Host autoconfiguration

The switch can automatically configure a host (node), and assign IPv6 addresses automatically. This process is called stateless address autoconfiguration (SLAAC). The neighbor discovery (ND) protocol performs autoconfiguration.

Stateless autoconfiguration enables serverless basic configuration of IPv6 nodes and renumbering from a mathematical perspective.

Stateless autoconfiguration uses the following equation:

Stateless autoconfiguration = network prefix (router advertisement) + IPv6 interface identifiers

Stateless autoconfiguration uses the network prefix information in the router advertisement and integrates this with the interface ID to form the node global address(es).

Note

Note

The switch cannot autoconfigure an IPv6 address local to itself because IPv6 routers do not process router advertisements in the same manner as hosts. That is, routers check only for consistency in information advertised in IPv6 Router Advertisements on the same link.
Tip

Tip

You must manually assign all addresses/prefixes local to the switch.

Assuming an EUI-64 based interface ID is used, the IPv6 interface address is created from the 48-bit (6-byte) MAC address as follows:

  1. EUI-64 hexadecimal digits 0xff-fe are inserted between the third and fourth bytes of the MAC address to obtain the EUI-64.

  2. The universal or local bit, the second lower-order bit of the first byte of the MAC address, is complemented.

For example, the IPv6 identifier for host A uses the MAC address 00-AA-00-3F-2A-1C.

To automatically assign an address, the following occurs:

  1. Convert to EUI-64 format

    00-AA-00-FF-FE-3F-2A-1C

  2. Complement the Universal/Local (U/L) bit.

    The first byte in binary form is 00000000. When the seventh bit is complemented, it becomes 00000010 (0x02).

    The result is 02-AA-00-FF-FE-3F-2A-1C or 2AA:FF:FE3F:2A1C.

Host A with MAC address 00-AA-00-3F-2A-1C, combined with network prefix 2001::/64 provided by router advertisement, uses an IPv6 address 2001::2AA:FF:FE3F:2A1C.

A host generates a link-local address with the prefix FE80 regardless of whether an IPv6 router is present or not.

The link-local address for a node with the MAC address 00-AA-00-3F-2A-1C is FE80::2AA:FF:FE3F: 2A1C.

The following list explains the states of an autoconfiguration address:

9039040-00 Rev AB