IPv6 Addressing Configuration

Duplicate Address Detection (DAD)

Operating Notes

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A verified link-local unicast address must exist on a VLAN interface before the switch can run DAD on other addresses associated with the interface.

If a previously configured unicast address is changed, a neighbor adver­ tisement (an all-nodes multicast message--ff02::1) is sent to notify other devices on the VLAN and to perform duplicate address detection.

■IPv6 addresses on a VLAN interface are assigned to multicast address groups identified with well- known prefixes. For more on this topic, refer to “Multicast Application to IPv6 Addressing” on page 3-21.

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DAD is performed on all stateful, stateless, and statically configured unicast addresses, but not on Anycast addresses.

Neighbor solicitations for DAD do not cause the neighbor cache of neighboring switches to be updated.

If a previously configured unicast address is changed, a neighbor adver­ tisement is sent on the VLAN to notify other devices, and also for duplicate address detection.

■If DAD is disabled when an address is configured, the address is assumed to be unique and is assigned to the interface.

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