Hierarchical IPv6 addressing plan builder GestióIP
IP address management software

How to create a hierarchical IPv6 addressing plan

This document describes how to design a hierarchical IPv6 addressing plan on the basis of an example of a multinational organization with the help of the free online Hierarchical Addressing Plan Builder.

In our example we create the first subnet levels of the address allocation scheme from the organizations Locations and the last subnet level from the Use Type of the networks. You can use the Hierarchical Addressing Plan Builder to create other types of allocation schemes like pure Location based or pure Use Type (functional) based, too.

Some goals of such a mixed approach are:


The organization consist in one campus in New York, two campi in Berlin and 10 offices in different cities in North-America, Europe and Asia.

A hierarchical structure for the organization could consist in:


When we associate the organizations topology with the different levels we get the following table:

Level I (Contient) Level II (Land) Level III (City) Level IV (Campus) Level V (Building) Level VI (Network environment)
North America USA NY Campus NY Building 1 production
pre-production
development
corporate
...
Building 2 production
pre-production
development
corporate
...
Washington Office Wash (no campus) Office Wash production
pre-production
development
corporate
...
Canada Toronto Office Toro (no campus) Office Toro production
pre-production
development
corporate
...
Europe Germany Berlin Campus I Berlin Building 1 production
pre-production
development
corporate
...
Building 2 ...
Building 3 ...
Building 4 ...
Building 5 ...
Campus II Berlin Building 1 ...
Building 2 ...
Hamburg Office 1 Ham (no campus) Office 1 Ham ...
Office 2 Ham (no campus) Office 2 Ham ...
Munich Office Mun (no campus) Office Mun ...
England London Office Lon (no campus) Office Lon ...
Spain ...
France ...
Asia Japan ...
India ...
...
Table 1: Organization's topology


Now lets build the addressing plan.

In the first step we need to define what prefix length (how many networks) we want to use for every network level. In the second step we assign the organization's Locations to the different network levels and create the addressing plan. The addressing plan can be exported to CSV-format (coma separated value) which can easily be imported into a spreadsheet application or an IP address management (IPAM) system like GestióIP.


The ISP assigned the IPv6 network 2001:DB8::/32 to the organization.

With the infrastructure above we need at least:


Access to the Hierarchical Addressing Plan Builder and calculate the from your ISP assigned address 2001:DB8::/32


subnet calculator


The tool displays a list of possible level I networks.

prefix length explication

The first number (2) is the number of possible networks, the second number (/33) the prefix length of the networks for this level.


We need at least 3 level I networks to map the actual topology (three continents: North America,Europe,Asia).

Now we have to take future growing in mind. Actually the organization has buildings on three continents. So we need at least three level I networks. As a prefix length of /33 only offers two level I networks we need to choose at least a prefix length of /34, which offers four level I networks. But the organization may open in the future offices in Sydney (Australia) and Buenos Aires (South-America), so a prefix length of /34 would not offer sufficient networks for the future structure. Because of this we choose a prefix length of /35 with offers up to eight level I networks.

level I


We need at least 4 level II networks for the lands per continents. As a prefix length of /37 allows exact 4 level II networks and therefor does not offer free networks for future growing, we choose a prefix length of /39 with allows 16 subnets

level II


We need at least 3 level III networks for the cities per land. A prefix length of /41 allows only up to 4 level III networks (cities) per land. We choose here a prefix length of /42 (8 networks) to take futur growing in mind.

level III


We need at least 2 level IV networks for the campi per city. We choose a prefix length with offers us 4 networks for campi per city.

level IV


We need at least 5 level V networks for the buildings per campus.

level V


We need at least 10 level VI networks for the different network environments per building.

level VI


We need at least 351 level VII networks per network environment. The networks of the last level (networks which contains hosts) should always have a prefix length of /64.

level VII


Click "CREATE PLAN" to access to the Hierarchical Addressing Plan Builder.

create addressing plan


In the second step we map organization's topology to the different network levels and create the addressing plan.

