Monday, May 23, 2016

IT2 Chapter 3 Notes - Networking / Hardware

Greetings, and welcome to Seeseenayy.
Below are the chapter 3 notes for IT. I can't remember what the name of it was, but I was told it was networking and hardware.

IT2 CHAPTER 3
NETWORKING & HARDWARE (Minor)





    Monitors:
  • CRT - Cathode Ray Tube
    • Issues: Heavy, Big, Stores Electricity
    • Maintains voltage after unplugging.
  • LCD - Liquid Crystal Display
  • LED - Light Emitting Diode


Pixels (Image on the right), known as RBG (colors).
Dot Pitch is known as the distance per pixel.



Resolutions:
  • VGA
    • 640x480, is 4:3
  • SVGA
    • 800x600, is 4:3
  • XGA
    • 1024x768,      is 4:3
  • HDTV
    • 1920x1080,    is 16:9

Refresh Rate - The frequency with which a monitor's display is updated.


Refreshes via two methods:
  • Interlaced
    • Refreshes the odd lines first, then even.
  • Non Interlaced
    • Starts at the first line, goes to the last.


PC HARDWARE - WHAT TO KNOW BEFORE PURCHASING!


Consider these when purchasing a component...
Motherboard:
  • CPU & Form Factor
  • Expansion (EXT/INT)
  • Amount of RAM the motherboard will hold.


CPU:
  • Socket
  • Cores
  • Speed
  • Power
  • Heat


RAM:
  • Type
  • Capacity


HDD:
  • Type (SSD/SAS/SATA/PATA)
  • Capacity
  • Speed


OPTICAL DRIVE:
  • Type (SATA/PATA)
  • Supported


ADDON CARDS:
  • What is needed to add on to? (Video? Sound? Storage?)
  • External Storage:
    • Type, Connections, Power, Capacity, & Size
  • Input/Output Devices


Why use a network?
  • Centralized Storage
  • Centralized Administration
  • Fewer Peripherals (Printers, etc)


Two kinds of networks:
  • Peer to Peer
  • Client / Server


Measures of network speed:
  • Half - Duplex
  • Full - Duplex


Mac/IP Addressing (IP Address)
  • (IPv4) Logical Address
  • Uses 32 bits
  • Dotted decimal format.
  • 4 groups of 3 digits.
  • Software based.


Mac/IP Addressing (MAC Address)
  • Physical Address
  • Uses 48 bits.
  • Hexadecimal
  • 6 groups of 2
  • Hardware based


Classes of IPv4
CLASS PUBLIC PRIVATE SUBNET
A
  • Used for very large networks.
  • 0.0.0.0 to 127.255.255.255     10.0.0.0 - 10.255.255.255   255.0.0.0
B
  • Used for medium networks.
  • 128.0.0.0 to 191.255.255.255     172.16.0.0 - 172.31.255.255 255.255.0.0
C
  • Used for small networks like LANs.
  • 192.0.0.0 to 223.255.255.255     192.168.0.0 - 192.168.255.255 255.255.255.0
D
  • Used for multicast scenarios.
  • Not used by us this year.
  • 24.0.0.0 to 239.255.255.255
E
  • Experimental.
  • Not used by us this year.
  • 240.0.0.0 to 247.255.255.255


Addressing
Static - IP/SM/DGW/DNS


CHAPTER 3
Network Components
Modem - Cable, DSL, Modulate and Demodulate
Switch - Connects computers. 4 to 48 port switch. It will (mostly) go to a router / WAP.
Router (WAP) - Provides wifi access and connections network.
Multi Purpose Devices - (Wifi) router + switch, (modem/wifi/switch)
NAS - Network Attached Storage
VOIP Phone - Voice Over IP Phone
Hardware Firewall - Faster, physical firewall.


Cables - RJ-45 (Ethernet), Fiber Optic, Coaxial (RG-59)
Cost, Secure, Expansion, Wireless, & Wire


Cable Types:
  • Coax (RG-59)
  • Twisted Pair (RJ-45)
  • Unshielded Twisted Pair (UTP)
  • Shielded Twisted Pair (STP)


Cable Ratings:
Cat 5 - 100 MB/s - 100 Mhz
Cat 5e - 1000 MB/s - 100 Mhz
Cat 6 - 1000 MB/s - 250 Mhz
Cat 7 - 10 Gb/s - 600 Mhz


Straight-Thru-Both ends are the same! (Patch Cable)


Crossover - 1 end (T568A/T568B)
  • Connect like devices.


Rollover - 1 end (T568B Pins 1-8 & 8-1)


Connectors
  • SC
    • Snap-in Connector (2.5 mm)
  • ST
    • Bayonet Mount (2.5 mm)
  • LC
    • Snap-in Connector (1.25 mm)


2 Types of Cables
Single Mode - Up to 100 km lasers. (Not the bottom one)
Multi-Mode - Up to 2 km LEDs.  (--------------->)




TOPOLOGIES






       STAR MESH                RING                 BUS

Ethernet:
IEEE 802.1
IEEE 802.11


NAT - Network Address Translation

Static Address:
  • IP/SM/DGW/DNS
  • Manual

DHCP Address:
  • Automatic

Protocols:       https://www.grc.com/port_80.htm
  • 20 / 21
    • FTP
  • 23
    • Telnet/SSH
  • 53
    • DNS
  • 80
    • HTTP / Web

ISP Connections Advantages Disadvantages
  1. POTS Available Slow
  2. IDSN Better Speeds Slow
  3. DSL/ASDL Low Cost Distance from CO
  4. Cable High DL Speeds Slow Upload
  5. Satellite Remote Access Very Expensive
  6. Cellular Mobile Users Dead Zones


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