The current version of IP (IP version 4) has been extremely successful but according to experts, the Internet will face a serious problem in a few years. Due to its rapid growth and the limitations in its design, there will be a point when no more free addresses are available for connecting to new hosts. At that point, no more new web servers can be set up, no more users can sign up for accounts at ISP, and no more new machines can be set up to access the web or participate in online games. Many of us have heard of the proposals to convert the Internet Protocol standard from the current version IPv4 to a new standard IPv6. The reason for the new standard is the rapid growth of the Internet and IPv6 is being introduced to overcome the address space restrictions of the old one. IPv6 is a lot more than IPv4 by just adding and modifying some bits at the end to make the address space bigger. It is anticipated that there will be much more emphasis on real- time transactions. Many network administrators dislike changes like IPv6 because they fear some thing wrong can happen in future that will be for days or weeks later. But this is not going to be happen because, since an IPv6 network can talk to an IPv4 network and vice- versa.
The IPv6 header has a new format that is designed to keep in mind that it should out do the header overhead. This is done by changing the location of both non-essential fields and optional fields to extension headers that are placed after the IPv6 header. Currently only 32 bit address schemes are being used which is of IPv4 scheme.IPv6 has 128-bit (16-byte) source and destination IP addresses. The large address space of IPv6 designed for huge number of address allocation to fulfillment of the requirement of the internet.
[...] Figure 15 shows the Next Header field in the IPv6 header and zero or more extension headers that form a chain of pointers. Each pointer indicates the type of header that comes after the immediate header until the upper layer protocol is identified. Figure 15 Next header fields Extension Headers Order Extension headers are processed in the order in which they are present. Because the only extension header that is processed by every node on the path is the Hop-by-Hop Options header, it must be first. [...]
[...] The fragmentable part of the original IPv6 packet must only be processed at the final destination node. This part consists of the Authentication header, the Encapsulating Security Payload header, the Destination Options header for the final destination, and the upper layer PDU. Authentication Header The Authentication header provides data authentication (verification of the node that sent the packet), data integrity (verification that the data was not modified in transit), and anti-replay protection (assurance that captured packets cannot be retransmitted and accepted as valid data) for the IPv6 packet. [...]
[...] Also we can say that each host is listening for traffic on the following multicast addresses: The interface-local scope all-nodes multicast address (FF01::1) The link-local scope all-nodes multicast address (FF02::1) IPv6 Addresses for a Router An IPv6 router is assigned the following unicast addresses: A link-local address for each interface Unicast addresses for each interface (site-local address and one or multiple global unicast addresses) A Subnet-Router anycast address The loopback address for the loopback interface Additionally, each router is listening for traffic on the following multicast addresses: The interface-local scope all-nodes multicast address (FF01::1) The interface-local scope all-routers multicast address (FF01::2) The link-local scope all-nodes multicast address (FF02::1) The link-local scope all-routers multicast address (FF02::2) The site-local scope all-routers multicast address (FF05::2) IPv6 Interface Identifiers The last 64 bits of an IPv6 address are the interface identifier. [...]
[...] IPv6 offers such a large address space that it is likely devices and appliances of the future will contain IPv6 network processors and be stamped with IP addresses that act as serial numbers. Think of the security possibilities. If all devices are stamped with an unchangeable IPv6 address, we could easily catch criminals that connect stolen property to the Internet. Mobile IP Mobile computing is one of the most talked about technologies. With the explosion of mobile devices that need always-online connectivity, it is imperative that protocols be developed that allow for IP connectivity regardless of the physical location of a device. [...]
[...] New Protocol for Neighboring Node Interaction The Neighbor Discovery protocol for IPv6 is a series of Internet Control Message Protocol for IPv6 (ICMPv6) messages, that manage the interaction of neighboring nodes (nodes on the same link). Extensibility IPv6 can easily be extended for new features by adding extension headers after the IPv6 header. That was in options field of the IPv4 header, which can be only 40 bytes of options. IPv6 Addressing The IPv6 address space IPv6 address syntax IPv6 prefixes Types of IPv6 addresses Unicast IPv6 addresses Multicast IPv6 addresses Anycast IPv6 addresses IPv6 addresses for a host IPv6 addresses for a router IPv6 interface identifiers The IPv6 Address Space Let's first we see the most common feature that is large address space. [...]
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