CompTIA A+ Core 1

LAN

Local Area Network; a geographic network that covers a relatively small geographic area such as a building or a small campus - no more than a mile distance between computers

PAN

Personal Area Network; Short range and typically associated with Bluetooth

NFC

Near Field Communication; Short distance networking, typically 4 centimeters or less, used for small amounts of data transfers or authentication

• Payment systems, transportation, access token/identity

Laptop Displays

LCD

Different LCD Technologies

TN (Twisted Nematic) LCD

• Original LCD Technology
• Fast Response Time (Gaming) I had a TN BenQ monitor
• Poor viewing angles - color shifts

OLED

Organic Light Emitting Diode

• Organic Compound emits light when receiving an electric current
• Thinner and lighter, flexible and mobile as there is no glass needed
• No backlight
• Tablets, Phones, Smartwatches
• Very accurate color representation
• A bit higher cost than LCD

WiFi Antennas

-The wires wrap around the laptop screen at the highest point
-Contains a main, aux, and bluetooth connection

Microphone

Built into laptop display

Fluorescent Back Lighting

CCFL - Cold Cathode Fluorescent Lamp

• Higher voltage and power needed
• Added thickness to the display
• No longer a common backlight
• needs an Inverter as the backlight requires AC power but the laptop uses DC

LED Back lighting

• Backlight is LEDs instead of florescent
• LEDs around the edge of the screen
• An array of LEDs behind the screen
• The latest laptops are LED-backlight

Backlight

• Use a flashlight and look closely to help determine if the backlight has went bad
• If you can see some of the information being displayed then the backlight may be bad instead of the display
• On older CCFL displays you may only need to replace the inverter

Digitizer

Not specifically a touchscreen, though a touchscreen is a special digitizer

• Use a pen-like device as input
  --Stylus input, useful for graphical design

Touchscreen

• Merge laptop and tablet input
  --Digitizer responds to touch now, no keyboard required but often still available, there are many options for input, use the best one for the job

Connecting Mobile Devices

USB

USB-C

24-Pin Double-sided USB connector

• Used for both hosts and devices

Lightning

Apple proprietary

• 8-pin digital signals

Serial Interfaces

DB-9

• Also called DE-9

Bluetooth

High speed communication over short distances

• PAN (Personal Area Network)

Mobile Device Accessories

Hotspot

Touch Pens

• Touchscreen pen / touch screen stylus / capacitive stylus

• Activate the interface without actually touching it

Active Stylus

• Digital stylus

• A more advanced writing tool

Drawing Pad

• Use an active stylus with an external digitizer

• Very precise input

Trackpad

• Replace the mouse

• Useful in tight working areas
• Common on laptops

Headsets

• Hands-free audio - Earphones and microphone

Speakers

• Mobile audio

• Battery powered

Camera / Webcam

• Internal or external

• Commonly external on desktops,
  internal on laptops/tablets/phones

Docking Station

• Docking station

• Use external keyboard and mouse
• Extend existing laptop interfaces
• Add additional functionality
• Desktop adapter cards
• Avoid cable issues

Port Replicator

• Port replicator

• Similar to a docking station
• Does not commonly have an expansion card option
• Usually connects using USB
• Can have other ports, not only USB

Cellular Standards

Cellular Networks

GSM

Global System for Mobile Communications

• Mobile networking standard

CDMA

• Code Division Multiple Access

• Everyone communicates at the same time
• Each call uses a different code
• The codes are used to filter each call on the
  receiving side

3G Technology

*3rd Generation
• Introduced in 1998

4G and LTE

• Long Term Evolution (LTE) - A "4G" technology

• Converged standard (GSM and CDMA providers)
• Based on GSM and
  EDGE (Enhanced Data Rates for GSM Evolution
• Standard supports download rates of 150 Mbit/s

5G

• Fifth generation cellular networking

• Launched worldwide in 2020

Updates

PRL updates

• preferred roaming list
• cdma networks (i.e. verizon, sprint)

Mobile Device Connectivity

Bluetooth Pairing

GPS (Global Positioning System)

Created by the U.S. Department of Defense
-Over 30 satellites currently in orbit

MDM (Mobile Device Management)

• Manage company-owned and user-owned mobile devices

• BYOD - Bring Your Own Device

MDM Configurations

• Corporate email configuration

• User does not need to configure anything
• The MDM makes the changes on the device
• Account details, server address, communication method

Mobile Device Configurations

Configuring a mobile device

Microsoft 365

Outlook, Exchange

• Microsoft's email service
• Usually the same for Hotmail and Outlook.com

iCloud

• Integrated into iOS and iPadOS

• Provide an iCloud username and password

Synchronizing Data

Data types

• Mail, Pictures, Music, Video, Calendar, Contacts

Introduction of IP

A Series of moving vans

IP - Internet Protocol

TCP and UDP

TCP - Transmission control protocol

• Connection-oriented

• A formal connection setup and close

UDP - User Datagram Protocol

• Connectionless

• No formal open or close to the connection

Why would you ever use UDP?

