to help protect against MAC flooding

Defense in depth

Using multiple layers of security

Redundancy

Multiple paths or resources that reduce vulnerability to hardware failures

RSTP

Rapid Spanning Tree Protocol, a newer version of STP

TRILL

An alternative technology to STP

SPB

Shortest Path Bridging, an alternative to STP

Access layer

The layer where switches connect directly to end devices

Distribution layer

Connects access layers through redundant connections between network devices

Core layer

Provides efficient forwarding of backbone traffic

East-west traffic

Peer-to-peer traffic within a network segment

North-south traffic

Traffic leaving the local network segment

Spine-and-leaf architecture

Uses spine switches connected to all leaf switches, but not to each other

ToR

Top-of-rack switching

EoR

End-of-row switching

Availability

How consistently or reliably a system or file can be accessed

High availability (HA)

Reliable system access nearly all the time

Uptime

The duration a system functions normally between failures

Fault tolerance

The ability to continue operating despite unexpected hardware or software malfunctions

Fault

A component malfunction

Failure

A deviation from specified system performance over time

Link aggregation

Combines multiple network interfaces or ports into one logical interface

NIC teaming

The Windows term for combining multiple network interfaces

Port aggregation

The Unix and Linux term for combining network ports

Link aggregation benefits

Higher throughput, automatic failover, and load balancing

Load balancer

Distributes traffic among multiple devices

Clustering

Groups redundant resources so they appear as one device

VIP (Virtual IP)

An IP address clients use to access a group of redundant resources

Virtualization

Creating a virtual or logical version of a physical resource

Host

The physical computer that runs virtual machines

Guest

A virtual machine running on a host

Hypervisor

Software that creates and manages virtual machines

Type 1 hypervisor

A bare-metal hypervisor that runs directly on physical hardware

Type 2 hypervisor

A hosted hypervisor that runs as an application inside an existing operating system

vNIC

A virtual network interface card that operates at Layer 2

vSwitch

A virtual switch that connects virtual machines and networks

Bridged mode

The VM connects through the host's physical network and gets its own LAN IP configuration

NAT mode

The host acts as a NAT device and provides the VM's IP configuration

Host-only mode

VMs and the host can communicate, but traffic cannot go beyond the host

Virtualization advantages

Efficient resource use, lower costs and energy use, isolation, and easier backups and recovery

Virtualization disadvantages

Possible performance loss, complexity, licensing costs, and a single point of failure

NFV (Network Functions Virtualization)

Runs network functions as virtualized services that can migrate and scale

SDN (Software-Defined Networking)

Centralizes network decisions and configuration through software

SDN data or infrastructure plane

Physical and virtual devices send and receive messages

SDN control plane

Makes network decisions

SDN application plane

Allows the SDN controller to communicate with applications through APIs

SDN management plane

A plane that may be included as part of the control plane

Cloud computing

Provides flexible storage, applications, and services to clients over a network

On-demand service

Cloud resources are available when requested

Broad network access

Cloud services can be accessed over a network by different client devices

Resource pooling

A provider shares computing resources among multiple clients

Metered service

Cloud resource usage is measured

Rapid elasticity

Cloud capacity can scale up or down as needed

IaaS

Infrastructure as a Service, provides virtualized hardware and network infrastructure

PaaS

Platform as a Service, includes the operating system, runtime components, and underlying hardware

SaaS

Software as a Service, provides applications to users

XaaS

Anything as a Service, combines services based on client needs

Shared responsibility model

The cloud provider and customer divide responsibility for cloud resources

On-premises

Hardware and software are located and managed at the organization's site

Public cloud

Cloud services provided over public transmission lines

Private cloud

Cloud services established on an organization's own servers and data center

Community cloud

A cloud shared by multiple organizations

Hybrid cloud

A combination of public and private cloud resources

Multicloud

A deployment combining multiple cloud service models, as described in the slides

Cloud management tools

GUI portal, CLI, SDK, and API

Cloud compute services

Cloud services that provide computing resources such as virtual machines

Cloud networking services

Cloud services that provide network resources

Cloud storage services

Cloud services that store data

Cloud security services

Cloud services that protect cloud resources

Dynamic inventory

Infrastructure that adapts to changes, inputs, or criteria

IaC (Infrastructure as Code)

Uses text-based configuration files to create and manage infrastructure

Automation

A programmed computer response to a specific event

Orchestration

Automates multiple tasks together in a complex workflow

Playbook

A template that defines the sequence of an automated workflow

Automation and orchestration benefits

Improved responsiveness, control, cost efficiency, security, and repeatability

Source or version control

Tracks code changes so they can be tested, integrated, and reversed

Central repository

Stores authoritative code versions, including production versions

Branch

A separate copy of code used for development or testing

Commit

Saves or uploads changes into a branch