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In this article:
- Introduction to IPv6
- Features of IPv6
- IPv6 addressing conventions
Introduction to IPv6
IPv6 stands for Internet Protocol version 6 which is an IP standard at the network layer. It is made use of to exhange data over a packet-swtiched network by electronic devices connected to the network. The IPv6 standard is the successor to the IPv4 standard as an Internet Protocol for general use.
The IPv6 standard was laid down by Steve Deering and Craig Mudge at Xerox PARC. In 1994, it was accepted by the Internet Engineering Task Force. At that time, it was known as "IP Next Generation" or IPng. IPv5, developed before this, was more of an experimental streaming protocol for video and audio communication over a network and not a successor to IPv4.
The basic advantage that IPv6 has is that it allows for around 3.4X1038 internet addresses which are sufficient for providing a unique address to eacg cell phone and other electronic devices. This was a also a major reason for creating this protocol since the IPv4 standard was already showing signs of address exhaustion.
Inpsite of its advantages, IPv6 standard does not find widespreads usage. Its use is very limited and low as comapred to that of IPv4 on the internet. It is predicted that both, the IPv4 and IPv6 standards, will be supported side by side for some years to come.
Features of IPv6
IPv6 is more of an extension to the IPv4 standard, rather than being a complete reconstruction. Most of the protocols at the transport and application layer remain the same or require very minor changes. The following are some key features of the IPv6 standard:
- Larger address space
IPv6 provides a larger address space as compared to the IPv4 standard by using addresses that are 128 bits in size. This is the main characterisitics of the standard.
The advantage that this has is that more addresses are possible in the network and the danger of exhaustion of the address space provided by IPv4 is evaded. This also eliminates the use of NAT and other devices that change the end-to-end nature of internet traffic.
Another advantage that this larger space has is that it is more difficult to scan such IP blocks for vulnerabilities which IPv4 was an easy prey for. This means even more network security from mailicious traffic.
The 128-bit long address space also allows for easier administration of the network and helps prevent fragmentation of the address space which may lead to smaller routing tables hence decreasing the efficiency of the network. The IPv6 standard has ensured consistency with 64 bit processors by making the address space 128-bit long which would be easy to manipulate using such processors. However, a major disadvantage here is that the usage of bandwidth is not efficient in the IPv6 standard.
- Stateless autoconfiguration of hosts
Under IPv6, hosts can be configured automatically irrespective of their state by using a multicast (broadcast) when they connect to the network for the first time. This way, configuration parameters are passed to it and routers can then send the network-layer configuration parameters.
- Jumbograms
IPv4 limits the packet size to 64KiB of a payload. This limit is lifeted by the IPv6 standard (if the communicating nodes are capable of it). This done by using packets that have a larger size than this called Jumbograms.
- Faster routing
The header structure of the IPv6 standard supposedly improves performances of the routing facilities.
- Network-layer security
For ensuring network-layer security, the IPv6 standard features the Ipsec protocol which is meant for IP network-layer encryption and authentication. This protocol forms an integral part of the standard.
IPv6 addressing conventions
The two main rules or conventions are followed for assigning addresses under the IPv6 standard:
- 128-bit length
Each network address is 128 bits long and has two parts to them. The first part is a 64-bit network prefix while the second is a 64-bit host part which mayve generated automatically or assigned one after another.
- Notation
IPv6 addresses are written as eight groups with each group containing four hexadecimal digits, seperated by a colon (:) sign. A group containing only zeros is omitted and a double colon is put in its place (::).
It is notable that there are no special address ranges for broadcasting under IPv6. For implementing this, a multicast to all-hosts maybe used.
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