As described in [1] the IP (Internet protocol) specifies the technical format of packets and the addressing field for all devices connected through a communication network, in this case Internet. IPv6 (Internet protocol version 6) is the most recent version of the IP, the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet.

In order to connect any device to Internet it’s necessary to provide an IP address to the device. The first version of an Internet Protocol publicly used was IPv4 (Internet protocol version 4). This protocol was created by the Defense Advanced Research Projects Agency (DARPA). IPv4 included an addressing system that used numerical identifiers consisting of 32 bits. The use of addresses with a length of 32 bits limits the total number of possible addresses to a number of approximately 4.3 billion addresses for devices connected to internet around the world. The expected number of devices connected to Internet by means of IoT applications will be soon bigger than the number of addresses provided by IPv4. For this reason, the agency responsible for standardization of Internet protocols: The IETF (Internet Engineering Task Force) has been working in a new IP version from 1998: The IPv6, the successor protocol that is intended to replace IPv4 was first formally described in Internet standard document RFC 2460 [3].

IPv6 uses a 128-bit address format, allowing 2¹²⁸, or approximately 3.4 10³⁸ addresses, approximately 8 10²⁸ times as many as IPv4. While increasing the pool of addresses is one of the most important benefits of IPv6, there are other important technological changes in IPv6 that will improve the IP protocol: easier administration, better multicast routing, a simpler header format and more efficient routing, built-in authentication and privacy support among others.

IPv6 addresses are represented as eight groups of four hexadecimal digits. These groups are separated by colons, but methods to abbreviate this full notation exist. The IPv6 header format is shown in Table 1.

The new features introduced with the IPv6 protocol are basically the following: A new header format, an efficient and hierarchical addressing and routing infrastructure, a much larger address space and stateless and both firewall address configuration, IP security, extensibility, a better Quality of Service (QoS) support and a new protocol for neighboring node interaction.

Moreover, the IPv6 protocol has solved some of the security problems found in IPv4 networks by adding the IPsec (IP security) as mandatory. As a result, IPv6 is more efficient. Security in IoT implementations must be a critical component of the device design and manufacturing processes to ensure that basic security requirements are in place.

IPv6 offers also improvements on mobility security: Any IPv6 node of the network can use a mobile IP both as required. Mobile IPv6 uses two extensions headline: A routing header for registration and a headline target to data delivery between mobile nodes and their corresponding fixed nodes.

Most IoT devices connect to the Internet using wireless communications. The communications speed and device mobility range must be ensured. Wireless communications standards cover various technologies, including Wi-Fi, Bluetooth, ZigBee, long term evolution standard (LTE), Narrowband IoT (NB-IoT) or the IoT-friendly versions of LTE: Cat-M1 and the enhanced machine type communications (eMTC).

On the other hand, indoor installations commonly use Wi-Fi and Bluetooth, while outdoor installations generally use LTE, NB-IoT, and Cat-M1. It must be taken into account that Wi-Fi power consumption is much higher than Bluetooth.