IT:AD:Subnets

A MAC address is hardware based
An IP address is:
- Composed in software
- Composed of 4 Octets
- Composed of two parts: Network + Host
- Subneting from the firs tpart of the Host portion.
Types of Addressing:
- IPv4
  - 4.3 billion IPs
  - IP = 32 bytes (4 x 8bits, which are Octets)
  - Running out.
- IPv6
  - 2^128 (3.4028237e+38)
Grouped as Networks
- For More efficient routing.
- The “Network Address” is the Address of the network (eg: 172.16.1.0), ending with 0.
Classes:
- A:
  - Big:
  - First Octet: 1-126
  - Subnet Mask: 255.0.0.0 (8 bits)
  - Number of Networks: 126
  - Number of Hosts/Network: 16,777,214
  - as for 127, see below for loopback.
  - B:
  - Medium:
  - First Octet: 128-191
  - First 2 dedicated to Network
  - Last 2 dedicated to Host portion
  - Subnet Mask: 255.255.0.0 (16 bits)
  - Number of Networks: 16,382
  - Number of Hosts/Network: 65,524
  - C:
  - Small:
  - First octet: 192-223
  - Subnet Mask: 255.255.255.0 (24 bits)
  - Number of Networks: 2,097,150
  - Number of Hosts/Network: 255
  - D:
  - Multicasting
  - First octet value range from 224 to 239
  - 224.0.0.0 to 239.255.255.255
  - Number of Networks: N/A
  - Number of Hosts/Network: Multicasting
  - So you have to remember - 0-127-192-224-239
  * 127.0.0.0 - 127.255.255.255
- Loopback range
  - Eg: 127.0.0.1
  - Used to test that the Network card is working.
Examples:
- 172.16.0.0/16
  - Gives: 65,524 Hosts