Level I: continents

hierarchical plan level I


Level II: lands

hierarchical plan level II


Level III: cities

hierarchical plan level III


Level IV: campi

If there is just a single office and no campus in the city we use the office as level IV and as level V category.

hierarchical plan level IV


Level V: buildings

hierarchical plan level V


Level VI: network environments

It's recommended to use the same network environments for every building independently if the network environment exists in the building or not. That permits a standarized nummeration of the networks and gives us the possibility to recognize the network environment directly from the IP address.

hierarchical plan level VII


Level VII: networks per network environment

Introduce the number of networks (/64) which should be created for every network environment. Leave the "number of networks" fields blank for the network environments which do not exists within a building. In our example building 1 of campus 1 in New York contains parts of the marketing and human recurse department and no production or preproduction networks.

hierarchical plan level VII

After you have determined how many networks should be created for every network level press "send" at the bottom of the page to create the addressing plan.


The addressing plan will be presented in form of a list.

hierarchical IPv6 addressing plan

Note: only the first 20 /64 (last level) networks will be displayed in this view. Use the "export" button at the end of the page to export the entire IPv6 addressing plan.


And how can I recognize to which continent, city or network environment a network belongs to?

In our example the significant bits for the continents (level I, prefix length /35) are the first three bits of the third address octet: 2001:0db8:0000:0000:0000:0000:0000:0000 (see Table 2)

Networks in North America always have this bits set to 0: 2001:0db8:0000:0000:0000:0000:0000
Networks in Europe always have this bits set to 2: 2001:0db8:2000:0000:0000:0000:0000

The significant bits for the network environment (level VI, prefix length /53) are the five first bits of the fourth address octet: 2001:0db8:0000:0800:0000:0000:0000:0000

Production networks always have this bits set to 00: 2001:0db8:0000:0000:0000:0000:0000:0000 (independently if the are in New York, Berlin or Hong Kong)
Pre-production networks always have this bits set to 08: 2001:0db8:0000:0800:0000:0000:0000:0000 and
Marketing networks always have this bits set to 30: 2001:0db8:0000:3000:0000:0000:0000:0000

So if we see the address 2001:0db8:20a6:08e3:0000:0000:0000:0000 we know that this is a pre-production network in Europe.


Table 2 shows the distribution of the significant bits for all levels:

LevelPrefix lengthhexadecimal addressthird and fourth octet in binary (P=2001:0db8)
I352001:0db8:0000:0000::P:0000 0000 0000 0000:0000 0000 0000 0000::
II392001:0db8:0000:0000::P:0000 0000 0000 0000:0000 0000 0000 0000::
III422001:0db8:0000:0000::P:0000 0000 0000 0000:0000 0000 0000 0000::
IV442001:0db8:0000:0000::P:0000 0000 0000 0000:0000 0000 0000 0000::
V482001:0db8:0000:0000::P:0000 0000 0000 0000:0000 0000 0000 0000::
VI532001:0db8:0000:0000::P:0000 0000 0000 0000:0000 0000 0000 0000::
VII642001:0db8:0000:0000::P:0000 0000 0000 0000:0000 0000 0000 0000::
Table 2: Distribution of level significant bits


Nibble boundaries

As you see in the table, some four-bits-blocks of our example allocation scheme are significant for more than one level (assignments made on non-nibble boundaries). If you need that your address allocation scheme respects the nibble boundaries, assign only the following prefix lengths: ...28, 32, 36, 40, 44, 48, 52, 56, 60, 64 (prefix length divisible by 4). That would make sure that the significat bits always appear in blocks of four bits (a prefix length of e.g. /32 means, that you use the first 32 bits of the IPv6 address for the prefix part).

LevelPrefix lengthhexadecimal addressthird and fourth octet in binary (P=2001:0db8)
I362001:0db8:0000:0000::P:0000 0000 0000 0000:0000 0000 0000 0000::
II402001:0db8:0000:0000::P:0000 0000 0000 0000:0000 0000 0000 0000::
III522001:0db8:0000:0000::P:0000 0000 0000 0000:0000 0000 0000 0000::
IV642001:0db8:0000:0000::P:0000 0000 0000 0000:0000 0000 0000 0000::
Table 3: Example of an allocation scheme that respects the nibble boundaries



Exporting the addressing plan

It's possible to export the IPv6 addressing plan to CSV format which can be imported with a spreadsheet application (e.g. Libre Office Calc, MS Excel). Click "export" to export the addressing plan. Open it directly with a spreadsheet application or save it to your disk. Choose "Comma" as separator and UTF-8 as character set when importing the CSV file.

import addressing plan to CSV


addressing plan spreadsheet


Note: CSV data will be dynamically created and directly be streamed. No data will be saved on the server.



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