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Appendix A: Address Assignment

Registries

Provider-based Assignments

Cost of an IP Address

How to Find an IPv4 Address Delegation

How to Find an IPv6 Address Delegation

Internet Governance

Summary

 

 

Each host connected to an IP network must have an IP address. For connectivity on the Internet, the address space must be managed to ensure the uniqueness of each address.

 

In the past, Jon Postel was giving IP addresses to universities connected to the Internet (well, the Arpanet at that time). Then, Internic, an umbrella created by the US government, gave IP addresses to any requesting organization. At that time, Jon Postel was still managing the whole address space, giving ranges of addresses to Internic. 

 

Registries

Now, the Internet Assigned Numbers Authority (IANA) is managing the whole IPv4 address space and the IPv6 address space. IANA gives ranges of addresses to regional registries; those registries give addresses ranges to Internet Service Providers (ISPs) who then give addresses to corporations (or to smaller ISPs). Each level of delegation has to prove to the upper level that it has consumed most of its address space before requesting another range of addresses.

 

The three regional registries are:

·          American Registry for Internet Numbers (ARIN): http://www.arin.net

·          Réseaux IP Européens-Network Coordination Center (RIPE-NCC): http://www.ripe.net

·          Asia-Pacific Network Information Center (APNIC): http://www.apnic.net

 

ARIN covers North America, South America, the Caribbean, and sub-Saharan Africa. RIPE-NCC covers Europe, the Middle East, and parts of Africa. APNIC covers Asia and the Pacific.

 

If you are not connected to the Internet and don’t want to be, then there is an IP address space reserved for that situation. It is called the private address space and is described in RFC 1918 and discussed in the NAT chapter in this book.

 

            On the other hand, if you need addresses for your network, you should ask your upstream Internet provider to give you a range of addresses for your own use. As soon as you move to another provider, you will need to remove the previous range of addresses and renumber to the new range of address.

 

For Managers Only

 

To get IP addresses for your network, ask your upstream provider. Note that when you change providers, you will have to change the IP addresses.

Provider-based Assignments

Around 1996, to minimize the routing table explosion, the technical community agreed to enforce Classless Inter-Domain Routing by asking corporations to get their range of IP addresses only from their upstream provider. By doing so, the number of entries in the global routing table will grow at a much lower rate than the number of networks connecting to it, because ISPs aggregate the addresses of their customers. But there are some exceptions to this rule, mainly when you are multihomed.

 

In IPv6, the addressing architecture is based on provider-based addresses, which means that IPv6 enforces this CIDR at the beginning. As discussed in the IPv6 chapter, IPv6 clearly will be more scalable by this optimized routing and by the address space it has. The drawback of renumbering when using provider-based addresses has been addressed in IPv6 by a specific protocol.

Cost of an IP Address

In theory, an IP address costs nothing. The registries are not-for-profit organizations. They charge a fee to their clients (ISPs) for the registration service, not for the IP address themselves. In some ways, ISPs will include this cost in the prices of their service to their clients, so the effective cost of IP addresses is hidden somewhere.

How to Find an IPv4 Address Delegation

Each regional registry maintains a database of its address assignments. ISPs are mandated to provide the information about their own assignments to customers. All this information is available by using a simple query protocol called whois. From the early days, whois has been available in Unix as a command, but has not been available in the other environments. Now, all registries have a Web interface to the whois database, which makes it accessible to users. The following URLs point to the Web whois interface for all registries:

·          ARIN: http://www.arin.net/whois/index.html

·          RIPE: http://www.ripe.net/db/whois.html

·          APNIC: http://www.apnic.net/apnic-bin/whois.pl

·          Network Solutions (Internic): http://www.networksolutions.com/cgi-bin/whois/whois

·          US Department of Defense: http://nic.mil/cgi-bin/whois

 

The whois database not only includes IP addresses, but other data like the maintainers of those IP addresses, the Autonomous System (AS) numbers, etc.

 

Here is an example: I want to know who is responsible for the 206.123.31.0 address space. I choose to go to the ARIN whois Web interface (http://www.arin.net/whois/index.html) and ask for the address in Figure 1.

Figure 1 ARIN whois web interface.

 

The answer given by the ARIN whois database is shown in Figure 2.

Figure 2 ARIN whois answer to 206.123.31.0.

 

The answer in Figure 2 says that the 206.123.X.X range has been given by ARIN to the Canadian Registry, and the Canadian registry gives the 206.123.31.0/24 range to Viagénie Inc. Then, I click on NET-VIAGENIE to know more about it, it will show the information in Figure 3.

Figure 3 ARIN whois answer to NET-VIAGENIE.

 

This answer tells me where Viagénie Inc. is located, who is responsible for it, and what DNS servers are answering for the inverse mapping of those addresses.

 

The whois databases are all defined with objects (like the NET-VIAGENIE object) that have a maintainer associated with it. In this example, the maintainer ID of the NET-VIAGENIE object is MB841-ARIN. This is the way to keep track of who is responsible for which object. It is the same with the domain names registries.

 

How to Find an IPv6 Address Delegation

To test IPv6, a test network called 6Bone was built in July 1996. It is still running and alive. Each site has a prefix (address range) delegated from a test prefix allocated by IANA: 3ffe::/16. A registry with a whois interface has been set up to handle the registrations, and is available through the 6Bone Web site: http://www.6bone.net.

The official IPv6 addresses are available from the previous registries (ARIN, RIPE, and APNIC) and these registries have the same Web interface for both the IPv6 and IPv4 addresses.

Internet Governance

For a few years, work has been done in the global community for Internet governance, which covers many domains and issues. The current orientation for IP addresses assignments is to move the IANA functions to the Internet Corporation of Assigned Names and Numbers (ICANN: http:://www.icann.org). But at the time of this writing, many discussions are still pending.

For Managers

The regulation of the Internet is a hot issue and it will not be easily resolved. But it will certainly have many consequences for the way the Internet is managed. You should follow the discussions and be up-to-date in this area. The place to begin is at the Internet Society (ISOC) Web site (http://www.isoc.org) or ICANN Web site (http://www.icann.org).

Summary

Address assignments are controlled at the higher level by IANA. It assigns ranges of addresses to regional registries as needed, and those registries assign ranges of addresses to ISPs, which then assign to them to corporations. This enables CIDR, which makes Internet routing efficient. This process is for both IPv4 and IPv6. You can see the assignments by looking at the whois databases at the various registries.

 

Important discussions are currently being held on Internet governance, mostly around ICANN.