• Real-time communication

• There's no way to stop and resend the data
• Time doesn't stop for your network
• Used for online games and phone calls for example

Communication using TCP

• Connection-oriented protocols prefer a "return receipt"

• HTTPS (Hypertext Transfer Protocol Secure)
• SSH (Secure Shell) encrypted form of terminal communication between our systems

Speedy Delivery

• The IP delivery truck delivers from
one (IP) address to another (IP) address

• Every house has an address,
  every computer has an IP address

Lots of Ports

• IPv4 sockets

• Server IP address, protocol, server application port number
• Client IP address, protocol, client port number

Port Numbers

• TCP and UDP ports can be any number
between 0 and 65,535

Ports on the network

*Web server - tcp/80

Ports on the network (Cont)

Source port is chosen at random by the client device

Common Network Ports

Port Numbers #2

FTP - File Transfer Protocol

tcp/20 (active mode data),
tcp/21 (control)

• transfer files between systems with authentication
• tcp/21 is used to authenticate the connection
• tcp/20 is used to send the data across the connection

SSH - Secure Shell

• Encrypted communication link - tcp/22
• Looks and acts the same as Telnet
• Terminal / Command line front end used to connect to remote devices

• Allows you to securely transfer files between servers

Telnet

• Telnet - Telecommunication Network - tcp/23
• Login to devices remotely
• Console access
• In-the-clear communication (Not encrypted/secure)
• Not the best choice for production systems

SMTP - Simple Mail Transfer Protocol

• SMTP - Simple Mail Transfer Protocol

• Server to server email transfer
  • tcp/25

DNS - Domain Name System

• Converts names to IP addresses - udp/53
• www.professormesser.com = 162.159.246.164
• These are very critical resources
• Usually multiple DNS servers are in production

DHCP - Dynamic Host Configuration Protocol

• Automated configuration of IP address, subnet mask
and other options

• udp/67 for DHCP server, udp/68 for DHCP client
• Requires a DHCP server
  • Server, appliance, integrated into a SOHO router, etc.

HTTP and HTTPS

• Hypertext Transfer Protocol - tcp/80

• Communication in the browser
• And by other applications

POP3 / IMAP4

• Receive emails from an email server

• Authenticate and transfer

SMB - Server Message Block

Method of transferring files and information between devices using that operating system

SNMP - Simple Network Management Protocol

• Gather statistics from network devices

• Queries: udp/161 used to querie an infrastructure device for performance details and receive those metrics in return
• Traps: udp/162 configure infrastrucure device to monitor certain metrics, if it exceeds those metrics it will send an alert to the management station, or send a "Trap"

LDAP

LDAP (Lightweight Directory Access Protocol)

• tcp/389

RDP - Remote Desktop Protocol

• Share a desktop from a remote location over tcp/3389

Network Devices

SOHO Router

Routers

-Routes traffic between IP Subnets
-Makes forward decisions based on IP address
-Inside of switches called "Layer 3 Switches"
-Often connects diverse network types

• LAN, WAN, Copper, Fiber
  (Can connect a Serial WAN Link, a Ethernet copper connection and an Ethernet Fiber connection on same device)

Switch

bridging done in hardware

• Application-Specific Integrated Circuit (ASIC)
• Forwards traffic based on the destination MAC address
  Many ports and features
• The core of an enterprise network
• May provide PoE
  Multilayer Switch
• Includes routing functionality
• Also referred to as a layer 3 switch

Unmanaged Switch

• Very few configuration options

• Plug and play

Managed Switch

• VLAN support

• Interconnect with other switches via 802.1Q

Access Point

• Not a wireless router

• A wireless router is a router and an access point in a single device

Patch Panel

Combination of punch-down blocks and RJ-45 Connectors

Firewalls

• Filters traffic by TCP/UDP port number (OSI Layer 4 filtering)

• Some can filter based on the application (This would make it a layer 7 Firewall)

Power over Ethernet (PoE)

•Power provided on an ethernet cable
-One wire for both network and electricity
-Used for IP Phones, Wireless Access Points
-Useful in difficult-to-power areas

PoE Switch

• Power over Ethernet

• Commonly marked on the switch or interfaces

PoE, PoE+, PoE++

• PoE: IEEE 802.3af-2003

• The original PoE specification
• Now part of the 802.3 standard
• 15.4 watts DC power, 350 mA max current

Hub

• Multi-port repeater

• Traffic going into one port is repeated to every other port

Cable Modem

Provided by Cable Company

DSL Modem

Provided by Telephone company

ONT

Optical Network Terminal

• Fiber to the premises
• Usually connected outside your house

Network Interface Card (NIC)

• The fundamental network device

• Every device on the network has a NIC
• Computers, servers, printers, routers, switches, phones,
  tablets, cameras, etc.

Software Defined Networking

SDN (Software Defined Networking)

SDN (Software Defined Networking) Cont

*Infrastructure Layer / Data plane

• Process the network frames and packets
• Forwarding, trunking, encrypting, NAT

SDN Data flows

Wireless Network Standards

Wireless standards

802.11a

• One of the original 802.11 wireless standards

• October 1999