Internet-Protocol-Address

Types of Addressing

Classful Addressing

  •  IPv4 uses concept of classes. This architecture is called classful addressing
  •  Types of Classes
                                Class A, B, C, D, and E.
  •  In Classful addressing, a large part of available addresses were wasted.
               
  •  IPv4 Addresses are divided into two parts
                                Netid ( Network ID ) defined by IANA (Internet Assigned Number Authority)
                                Hostid ( Host ID ) defined by ISP (Internet Service Provider)
From the above diagram

Class A

  •   First 8 bits are Netid and rest 24 bits are Hostid
  •   Each Hostid varies from 0-255 => 256 Nodes
  •   Subnet Mask is 255.*.*.* or 255.0.0.0
  •   Total No. of nodes can be connected = 256 * 256 * 256 = 16,777,216
  •   IPv4 Netid Range Varies: 0 – 127
                Eg.  10.0.0.0/8  – Starting and Ending IP Range 
 
 
 
  • Mask is over only 1st 8 bits
  • That means only first 8 bits (Netid) are fixed (varies from 0-127) assigned by IANA (Internet Assigned Number Authority) for Big Organizations having large no. of hosts attached.
  • Rest 24-Bits (3-Bytes Hostid) can vary from (0-255)
  • It implies that with single Netid there can be (256*256*256 = 16,777,216) nodes attached

Class B

  •    First 8 bits are Netid and rest 24 bits are Hostid
  •    Each Hostid varies from 0-255 => 256 Nodes
  •    Subnet Mask is 255.255.*.* or 255.255.0.0
  •    Total No. of nodes can be connected = 256 * 256 = 65,536
  •    IPv4 Netid Range Varies: 128-191
                Eg.  172.16.0.0/16 – Starting and Ending IP Range 
  • Mask is over only 1st 16 bits
  • That means only first 8 bits (Netid) are fixed (varies from 0-127) next 8 bits can be varying from (1-255)
  • These 16-Bits (2 Bytes Netid) are defined by IANA (Internet Assigned Number Authority) for mid size organizations with around ten thousands of hosts or router are attached
  • Rest 16-Bits (Hostid) can vary from (0-255)
  • It implies that with single Netid there can be (256 * 256 = 65,535)

Class C

  •   First 8 bits are Netid and rest 24 bits are Hostid
  •    Each Hostid varies from 0-255 => 256 Nodes
       
  •    Subnet Mask is 255.255.255.* or 255.255.255.0
  •    Total No. of nodes can be connected = > (0 to 255) = 256
  •    IPv4 Netid Range Varies: 192-223
                Eg.  192.168.1.0/24 – Starting and Ending IP Range 
  • Mask is over only 1st 24 bits
  • That means only first 8 bits (Netid) are fixed (varies from 192-223) next 16 bits can be varying from (1-255)
  • These 24-Bits (3 Bytes Netid) are defined by IANA (Internet Assigned Number Authority) for small organizations with a small number of hosts attached
  • Rest 8-Bits (Hostid) can vary from (0-255)
  • It implies that with single Netid there can be only (256) nodes attached

IP Addressing Part 1 IP Addressing Part 2

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