Stateless Address Autoconfiguration (SLAAC)

[zwelch121]

How can SLAAC (Stateless Address Configuration) generate a Global Unicast IPv6 address?

I was reading some documentation on IPv6 that said SLAAC can be used to generate a global unicast IPv6 address. How can a node use SLAAC to generate a global unicast address if it has not been registered through IANA? If it really does use SLAAC to generate a Global Unicast address please enlighten me.

Thanks

-Zachary

[Traian Bratescu · Accepted solution]

Hi,

The basic idea is that the router has a public IPv6 address form which the host derives the network portion of the address and then generates an EUI-64–derived interface identifier.

The full process bellow

(generate link-local address)

1.A tentative link-local address is generated: FE80::/64 plus EUI-64 interface identifier.
2. Duplicate address detection is performed
3. If no Neighbor Advertisement message the link-local address is initialized for the interface.

(generate global address)

4. Host sends a Router Solicitation message.
5. If a Router Advertisement message is received, the hop limit, reachable time, retransmission
timer, and maximum transmission unit (if that option is present) are set.
6. For each Prefix Information option present, the following actions occur:
a. If the On-Link flag is set to 1, the prefix is added to the prefix list.
b. If the Autonomous flag is set to 1, the prefix and an appropriate interface identifier are
used to derive a tentative address.
c. Duplicate address detection is used to verify the uniqueness of the tentative address.
d. If the tentative address is in use, the use of the address is not initialized for the interface.
e. If the tentative address is not in use, the address is initialized.

[zwelch121]

Thank you for your informative answer!

[rosaho]

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