Application of IPv6 technology in IOT (1)

Internet of things (IOT) is also known as sensor networks and ubiquitous networks. In layman's terms, Iot is the "Internet of things connected to things ". A large network formed by the combination of various information sensing devices through the Internet. This includes two meanings: first, the Internet of Things is an extension and extension of the internet, and its core and foundation are still the Internet. Second, its user end is not only an individual, but also any item, terminals may be complex and support a large number of functions. it may also be very simple. it has a single function and cannot load many complex processing algorithms. The concept of Iot covers a wide range of technologies from terminals to networks, from data collection and processing to intelligent control, from applications to services, and from people to things. In the long run, the Internet of Things is expected to become an emerging industry that is larger than the current Internet industry. Relevant international institutions predict that its scale will exceed 30 times of the existing Internet scale in the future.

Network dilemmas of Iot

The rich applications of IOT and the large node scale bring both great commercial potential and technical challenges. First, Iot is composed of a large number of node connections. no matter whether they are self-organized or connected through an existing public network, the communication between these nodes will inevitably involve addressing issues. Currently, the addressing system of Iot can adopt two methods. one method is to address E.164 telephone numbers. However, most of the network communication protocols of Iot applications currently use the TCP/IP protocol, the telephone number editing method must convert the telephone number and IP address. This increases the technical implementation difficulty and increases the cost. At the same time, the address space of the E.164 addressing system is small. And cannot meet the address requirements of a large number of nodes. The other method is to directly use the IPv4 address addressing system to address Iot nodes. With the rapid development of the Internet itself. IPv4 addresses are becoming increasingly scarce. According to the current address consumption speed. The IPv4 address space is difficult to meet the network address needs of the Internet of Things. On the other hand, Iot needs massive addresses. the address allocation method is also required. the allocation of massive addresses cannot be manually allocated. The traditional DHCP allocation method also puts forward extremely high performance and reliability requirements for DHCP servers in the network, which may cause insufficient performance of DHCP servers, it becomes a bottleneck for network applications. Second, the current lack of mobility on the Internet has also led to the bottleneck of Iot mobile capabilities. The IPv4 protocol did not fully consider the routing problem caused by node mobility at the beginning of the design, that is, when a node leaves its original network, how can we ensure the accessibility of the node. Due to the aggregation of IP network routes, route entries in the network routers are aggregated by subnet. when a node leaves the original network, its original IP address leaves the subnet, And the node moves to the destination subnet, the routing information of this node does not exist in the routing table of the network router device (in order not to disrupt the aggregation of the entire network, or to allow the route of a mobile node in the destination subnet ), the external node cannot find the moving node. Therefore, how to support the mobility of nodes must be implemented through special mechanisms. In IPv4, IETF proposes the MIPv4 (Mobile IP) mechanism to support the movement of nodes. However, this mechanism introduces the famous triangular routing problem. For the movement of a small number of nodes, the network resource loss caused by this problem is small. for the movement of a large number of nodes, especially the movement of unique node groups and layer movement in IOT. this can quickly exhaust network resources and paralyze the network.

Thirdly, network quality assurance is also a problem that must be solved during the development of Iot. Currently, there are two QoS Technologies in IPv4 networks. One is to reserve resources (interserv) and the other is to reserve certain network resources for data streams Using RsVP and other protocols. the packet transmission quality is ensured during data packet transmission. The Diffserv technology is used, and the IP packet carries the priority mark. the network device determines the packet forwarding priority policy based on these priority tags. At present, the quality of service in IPv4 networks is basically based on the stream type. diffserv is used to ensure end-to-end service quality. For example, if the video service requires low packet loss, latency, and jitter, a high level of service is assigned to it: data Services are not sensitive to packet loss, latency, and jitter. Therefore, a low service quality level is assigned. Such a allocation method only takes into account the network-side quality requirements of services. the quality requirements on the application side of the business are not taken into account. For example, a common video service may have lower service quality requirements than an Iot-based surgical application. Therefore, the service quality assurance in Iot must be combined with specific applications.

Finally, the security and reliability of Iot nodes also need to be reconsidered. Due to the limited cost constraints of Iot nodes, many of them are based on simple hardware. It is impossible to process complex application-layer encryption algorithms, and the reliability of a single node cannot be very high, its reliability is mainly ensured by multi-node redundancy. Therefore, the traditional application-layer encryption technology and network redundancy technology are difficult to meet the needs of Iot.