Interface identifiers identify interfaces on a link.
As long as the interfaces are attached to different subnets, you can use the same identifier on more than one interface on a single node.
The IPv6 interface ID is as unique as the MAC address.
The interface ID is derived by a formula that uses the link layer 48-bit MAC address. In most cases, the interface ID is a 64-bit interface ID that contains the 48-bit MAC address. If you enter less than 64 bits, the system adds leading zeroes to extend the interface ID length to 64 bits.
Manual configuration
DHCPv6 (can configure the whole address)
Automatic derivation from EUI-64 (MAC address or other HW serial)—enables serverless or stateless auto-configuration when combined with high order part of address learned from router advertisements
Pseudo-random generation (client privacy)—enables serverless or stateless auto-configuration when combined with high order part of address learned from router advertisements
The switch supports manual interface ID configuration or automatic derivation from EUI-64.
Note
You must manually specify the network prefix, regardless of the interface ID formation method.
For stateless autoconfiguration, the ID is 64 bits in length.
For more information about stateless autoconfiguration, see Host autoconfiguration.