IP Addressing:

i. IP is responsible for addressing and routing in the TCP/IP environment.

ii. An IP address is 32-bits in length, grouped into four 8-bit octets and each octet is represented by a decimal number from 0-255.

iii. Four decimal numbers are separated by periods in a format called dotted decimal notation.

Example: 172.24.208.192

Divided into two parts: network ID and host ID, In the above address, host ID 208.192 resides on network 172.24.

I) IP Address Classes :

IP Addresses are categorized in Classes A to E. Only IP addresses in the A, B, and C classes are available for host assignment.

• Class A:

  i. Value of the first octet is between 1 and 127.

  ii. Addresses beginning with 127 are reserved for loopback.

  iii. IP registry assigns the first octet, leaving the last three octets to be assigned to hosts.

  iv. Intended for large corporations and government.

• Class B :

  i. Value of the first octet is between 128 and 191.

  ii. IP registry assigns the first two octets, leaving the third and fourth octets to be assigned to hosts.

  iii. Intended for use in medium to large networks.

• Class C :

  i. Value of the first octet is between 192 and 223.

  ii. IP address registry assigns the first three octets.

  iii. These networks are limited to 254 hosts per network.

  iv. Intended for small networks.

• Class D:

  i. Value of the first octet is between 224 and 239.

  ii. Reserved for multicasting.

• Class E :

  i. Value of the first octet is between 240 and 255.

  ii. Reserved for experimental use and can’t be used for address assignment.

II) Private IP Addresses:

Due to the popularity of TCP/IP and the Internet, we are running out of unique IP addresses, A series of addresses have been reserved for private networks (networks whose hosts can’t be accessed directly through the Internet.)

• Reserved addresses:

  i. Class A addresses beginning with 10.

  ii. Class B addresses from 172.16 to 172.31.

  iii. Class C addresses from 192.168.0 to 192.168.255.

  The addresses in those ranges can’t be routed across the Internet.

III) Internet Protocol Version 6 :

IPv6 solves some problems in IPv4:

i. Limits of the 32-bit address space

ii. Lack of built-in security

iii. Complicated setup

iv. Lack of built-in quality of service (QoS)

v. Better routing and better improvement for multicasting.

IV) IPv6 :

i. An IPv6 address is 128 bits instead of 32 bits in IPv4 IP Security (IPSec) protocol is incorporated into IPv6. IPv6 is autoconfiguring (no IP address to assign and no subnet mask to determine Microsoft Internet Protocol Version 6 (IPv6)

ii. IPv6 Addresses Specified in hexadecimal format, 8 blocks of 4 hex values.

iii. 16-bit sections separated by a colon

iv. Examples –FE80:0000:0000:D1AC:F0CD:00B9:0000:B00D

–2001:1B20:0302:442A:1100:2FEA:00A4:002B

v. You can remove leading zeros

–FE80:0:0:D1AC:F0CD:B9:0:B00D

–2001:1B20:302:442A:1100:2FEA:A4:2B

vi. Consecutive block of zeros can be replaced by ::

– FE80::D1AC:F0CD:B9:0:B00D