‫IPv6 was developed by the Internet Engineering Task Force IETF, I'm sure you looked it up to deal with
‫the long anticipated problem of IPv4 address exhaustion.
‫So IPV six is intended to replace IPv4.
‫IPV six became a draft standard in December 1998 and became an internet standard on the 14th of July
‫2017.
‫So instead of 32 bit addressing of IPv4, which provides approximately four point three billion addresses,
‫IPv6 uses a 128 bit address.
‫So that theoretically gives us to do the power of 128 or approximately 3.4 times 10 to the 38th addresses.
‫Big Number.
‫You can check my math later, but stick with me for now.
‫I mean, the actual number is slightly smaller, is multiple ranges are reserved for special use or
‫they're just completely excluded from use.
‫But with a rough calculation, the total number of possible IPv6 addresses is more than seven point
‫nine times 10 to the power of 28 times as many as IPv4.
‫The two protocols, IPv4 and IPv6 are not designed to be interoperable.
‫Complicating the transition to IPv6, however, several IPv6 transition mechanisms have been devised
‫to permit communication between IPv4 and IPv6 hosts.
‫In addition to offering more addresses, IPv6 also implements features not present in IPv4.
‫Simplified header.
‫IPV six, his header has been simplified by moving all unnecessary information and options, which are
‫present in the IPv4 header to the end of the IPv6 header.
‫The IPv6 header is only twice as big as an IPv4 header because that IPv6 address is four times longer.
‫End to end connectivity.
‫Every system now has a unique IP address and can traverse through the internet without using NAT or
‫other translating components.
‫After IPv6 is fully implemented, every host can directly reach other hosts on the internet with well
‫with some limitations involved, like a firewall organization, policies and stuff like that.
‫Auto configuration.
‫IPv6 supports both stateful and state stateless auto configuration mode of its host devices.
‫This way, the absence of a DHCP server does not put a halt on Inter segment communication.
‫Faster forwarding and routing.
‫A simplified header put all unnecessary information at the end of the header like we saw earlier, the
‫information contained in the first part of the header is adequate for a router to make its routing decisions,
‫thus making them as quickly as looking at the mandatory header.
‫IP SEC.
‫Initially, it was decided that IPv6 must have IP SEC making it more secure than IPv4.
‫This feature has now been made optional.
‫IP SEC Internet Protocol Security is a framework of open standards for helping to ensure private, secure
‫communications over internet protocol networks, IP networks through the use of cryptographic security
‫services.
‫IP SEC is an end to end security scheme operating in the network layer, while some other internet security
‫systems in widespread use TLC and S.H. operate in the upper layers.
‫IP can automatically secure applications at the IP layer.
‫No broadcast.
‫Though Ethernet and Token Ring are considered a broadcast network because they support broadcasting,
‫IPv6 does not have broadcast support anymore.
‫It uses Multicast to communicate with multiple hosts.
‫Mobility IPv6 was designed keeping mobility in mind.
‫This feature enables hosts such as a mobile phone to roam around in different geographical areas and
‫remain connected with the same IP address.
‫The mobility feature of IPv6 takes advantage of auto IP configuration and extension headers.
‫Extensibility.
‫One of the major advantages of the IPv6 header is that it is extensible, adding more information and
‫the option part.
‫IPv4 provides only 40 bytes for options, whereas options and IPv6 can be as much as the size of the
‫IPv6 packet itself.
‫What is the IPv6 packet you ask?
‫You came to the right place.
‫And IPv6 packet is the smallest message entity exchanged via the internet protocol across an IPv6 network.
‫But stay with me here.
‫The packets consist of control information for addressing and routing and a payload consisting of user
‫data.
‫The control information in IPV six packets is subdivided.
‫You know, mandatory fixed header and optional extension headers.
‫The fixed header starts an IPv6 packet and as a size of 40 octet, which means 320 bits.
‫Its format is shown in the slide.
‫Version is constant six, payload length is the size of the payload in bytes, including any extension
‫headers, hop limit replaces the time to live field in the IPv4.
‫Well, I think source address and destination address fields are fairly obvious.
‫Extension headers carry optional internet layer information and are placed between the fixed header
‫and the upper layer protocol header.
‫128 bit IPv6 addresses are written using Hexadecimal as opposed to dotted decimal back in IPv4.
‫Because a hexadecimal number uses four bit, this means that an IPv6 address consists of 32 hexadecimal
‫numbers.
‫These numbers are grouped in fours giving eight groups or blocks.
‫The groups are written with a colon as a separator.
‫And IPv6 address example is shown in this line.
‫So because of the length of the IPv6 addresses, various shortening techniques are employed, the main
‫technique being to omit repetitive zeros, as shown in the example.
‫So as I mentioned before, in IPv4, an address is split into two components, right?
‫Networking ID and a host I.D..
‫This was done initially using address classes and then later using subnet masking.
‫In the unit cast addressing of IPv6, it's done in the same way.
‫The first step is to split the address into two parts.
‫Addresses split into two 64 bit segments.
‫The top 64 bits is a network I.D. and the lower 64 bit is the host I.D..
‫The most significant 64 bits are used for routing and the least significant 64 bits identify the address
‫of the interface or host.
‫This block is derived from the actual physical or Mac address in practice.
‫So if we look at the most significant 64 bits in more detail, we can see that it's split into two blocks
‫of 48 and 16 bits.
‫Now, the least significant 16 bits are used for subnets on internal networks and are controlled by
‫a network administrator.
‫The most significant 48 beds are used for the global network addresses and are used for routing over
‫the internet.