Ipv4 vs. Ipv6

Posted by szakwani on Nov 6, 2008 in English, Technology | 2 comments

Although the Internet Protocol version 4 (Ipv4) is the fourth revision in the development of the Internet Protocol, it was the only one which was deployed successfully to be used. The IPv4 is at the foundation of standards-based inter-networking methods of the Internet, and is still by far the most widely deployed Internet Layer protocol. Most the currently used internet communication uses IPv4. It is almost 20 years old.

IPv4 addresses are written in dot-decimal notation, which consists of the four octets of the address expressed in decimal and separated by periods. Example of an IPv4 address 192.0.2.10. The IPv4 uses a 32 bit addressing that is 4 octects 8+8+8+8 = 32 and 2^32 (4,294,967,296 unique addresses) .

Ipv4 has four different class types, the class types are A, B, C, and D. The ipv4 uses a subnet mask due to the larger growing number of computers. The subnet mask could also represent a way in understanding the network address and the number of hosts that can be allowed in the network minus two for the network address and the broadcast address.

IPv4 Header

Ipv6 is the next Internet Protocol, an advancement to the currently existing Ipv4. Pv6 is short for “Internet Protocol Version 6″. IPv6 is the “next generation” protocol designed by the IETF to replace the current version Internet Protocol, IP Version 4 (“IPv4″).

IPv6 has a large number of rooms available for the internet users. Compared to the Ipv4 which allows for only 4,294,967,296 unique addresses, the Ipv6 that uses a 128-bit system will hold 340-undecillion (thats 340 with 11 more zeros) this number is so vast that when one is born and starts counting continuously, he/she would need approximately 1105389096962130669995 millenniums to reach that number(or lets just say the number is really huge).

An example of Ipv6 is:
212. 121. 231. 235. 207. 242. 131. 235. 207. 127. 131. 235. 200. 142. 131. 215.

IPv6 is expected to gradually replace IPv4, with the two coexisting for a number of years during a transition period.

IPv6 Header

• Version – version 6 (4-bit IP version).
• Traffic class – packet priority (8-bits). Priority values subdivide into ranges: traffic where the source provides congestion control and non-congestion control traffic.
• Flow label – QoS management (20 bits). Originally created for giving real-time applications special service, but currently unused.
• Payload length – payload length in bytes (16 bits). When cleared to zero, the option is a “Jumbo payload” (hop-by-hop).
• Next header – Specifies the next encapsulated protocol. The values are compatible with those specified for the IPv4 protocol field (8 bits).
• Hop limit – replaces the time to live field of IPv4 (8 bits) routing hop count.
• Source and destination addresses – 128 bits each.

Why use IPv6?

1. Larger Address Space: address filed in IPv6 are 16 bytes long while the address filed of IPv4 is only 4 bytes in length. Due to the current development of hand gadgets and “everything connected” there is a need for a large number of unique addresses which in a while IPv4 will not be able to withhold.
2. Better header format: IPv6 header is lighter. the header is designed to speed up the routing process. In header of IPv6 options are separated from the base header. Options are inserted into base header only when required by the upper-layer data.
3. Provision for extension: IPv6 has been designed in a way that a protocol can be extended easily to meet the requirements of emerging technologies or new applications.
4. Resource Allocation support in IPv6: IPv6 provides a mechanism called Flow Label for resource allocation. Flow label enables source to send request for the special handling of a packet. This mechanism is really helpful in real-time audio and video transmission.

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