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3.1. Format

3.1. Format​

The Local IPv6 addresses are created using a pseudo-randomly allocated global ID. They have the following format:

| 7 bits |1|  40 bits   |  16 bits  |          64 bits           |
+--------+-+------------+-----------+----------------------------+
| Prefix |L| Global ID  | Subnet ID |        Interface ID        |
+--------+-+------------+-----------+----------------------------+

Where:

  • Prefix — FC00::/7 prefix to identify Local IPv6 unicast addresses.

  • L — Set to 1 if the prefix is locally assigned. Set to 0 may be defined in the future. See Section 3.2 for additional information.

  • Global ID — 40-bit global identifier used to create a globally unique prefix. See Section 3.2 for additional information.

  • Subnet ID — 16-bit Subnet ID is an identifier of a subnet within the site.

  • Interface ID — 64-bit Interface ID as defined in [ADDARCH].

See 3.1.1. Background.

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