CompTIA A+ 220-1201 Exam Prep - 3rd Set of Videos

RFC 1918 Range: 10.0.0.0 - 10.255.255.255

The 'big' private IP range supporting approximately 16 million addresses.

RFC 1918 Range: 172.16.0.0 - 172.31.255.255

The 'middle' private IP range supporting approximately 1 million addresses.

RFC 1918 Range: 192.168.0.0 - 192.168.255.255

The common home router private IP range supporting 65,536 addresses.

Octet

A grouping of 8 bits (1 byte) with a maximum decimal value of 255.

IPv6 Address Format

128-bit address expressed in hexadecimal and separated by colons.

NAT (Network Address Translation)

Technology allowing multiple local devices to share a single public IP address.

169.254.x.x

APIPA address; indicates the DHCP server is unreachable or not responding.

Subnet Mask

Determines if a destination IP is local or requires the default gateway.

Default Gateway

The local router used to communicate with devices outside the local subnet.

ARP (Address Resolution Protocol)

Protocol used to check if an IP address is already in use on the network.

Rain Fade

Degradation of satellite signals caused by heavy precipitation/weather.

ADSL (Asymmetric Digital Subscriber Line)

DSL where download speeds are different (usually faster) than upload speeds.

DSL Distance Limit

Approximately 10,000 feet from the central office (CO).

Satellite Latency

500ms for traditional geostationary; 25-60ms for Low-Earth Orbit (Starlink).

Broadband

Multiple signals/frequencies sharing one medium simultaneously (e.g., Cable TV).

SAN (Storage Area Network)

Network providing block-level access that appears as a local drive to servers.

NAS (Network Attached Storage)

Network storage providing file-level access, appearing as a network share.

MPLS (Multiprotocol Label Switching)

Uses short labels for fast forwarding decisions instead of full IP table lookups.

MAN (Metropolitan Area Network)

A city-scope network, often utilizing Metro Ethernet or municipal fiber.

Terrestrial vs. Non-Terrestrial

Terrestrial refers to land-based connections; non-terrestrial refers to satellite.

The Flashlight Test

Used to diagnose backlight failure; faint image visible under external light.

Inverter

Component that powers older CCFL (fluorescent) backlights; not used in LED displays.

TN (Twisted Nematic) Panel

Display type preferred for gaming due to fast response times.

IPS (In-Plane Switching) Panel

Display type preferred by graphic designers for superior color accuracy.

VA (Vertical Alignment) Panel

A budget-friendly display type offering decent color and contrast.

OLED vs. Mini LED

OLED is self-lit per pixel; Mini LED uses LCD with tiny backlight zones.

PPI Formula

Pixels ÷ Inches; determines the sharpness of a display.

V-sync

Configuration that links GPU frame output to monitor refresh rate to prevent tearing.

sRGB

The common baseline color gamut standard for most displays.