Index

COMPUTER NETWORKING

  1. INTRO
    1. TCP/IP Five Layer Model
    2. NETWORKING DEVICES
    3. PHYSICAL LAYER
    4. DATALINK LAYER
  2. NETWORK LAYER
    1. IP
    2. SUBNET
    3. ROUTING
  3. TRANSPORT & APPLICATION LAYER
    1. TRANSPORT LAYER
    2. CONTROL FLAGS
    3. APPLICATION LAYER
    4. ALL TOGETHER
  4. NETWORK SERVICES
    1. DNS - NAMES RESOLUTION
    2. DHCP
    3. NAT
    4. VPN
  5. CONNECTING TO INTERNET
    1. BROADBAND
    2. WAN
    3. WIRELESS NETWORKING
  6. TROUBLESHOOTING
  7. MORE ABOUT
    1. DNS
    2. IPv6
    3. CLOUD

WIRELESS NETWORKING

Frequency Band: A certain section of the radio spectrum that's been agreed upon to be used for certain communications.
2.4 and 5GHz

802.11 -> protocol that operates datalink and network layers
802.11b
802.11g
802.11n
802.11ac

Higher access speeds, device accessibilities
802.11 Frame:
images/25-1.png
4 addresss fields
https://en.wikipedia.org/wiki/IEEE_802.11

Wireless Access Point : bridges wired and wireless parts

Wireless Network Configurations:
• Ad-hoc Networks : Nodes all speak directly ex: exchanging photos, videos
During disaster situations. If all infrastructure is down This can be used as SOS.
images/25-2.png

• Wireless LANS (WLANS): One or more access points acts as a bridge
Most Common.
images/25-3.png

• Mesh Networks : hybrid
images/25-4.png


WIRELESS CHANNELS: Individuals, smaller sections of the overall frequency band used by a wireless network.
Avoids collision domains.
802.11b -> 1,6,11 dont interfere
images/25-5.png

WIRELESS SECURITY:
WEP (wired equivalent policy): really weak security

WPA/WPA2(Wireless Protected Access) 128bit
• Developed by Wi-Fi Alliance
• WPA2 uses AES (Advanced Encryption Standard)

WPA2-PSK(Pre-Shared Key) 256 bit key
• Provide a plain english passphrase btwn 8-63 charactersWPA/WPA2(Wireless Protected Access)
• Developed by Wi-Fi Alliance
• WPA2 uses AES (Advanced Encryption Standard)

MAC FILTERING : access points only to allowed devices

CELLULAR NETWORKING:
Common iwth 802.11
Uses radio waves
Longer distances.
Built on concept of cells specific frequencies.
Cell towers : ACcess points
WIFI
IOT protocols