Internet Protocol Version 6

IPv6 is a next generation layer 3 protocols that transfers data securely through Internet.

Currently the IP protocol version4 is used. However it has some limitations.

  1. Maximum number of address available – 4.3 billion (approx.), but Class D and Class E are not used to assign to computers.
  2. There is no inbuilt security in ipv4.

Till now the first limitation of using PRIVATE address, CIDR and NAT/PAT has not been solved. As the network of India, China and some others countries are growing fast so this IPV4 address range is now about to end. Additionally NAT/PAT also creates some problem like end to end security or complex network design, so there is a need to move to another new network protocol and addressing scheme   IPV4 -> IPV6.

A simple comparison between IPV4 and IPV6 is as below:

                   IPV4                IPV6
  1. 32 bit address
  2. Decimal format
  3. Total no. of address -232  
  4. Broadcast support
  5. Support Classfull/Classless Addressing

6.      ARP


  1. 128 bit address
  2. Hexadecimal format
  3. Total no. of address – 2128
  4. No Broadcast support. Use Multicast instead
  5. Support Only Classless
  6. No ARP, NDP(Network Discovery Protocol)


IPv6 address space:

IPV4:         232 =4,294,967,296 (4.3 billion approx.)

IPV6:     2128 =340,282,366,920,938,463,463,374,607,431,768,211,465


Thus one can get 79 trillion times more addresses than total number of IPV4 addresses

2128 =232 * 296 (79 trillion trillion)    


Ipv6 address:

2030:A1B2:25C9: AAAA: 1234: DBCA: 21B4:555C

IPV6 support abbreviations-

IPv6 address “2010:0000:0000:0000:0000:0000:0000:140B” can be shorten to-

=> 2010::140B

But if there is any digit or number between continuous “0″   like



2010::130F:: 140B   is incorrect , because more than one double colon (::) in one address cannot be used.

Correct is

2010:0:0:130F:: 140B

At least  one should write one “0” for each quartet (4 hex digit).


IPv6 Unicast address is of 3 types

Global Unicast: It works like original IPv4 Public address.

Link-Local Unicast: Every IPv6 host interface (and router interface) can create their own link-local address automatically. It can work only in local Subnet.

Unique-local Unicast: Works somewhat like private IPv4 addresses.

Address Format:

At first there were thought of having two distinct components.

  • 64-bit field designated as the network portion.
  • 64-bit field designated as the host portion

   IPv4-IPv6 Co-existence/Transition

  1. Dual-stack techniques- Allows IPv4 and IPv6 to co-exist in the same devices and networks.
  2. Tunnelling techniques- Tunneling is an integration method in which an IPv6 packet is encapsulated within another protocol, like IPv4.
  3. Translation techniques- Allows IPv6-only devices to communicate with IPv4-only devices.

Problems with ipv6 Implementation

  1. Complex Addressing.
  2. Administrators and Network Engineers are not trained.
  3. Older devices do not support ipv6 properly.
  4. Tough to change whole internet addressing scheme all at once.


So there is a need to increase the use of IPv6 address parallel to IPv4. Then IPv4 will be dropped and IPv6 will take command of the whole Network.


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