Menu option: Design > IPv6

Make sure that the Welcome tab, then the Allocation tab is selected.

The Allocation tab is where you generate subnets for devices or interfaces at a selected site or sites.

To generate ULA subnets:

1. Select the site or sites that you want to allocate subnets for. To select all sites, click on the check box next to the Site ID header.
2. Click on Generate IPv6 Plan.

3. Click on the ULA tab. The following screen opens:

   

4. Select the ULA Parent Block from the drop-down list.
5. At ULA Global ID Selection Method, select one of the following:
   Pseudo-random algorithm (RFC 4193) - use a MAC address to generate the Global ID. For details, see Global IDs in Virtual SME
   Cryptographically secure random generation - use a random secret key to generate the Global ID. For details, see Global IDs in VirtualSME
   Manual/custom entry - for this selection, you will have your own Global ID.
6. Select one of the following:
   Single /32 for Entire Organization - one /32 ULA prefix will be subdivided across all sites.
   One /32 per Site - each site receives its own dedicated /32 ULA prefix.
7. At SUBNET SIZE PER SITE, enter the required subnet size. The maximum number of available subnets displays alongside.
8. Enter the Number of Ranges from the drop-down list. The number of subnets that can be created is displayed alongside your selection.
9. Select the Allocation Strategy from the drop-down list. The options are:
   Conservative - 50% of the addresses will be reserved for future use.
   Moderate - 30% of the addresses will be reserved for future use.
   Aggressive - 10% of the addresses will be reserved for future use.
10. Check that the Allocation Preview is as required
11. Click on Generate Plan.
     

Global IDs in Virtual SME

A Global ID is a 40-bit unique number that you can use to help to create a ULA IPv6 address, ensuring that even though ULAs are private, they remain globally unique if networks merge or get acquired, preventing address conflicts.

A ULA IPv6 address is made up as follows:

So, how do you obtain a Global ID?

Generating a Global ID

To obtain a Global ID:

1. Obtain the current time of day in 64-bit NTP format.

2. Obtain a EUI-64 identifier from the system on which you are performing this allocation.
   
   For the pseudo-random algorithm method, if an EUI-64 identifier does not exist, you can create one from a 48-bit MAC address. This can be any random organisational or site-specific MAC address, unless you are allocating to a specific device. (You can use an online EUI-64 calculator.)

   For the cryptographically secure random generation, if an EUI-64 identifier does not exist, you can use any randomly generated number.  (You can use an online EUI-64 calculator.)

3. Concatenate the time of day with the EUI-64 identifier to create a unique key.
4. Generate an SHA-1 digest on this key to create a 160 bit key.
5. Use the least significant bits as your 40-bit Global ID.