When an interface becomes enabled the Node forms a link-local address . An interface may become enabled after any of the following events:
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The interface is initialized at system startup time. |
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The interface is reinitialized after a failure or it was disabled. |
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The interface attaches to a link for the first time. |
A link-local address is formed by appending the well-known link-local prefix FE80::0 to the interface identifier.
If the interface identifier has a length of N bits, the interface identifier replaces the right-most N zero bits of the link-local prefix.
In case that the interface identifier is more than 118 bits in length, autoconfiguration fails and it should be manual configured.
Interface identifiers will typically be 64-bits long and based on EUI-64 identifiers. (you can read more about it in RFC 2373).
A link-local address has an infinite preferred and valid lifetime; it is never timed out.
