In 1991, the IETF decided that the current version of IP, called IPv4, had outlived its design. The new version of IP, called either IPng (Next Generation) or IPv6 (version 6), was the result of a long and tumultuous process which came to a head in 1994, when the IETF gave a clear direction for IPv6. IPv6 is designed to solve the problems of IPv4.It does so by creating a new version of the protocol which serves the function of IPv4, but without the same limitations of IPv4. IPv6 is not totally different from IPv4: what you have learned in IPv4 will be valuable when you deploy IPv6.The differences between IPv6 and IPv4 are in five major areas: addressing and routing, security, network address translation, administrative workload, and support for mobile devices. IPv6 also includes an important feature: a set of possible migration and transition plans from IPv4.Since 1994, over 30 IPv6 RFCs have been published. Changing IP means changing dozens of Internet protocols and conventions, ranging from how IP addresses are stored in DNS (domain name system) and applications, to how datagrams are sent and routed over Ethernet, PPP, Token Ring, FDDI, and every other medium, to how programmers call network functions.The IETF, though, is not so insane as to assume that everyone is going to change everything overnight. So there are also standards and protocols and procedures for the coexistence of IPv4 and IPv6: tunneling IPv6 in IPv4, tunneling IPv4 in IPv6, running IPv4 and IPv6 on the same system (dual stack) for an extended period of time, and mixing and matching the two protocols in a variety of environments.Internet Protocol Version 4 (IPV4)Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP) and it is the first version of the protocol to be widely deployed. Together with IPv6, it is at the core of standards-based internetworking methods of the Internet. IPv4 is still by far the most widely deployed Internet Layer protocol.IPv4 is described in IETF publication RFC 791, replacing an earlier definition RFC 760. IPv4 is a connectionless protocol for use on packet-switched Link Layer networks e.g., Ethernet. It operates on a best effort delivery model, in that it does not guarantee delivery, nor does it assure proper sequencing, or avoid duplicate delivery.IPV4 does not contain error control or flow control mechanisms.However it discards data if found corrupted through the checksum method employed in header of the datagram. These aspects, including data integrity, are addressed by an upper layer transport protocol e.g., Transmission Control Protocol. Ipv4 is the fourth version of Internet protocol, but the first one to be widely deployed.It uses a 32 bit addressing and allows for 4,294,967,296 unique addresses. Ipv4 has four different class types, the class types are A, B, C, and D.IPV4IPV6Source and destination addresses are 32 bits (4 bytes) in length.Source and destination addresses are 128 bits (16 bytes) in length.IPSec support is optional.IPSec support is required.IPv4 header does not identify packet flow for QoS handling by routers.IPv6 header contains Flow Label field, which identifies packet flow for QoS handling by router.Both routers and the sending host fragment packets.Only the sending host fragments packets; routers do not.Header includes a checksum.Header does not include a checksum.Header includes options.All optional data is moved to IPv6 extension headers.Address Resolution Protocol (ARP) uses broadcast ARP Request frames to resolve an IP address to a link-layer address.Multicast Neighbor Solicitation messages resolve IP addresses to link-layer addresses.Internet Group Management Protocol (IGMP) manages membership in local subnet groups.Multicast Listener Discovery (MLD) messages manage membership in local subnet groups.ICMP Router Discovery is used to determine the IPv4 address of the best default gateway, and it is optional.ICMPv6 Router Solicitation and Router Advertisement messages are used to determine the IP address of the best default gateway, and they are required.Broadcast addresses are used to send traffic to all nodes on a subnet.IPv6 uses a link-local scope all-nodes multicast address.Must be configured either manually or through DHCP.Does not require manual configuration or DHCP.Uses host address (A) resource records in Domain Name System (DNS) to map host names to IPv4 addresses.Uses host address (AAAA) resource records in DNS to map host names to IPv6 addresses.Uses pointer (PTR) resource records in the IN-ADDR.ARPA DNS domain to map IPv4 addresses to host names.Uses pointer (PTR) resource records in the IP6.ARPA DNS domain to map IPv6 addresses to host names.Must support a 576-byte packet size (possibly fragmented).Must support a 1280-byte packet size (without fragmentation).
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