Rules for assigning IPv6 addresses 1

Ruri Hiromi
General Manager, Advanced Solution Division, Intec NetCore, Inc



When connecting corporate network to IPv6, you will obviously need to obtain IP addresses. Address assignment procedures are different between IPv6 and IPv4. This article explains how IPv6 addresses are assigned, in comparison with IPv4 address assignment.


Preparing for the address request

(1) Difference between IPv4 address and IPv6 address

Specifications for IPv4 address and IPv6 address differs in terms of address length (32bit vs 128bit), address format, address type (unicast, anycast and multicast), and address scope (site-local, link-local, and global). Understanding the basics, such as specifications of basic header and extension header (placed one after another), and fundamental functions (plug-and-play, and incorporation of encryption and authentication) will help you when you design topology and troubleshoot operational problems.

We recommend you to study the basic differences between the specification of the protocol for IPv4 and IPv6 in advance, since this will be beneficial for you not only in terms of requesting address, but also for managing those addresses inside the company.

There are many books and articles about IPv6 available today. We recommend you to buy one textbook as a reference, and check the latest information on the web frequently to update your knowledge in a timely manner.

(2) Addressing plan inside the company

When distributing the assigned IP address inside the company and controlling the path, you need to take into account the size of the network, conditions regarding network operations, monitoring methods, purpose of the network, and future scalability. If it’s not possible to predict the future role of the network at the time of deployment, it might still be useful to summarize various physical and logical factors regarding the network operation, and make a concise administrative policy so that you could flexibly adapt to various situations in the future. It is also a good idea to consider what type of connectivity you will be using and plan address management accordingly.

(3) Obtaining the latest information regarding registries

Registries that administer IP addresses are organized in a hierarchical manner.

IANA is at the top of this hierarchy, and it is responsible for all the numbers related to the Internet (not only IP address, but also other numbers such as service port number). IANA distributes IP addresses to regional registries called RIR.

There is a RIR for each of the following regions, North America (ARIN), Europe (RIPE•NCC), Asia Pacific (APNIC), Latin America (LACNIC), and Africa (AfriNIC). Each RIR administers IP address numbers within its region. RIR assigns IPv6 addresses to ISPs. The smallest assignment size is /32. In addition, RIR directly allocates IPv6 addresses to special services such as Internet Exchange (IX). In this case, the smallest unit of allocation is /48.

Registry’s address assignment procedures do not change in a brief period of time, since all changes must go through time consuming policy deciding process. However, allocation procedures for /48 has only recently been decided, and we recommend you to check the latest information using sites listed below.

IANA... http://www.iana.org/ipaddress/ip-addresses.htm
APNIC... http://www.apnic.net/services/ipv6_guide.html
JPNIC... http://www.nic.ad.jp/ja/ipv6/index.html


Administration of IPv6 address

As we mentioned before, the scope of administration is different between IPv4 and IPv6. In the case of IPv4, administrative work regarding IP address has been moved down from regional registry level to national registry level (in Japan’s case JPNIC). General users and ISPs needed to become a member of JPNIC, and JPNIC allocated or assigned addresses to them. More recently, JPNIC has stopped the direct assignment of addresses to general users. In the case of IPv6, this approach is further advanced, and RIR only performs assignment to ISPs or other organizations that provides user services.

In this system, end users acquire IPv6 addresses together with the Internet connection service. As for JPNIC, currently it is providing agent services for requests to APNIC, to its IPv4 IP address management agents and its members. If you are already a JPNIC’s IP address management agent or a member, you can use this service, and there is no need to become a member of APNIC.Below is a brief summary of operations of registries

(0) Address policy

To assign means to distribute address space to registries and ISPs, for the purpose of subsequent distribution by them. To allocate means to delegate address space to an ISP or end-user, for specific use within the Internet infrastructure they operate.

(1) Allocation related issues (subject is ISP)

Registry assigns addresses basically to ISPs that provides IPv6 communication services to users.

For IPv4 addresses, companies were allowed to receive allocations if they met certain requirements regarding the use of addresses. However, for IPv6 addresses, you are required to provide connectivity services in order to receive allocations. Basically, vast majority of companies will not be a subject of assignment, but will get address allocation from ISPs.

Procedure for allocating addresses which are used only in a limited network, such as IX, has been established recently. This is a new procedure and RIRs differ in their level of preparation for this. Therefore the procedures for this type of allocation might be confusing. However, since review process for requests by IX is relatively simple, we think it’s worthwhile to consider this approach. With this procedure, IX service providers will obtain /48 allocation directly from a RIR.

After the review of the request by RIR, /32 will be allocated.

The requirements for receiving allocations are,

• Expectation of more than 200 users within a year (200 of /48 connection)
  
• Establish multiple connections to the outside network.

To request the allocation, you become a member of APNIC, and directly apply to APNIC. It is also possible to become JPNIC’s IP address management agent, and use JPNIC’s agent service.

(2) Issues regarding allocation (for general users)

Allocations are made in connecting users to the ISP. Address space that gets assigned depends on the ISP and the service it provides (/48 or /64, for example. First-tier ISP might assign /40, /44 and other blocks to the secondary ISP.). Assignment fee depends on the ISP, but in general it starts from 1000 yen.

Address allocation is made for every contract of connection service. If you are using multiple ISPs, you will be receiving alllocation from multiple ISPs. Since the allocated IPv6 address space depends on the connection, you must change the address when you change the ISP.

Procedures for requesting IPv6 addresses are basically the same as those for obtaining IPv4 CIDR address blocks, and you just need to follow the instructions from the ISP.

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