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3. IP address allocation Japanese Page

In this section, IP address allocation is explained. As this procedure may be updated, please get the newest document when you apply for it. Refer to JPNIC FAQ, Q1/A1 in section 14 for the way to get documents.

3.1 A guideline for IP address allocation

IP addresses are assigned to computers, that belong to networks based on TCP/IP protocol.

JPNIC allocates and maintains IP addresses of computers within Japan. The IP addresses are internationally guaranteed and this is done with the collaboration of Internet Network Information Center (InterNIC) and Asia Pacific Network Information Center (APNIC). It also handles, adjusts information that are necessary for IP address administration and provides information services to the network users.

The networks that are inside Japan, apply to JPNIC for IP address allocation. As a rule, application for IP address allocation can not be directly made to InterNIC. However, if the network is in more than one country, then it might become necessary to apply to APNIC, which is the NIC of the Asia Pacific region.

IP addresses are allocated to the organizations that administrate computer networks based on TCP/IP protocol. Here organization means a group with a person who is in charge of the group. Therefore, the definition of organization in case of JP domain name allocation may not be the same as it is for IP address allocation. If an organization is administrating computer networks that are inside Japan, application for IP address allocation can be made from anywhere.

3.2 Limitation of IP address

IP address is managed internationally and the resource is finite. Therefore, application for IP addresses that are not really essential should be restrained. Please return the IP addresses that are not in use to JPNIC.

3.3 IP address classes

IP addresses are represented as four decimal integers separated by decimal points, where each integer giwves the value of one octet of the IP address. Normally each IP address contains a network part and a host part. Depending on the left most octet, the address can be categorized in 5 classes and they are given below.

Type Value of left most octet
Class A 1 -- 127
Class B 128 -- 191
Class C 192 -- 223
Class D 224 -- 239
Class E 240 -- 255

The network parts of IP addresses that are in class A are of one octet. For example the IP address means that the network part is 1 and the host part is 2.3.4. Class A address can connect almost 17,000,000 (2 to the power 24 -2) machines.

The network parts of Class B addresses are of 2 octet. Around 6500 (2 to the power 16 - 2) machines can be connected to a Class B address.

The network parts of Class C addresses are of 3 octet. Two hundred and fifty four (2 to the power eight - 2) machines can be connected to a Class C address.

Class D and Class E addresses are used for special purposes (see RFC1166, you can get it via ftp.nic.ad.jp, please refer sec.13 ).

The applicants should consider about the future developments and apply for the required address Class. More than 70% of the Class B addresses has already been allocated as of April 94, and only a small number of addresses are left. It is strongly recommended, that instead of applying for a Class B address, the applicant should apply for a number of Class C addresses.

JPNIC administrates Class C addresses with the cooperation of InterNIC/APNIC and allocates network part. The applicant administrate the host part of the allocated IP address. In case of a Class B address, the application should be directed JPNIC. JPNIC screens the documents, and if it finds that the application is appropriate then it forwards the application to InterNIC via APNIC. The final decision is taken by IANA (Internet Assigned Numbers Authority).

3.4 Internet and IP network structure

Due to the rapid growth of the Internet, in order to maintain mutual connectivity with public Internet there are opinions that IP addresses should be unique. On the other hand, there are opinions that while allocating IP address, the route should be considered in order to manage it easily.

However, on the other hand, there is a growing demand for networks based on TCP/IP.

There exist a number of address allocation schemes based on these ideas. Globally unique addresses are not necessary for networks that are not externally connected and addresses are reserved for these kind of networks (see RFC1597, you can get it via ftp.nic.ad.jp, please refer sec.13). The steps are described in the above mentioned document. Although this address is not the subject of RIP on the Internet, it can be freely used without performing the registration to JPNIC.

In case of a globally unique address (global address), the application procedure is given below.

3.5 Application procedure

3.5.1 IP address allocation through provider

JPNIC allocates a part of IP addresses to the provider of the Internet connections. IP addresses can be availed through these providers.

IIJ, SPIN, InfoWeb, WIDE, IMnet and MESH project are in charge as of February 1995. If the applicant wants to connect to these projects, then the allocation will be from the address blocks for which the project is authorized. The requirements for obtaining a address from a provider is the same as it is with JPNIC.

