It is time to plan IPv6 address resources.

IPv4 addresses are exhausted, and the IPv4 address resources in China are far from meeting the needs of users with high-speed growth. As a result, China will become one of the world's first countries affected by address shortage, this situation forces China's network operators to accelerate the deployment of IPv6 networks and services. In the initial phase of IPv6 deployment, it is critical to develop a scientific and reasonable network and business development plan. In combination with factors such as network layers, routing protocols, and traffic characteristics, the establishment of an IPv6 address resource deployment policy is a key part of the overall network planning, which will affect the basic network operation efficiency and Internet management effect.

Reduce network address fragmentation

The IPv6 address planning scheme affects the network-wide aggregation capability. In addition to carriers, other units with address requirements have mastered a considerable number of Address resources. when connected to the carrier's network, a large number of address fragments cannot be aggregated, this is the main cause of the rapid expansion of IPv4 route tables and the decline in route efficiency. In addition, traffic engineering, address portability, and so on make the problem more serious. In the IPv4 address allocation mode, the IPv6 massive address space puts forward higher requirements for improving the Routing aggregation capability. Otherwise, a large number of potential address fragments will inevitably lead to a rapid growth of Route tables. Therefore, the primary task of IPv6 address planning is to reduce network address fragmentation, enhance Routing aggregation, reduce CPU and memory consumption of routers and other devices, and improve network routing efficiency.

IPv6 address planning restricts address utilization, which affects the IPv6 address lifecycle. From 32-bit to 128-bit, IPv6 greatly expands the address space, but it is not infinitely available. IPv6 often ensures the uniqueness of Address Configuration by wasting address resources, IPv6 address stateless automatic configuration causes low IPv6 address utilization, for example, the IPv6 address of a mobile communication network is allocated with an address prefix in units of "/64" for each PDP context, and the home network is allocated with a prefix in units of "/48. Therefore, although IPv6 addresses provide a large amount of space, disordered development will lead to a serious waste of IPv6 addresses. It is imperative that you plan the IPv6 addresses in the early stage to save address space and prolong the IPv6 address lifecycle as much as possible, avoid the same pattern of premature exhaustion of IPv4 address space.

The IPv6 Address Allocation Scheme affects the effective management of addresses. Currently, China lacks effective management methods for allocated IP addresses. By scientifically planning the IPv6 address scheme, we can improve our country's network tracing capability when the Internet is attacked, and ensure network security and credibility.

Extended address Semantics

Generally, an IPv6 address consists of three parts: Global route prefix, subnet flag, and 64-bit interface flag. For prefixes allocated by international Address Allocation agencies, the remaining address bit prefixes must be prefixed before 65th bits.) The planning agencies and Internet operators can define their own prefixes and define relevant meanings. At the same time, the 64-bit interface identifier does not yet form a globally specific allocation rule. You can use the interface identifier to carry multiple types of information during planning. According to the current research results, IPv6 addresses can carry the following types of information.

Address Allocation is compatible with the hierarchical network topology. Assign the same network prefix to subnets in the same geographic range so that the 64-bit IPv6 address prefix reflects the geographical location information. Assigning IPv6 addresses based on the hierarchy of backbone networks, provincial networks, and man helps reduce the route table size, enhance system stability, and achieve Shortest Path addressing.

Address allocation reflects customer information and business type features. The user identity information is carried by the user in different access modes. If necessary, the user identity can be queried. Based on the business types of users on the Internet, the edge devices of the Internet complete subnet division, business sign registration, and policy settings, and configure the corresponding IPv6 address according to the business types of the end users. This scheme is easy to implement QoS Assurance and user traceability mechanisms. The disadvantage is that the service type division is difficult to unify and the existing protocols need to be upgraded.

Verify the source address based on the IPv6 address. The hash algorithm is used to generate verification information for the source IPv6 address and add it to the corresponding source address verification options, so that the relevant management nodes can check the authenticity of the source address, this solution is conducive to address spoofing, identity counterfeiting, denial of service attacks, and other security issues caused by counterfeit source IPv6 addresses. However, it needs to occupy a large segment of address space while implementing complicated mechanisms.

Improve address Utilization

In essence, the domestic plan for IPv6 unicast addresses is to allocate second bits in 128 bits except the prefix. Currently, international address distribution agencies do not provide clear rules for IPv6 Address Allocation. Address distribution agencies can follow some clear allocation principles and implement personalized allocation schemes based on actual conditions.

Avoid the negative impact of IPv6 address semantic overload. We recommend that IPv6 addresses only carry the following two types of information: first, considering that the biggest problem in the IPv4 addressing system is the expansion of routes, this problem may become more prominent in the IPv6 era, therefore, the IPv6 address prefix should reflect the location information and allocate continuous address space to each region as much as possible to improve the Routing aggregation capability and reduce the pressure on the router. Second, in order to enhance China's Internet management capabilities with IP addresses as the starting point, we can consider adding user identity signs, terminal device addresses and other information to IPv6 addresses.

Address planning should fully consider business growth needs. During Address Allocation, sufficient address space should be reserved for the future to better achieve Address Aggregation. For more information, see the IPv6 Address Allocation experience in Brazil. We recommend that you allocate addresses at a 100% or 300% retention rate. At the same time, to distinguish between users with high address requirements and general users, open up different address pools for them, that is, to reserve addresses with different address prefixes Based on the retention rate.

To reserve resources, you can compare and select Address allocation algorithms based on actual conditions, such as sequence and sparse allocation. The Sequence Algorithm is intuitive and simple, but it is difficult to accommodate multiple consecutive application address demands and burst bulk address applications, and cannot be adjusted based on the actual network size. The sparse matrix allocation method has a good aggregation, the disadvantage is that the space is evenly allocated to users, which has poor adaptability to applications of users of different scales. Unnecessary address conflicts and address space segmentation may occur.

Address utilization should be improved as much as possible to meet business and network development needs. China's Address Allocation management institutions conduct periodic evaluations on the changes in IPv6 address consumption speed of each unit, and release the address segments reserved by users with few address requirements in a timely manner. If you want to apply for a larger space, you need to analyze the future address requirements.

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