The history of IPv6 begins with a real need we have today. When IPv4 was conceived, in the 1970s, the creators could not imagine the great success that it would have throughout the world. Due to the lack of addresses, the research team called Internet Engineering Task Force (IETF) began to look for a substitute for IPv4, which in principle was called Internet Protocol Next Generation (IPng), but finally took the name of IPv6.

The IPv4 protocol has a 32-bit address space, which means that to calculate the total number of possible addresses, we can do it by taking 2 raised to 32, making a total of 4, 294, 967, 296 addresses.

The IPv6 protocol has expanded the address space to 128 bits, making a total of 340, 282, 366, 920, 938, 463, 374, 607, 431, 768, 211, 456 addresses available.

The main characteristics of the IPv6 protocol are as follows:

• Greater address space
• Plug-and-play auto-configuration
• Security included in the protocol core (IPsec)
• Quality of Service (QoS) and Class of Service (CoS)
• Multicast, which sends a single package to a group of receivers
• Anycast, which sends a packet to a receiver within a group
• Efficient and extensible IP packets, there is no packet fragmentation in the routers, aligned to 64 bits (optimal processing with 64-bit processors), and with a fixed-length, simpler header, which allows faster processing by routers
• Possibility of packages with payload (data) of more than 65,535 bytes (jumbograms)
• More efficient routing in the backbone of the network, due to a hierarchy of addressing based on aggregation
• Compensation and multi-homing, which facilitates the change of service provider
• Mobility characteristics

It is necessary to say that many of these features are standards that are still in the implementation phase. IPv6 addressing is still in a phase of evolution and it will take several years for some functionalities to be completed.