Hexadeci-what?  Last month our IPv6 Study Hall series brought you a study guide on how IPv6 addresses are distributed.  This month, we’re talking hexadecimal notation.  With increased IPv6 usage, you have probably seen IPv6 addresses, but you might not understand how to parse what you are seeing.  If you say “huh?” when you see this:  260F:03BA::/32, stay tuned for a quick intro to IPv6: hexadecimal notation and the structure of an IPv6 address.

First things first, let’s talk hexadecimals. IPv6 addresses are expressed as a series of eight 4-character hexadecimal numbers, which represent 16 bits each (which equals 128 bits total).

Here’s an example of a full IPv6 address:

2604:8000:0FC0:CF00:1234:5678:9ABC:DEF0

Let’s break it down:

2604: identifies ARIN’s block

8000: identifies the ISP’s /32 block

0FC0: identifies a specific site

CF00: identifies a specific subnet at that site

1234:5678:9ABC:DEF0 identifies a specific device on that subnet

Comparing IPv6 to IPv4

An IPv4 /8 is composed of 65,536 /24s, each of which can hold 256 devices (assuming one IP address per device), and parallel that to an IPv6 /32, which is composed of 65,536 /48s, each of which has 65,536 /64 subnets, each of which has a near-infinite number of IP addresses.  So, a fair comparison is to say that with an IPv4 /8, if you assign a /24 per site, you can number 65,536 sites, each of which gets 256 IP addresses.  With an IPv6 /32, you can support the same number of sites (65,536), but each has 65,536 subnets instead of 256 IP addresses.  So, in IPv6, every ISP gets something that’s effectively larger than the class A subnets, of which there are only a few in all of IPv4 (referring to classful networks), that were given out way back when.  This illustrates how massive the scale is of IPv6 in comparison to that of IPv4.

IPv6 host addressing

The least significant 64 bits (the 64 bits on the right) are basically for host auto configuration, so the device takes its MAC address, does some magic, and assigns itself its own last half of its IPv6 address.

Common block sizes for IPv6 addresses:

IPv6 addresses are distributed in blocks, just like IPv4.  Here is a breakdown of the most common allocation sizes.

/12 issued by IANA to ARIN

/32 issued by ARIN to an ISP (can also get a /28, /24, etc.)

Each RIR /12 has 1,048,576 /32s to assign to ISPs.

/48 assigned by an ISP to a customer site (end users may also request directly from ARIN)

Each ISP’s /32 has 65,536 /48s to assign to customer sites.

/64 to a subnet at the customer’s site

Each customer’s /48 has 65,536 /64 subnets.

Each /64 subnet contains more than 18 quintillion IPv6 addresses.

Thanks for joining us for this month’s IPv6 Study Hall, be sure to stop by for our next unit when we cover how ISPs can prepare for IPv6.

Get out your pencils and notebooks.  After reading the first post in our IPv6 Study Hall series, you know how to determine whether or not you qualify for IPv6 address space and how to apply for these addresses from ARIN.  Now we thought we’d deliver you a study guide on how the address distribution process works.

A hierarchical chain of organizations distributes Internet number resources, including IPv6 addresses. The Internet Assigned Numbers Authority (IANA) manages the global IP address pool, allocating large blocks of address space to the five Regional Internet Registries (RIRs). As a contracted function of the Internet Corporation for Assigned Names and Numbers (ICANN), IANA also manages domain names and number resources in addition to protocol assignments.

Each RIR, including ARIN, is recognized by the IANA to serve and represent large geographical regions. The RIRs follow community-based policies in allocating Internet number resources within their respective regions. These five RIRs are:

• African Network Information Centre (AFRINIC) – Africa
• American Registry for Internet Numbers (ARIN) – Canada, many Caribbean and North Atlantic islands, and the United States
• Asia-Pacific Network Information Centre (APNIC) – the entire Asia Pacific, comprising 56 economies throughout Asia and Oceania.
• Latin America and Caribbean Network Information Centre (LACNIC) – Latin America and parts of the Caribbean region
• Réseaux IP Européens Network Coordination Centre (RIPE NCC) – Europe, the Middle East, and parts of Central Asia

After receiving large blocks of address space from IANA, the RIRs allocate small blocks of IP addresses to large network operators in their respective regions, including enterprise organizations and Internet Service Providers (ISPs). Organizations that receive an allocation from an RIR can further allocate IP addresses to other network operators or to end-users.

Micro-allocations

ARIN makes micro-allocations to critical infrastructure providers of the Internet, including public exchange points, core DNS service providers as well as other RIRs and IANA. Organizations that currently hold IPv6 allocations may also apply for a micro- allocation for internal infrastructure.

Want to see how many IPv6 addresses have been allocated by ARIN in 2012? Visit our  Statistics Page and scroll down to the IPv6 section. For more information on the IPv6 allocation process, take a look at the “Policies for allocations and assignments” in the ARIN Number Resource Policy Manual (NRPM).

Be sure to join us next month when our IPv6 Study Hall blog series will tackle the subject of IPv6 from the ground up.

Welcome to our new blog series, “IPv6 Study Hall”. This series will serve as an open learning forum for those of you seeking resources and information about IPv6.

We don’t want to give you flashbacks to your dreaded ninth grade homeroom class, but we do want to offer up quality resources that can help answer any questions you may have about IPv6. So follow along with us on the third Tuesday of every month as we clarify a few commonly asked questions about IPv6 deployment.

First up, we’ll start with the basics—how to apply for an IPv6 address from ARIN.

Of course, before you even request allocation, you need to make sure you qualify. Review our number resource policies regarding IPv6 to ensure your organization meets the requirements. Take note that our policy guidelines for an organization approaching its allocation justification request for IPv6 are a bit different than what was required for IPv4.

Organizations can justify addressing devices within their network by showing intent for the addresses to begin operational use within 12 months as well as by meeting one of the criteria listed here.

An initial size allocation will be based off the largest site you operate. For large organizations (if you have more than 49,152 sites), you’ll need to read the details in our ISP Address Space Guidelines.

Next, register for a Point of Contact (POC) and an Organization Identifier (Org ID) before submitting a request through your ARIN Online account. You will also need to have an officer of the company verify to ARIN that the data you submitted is accurate.

Once ARIN notifies you that you have been approved, you must follow up on your request within 90 days, or else resubmit your request. You will need to complete an Initial IPv6 Allocation Billing form before ARIN can allocate your new address block.

More information on how to request IPv6 address space from ARIN can be found here.

There you have it—how to apply for IPv6 addresses from ARIN. Next up on our IPv6 Study Hall series we’ll take a look at how IPv6 addresses are distributed. We’ll be taking attendance again next month, so don’t be late!