If the applicant has already obtained address from JPNIC but the routing information regarding that address is not announced then the applicant can obtain class C address from a provider. Not only that, address can be obtained from a provider on the condition that the present address is going to be returned.

Although, it is not necessary to return the allocated address to the provider, in case the address is disconnected from the provider and another address is to be obtained from a different provider, then one of the following methods should be followed.

  1. Return the previous address and obtain another address from a different provider.
  2. A Class C address can be obtained from another provider on the condition that the previous address is not going to be announced to the Internet.

Even if the application is directed to JPNIC, if it is found that the applicant has a plan to connect to the above mentioned projects then the application will be redirected to the person who is in charge of that project.

3.5.2 Allocation from JPNIC

If the above mentioned 3.4 and 3.5.1 are not applicable and it becomes necessary to apply to JPNIC, then the applicant should follow the directions given in the enclosed application form (see sec.14, Q1/A1), and the administrative contact should take the responsibility to fill out the same.

The allocation is based on RFC1466. Hence, as a rule, the number of expected hosts for the next two years is divided by 256 and the number of allocation to be made is the round up number of the division result. However, this kind of allocation may cause harm to the network architecture. In that case the minimum number of required address can be obtained by mentioning a subnetwork in the application form.

In case of sending the application by post, please fill out the form by a word processor. Technical contact should correspond to JPNIC regarding the application, and after the IP address is allocated, they should administrate the same.

Application can be send either by e-mail or by post. In order to reduce the work-load of the JPNIC secretariat, the applicants are requested to send their application by e-mail. If the technical staff doesn't have access to e-mail, then someone who has access to e-mail can act as an intermediary for introducing the applicant. It should be noted, that JPNIC does not accept applications by fax.

As a rule, correspondence from JPNIC to technical contacts(in case of an intermediary, from now on the intermediary and the applicant will be referred as the applicant) can be done in the same way as explained above.

The e-mail address for application is apply@ip.nic.ad.jp. In case of using postal service, please write down " IP address allocation" on the envelope, enclose two self-addressed envelopes with postal stamp. The application should be directed to JPNIC secretariat IP address allocation group. The self-addressed envelopes will be used to inform the applicant about the acceptance of the application and the allocation of IP address.

JPNIC screens the application and informs the applicant about the approval/disapproval of the application within ten days.

If the application is approved, JPNIC sends a number to the applicant. The applicant should use the number for any enquiry regarding the application. In case of enquiring by e-mail, the number should be written on the subject field as given below.

Subject: question on XXX XXX XXX (IP-940601)

If the number of addresses requested do not exceed the criterion fixed by JPNIC, then the IP addresses will be allocated within ten days from the acceptance of the application and the applicant will be informed about it. However, if there is a delay for allocating address blocks to JPNIC from InterNIC/APNIC then there may be a delay in allocating the addresses. In that case JPNIC will inform the applicant about the status within ten days.

In case of application via postal service, application for Class B addresses and application where JPNIC can not make the allocation, the above does not apply.

If the application cross the limit, then JPNIC decides whether to allocate the addresses that have crossed the limit through discussions.

Excluding the information related to number of hosts, number of subnetworks, connection to Internet; JPNIC and InterNIC will treat all the other information filled out by the applicant as a public information. However, other applicants can not avail these information without the permission of the original applicant. The present or estimated number of hosts and subnetworks filled by the applicant in the application form should be appropriate. JPNIC may cancel the allocation if it is found that there are wrong information in the application.

If an organization has already received addresses and wants to apply for more addresses, then the previously allocated addresses should be written in the application form. In this case, the previously allocated addresses will be neglected and based on the allocation criterion, the number of previously allocated address will be subtracted from the number of allocable addresses and the remaining number of addresses will be allocated. Based on the allocation criterion, serial addresses can be availed by returning the old addresses.

3.6 Change in the application, cancellation

If the applicant wants to change something in the application form or in case of a cancellation, the applicant is requested to contact JPNIC immediately. The procedure for changing, cancelling application before the allocation of IP addresses is the same as that of the application procedure. However, the number given by JPNIC to the applicant should be written in the application.

3.7 Enquiries

Enquiries related to IP address allocation and administration can be send to JPNIC via e-mail (query@ip.nic.ad.jp), post or by fax (03-5684-7256).

For enquiries that are related to application, please write down the number given by JPNIC. FAX should be directed to the IP address allocation group of JPNIC.

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