IPv6 Addressing Configuration
Configuring a Static IPv6 Address on a VLAN
Statically Configuring a Link-Local Unicast Address
Syntax: [no] ipv6 address fe80::< device-identifier> link-local
■If IPv6 is not already enabled on the VLAN, this command enables IPv6 and configures a static link-local address.
■If IPv6 is already enabled on the VLAN, then this command overwrites the current, link- local address with the speci fied static address. (One link-local address is allowed per VLAN interface.)
<device-identifier>: The low-order 64 bits, in 16-bit blocks, comprise this value in a link-local address:
xxxx xxxx : xxxx xxxx : xxxx xxxx : xxxx xxxx
Where a static link-local address is already configured, a new, autoconfigured global unicast addresses assignment uses the same device identifier as the link-local address.
Notes: An existing link-local address is replaced, and is not deprecated, when a static replacement is configured.
The prefix for a statically configured link-local address is always 64 bits, with all blocks after fe80 set to zero. That is: fe80:0:0:0.
After verification of uniqueness by DAD, a statically config ured link-local address status is set to preferred, with a perma nent lifetime. (Refer to “IPv6 Address Deprecation” on page 3 25.)
For link-local addressing, the no form of the static IPv6 address command produces different results, depending on how IPv6 is configured on the VLAN:
■If IPv6 was enabled only by a statically configured link- local address, then deleting the link-local address disables IPv6 on the VLAN.
■If other IPv6-enabling commands have been configured on the VLAN, then deleting the statically configured link-local address causes the switch to replace it with the default (EUI-64) link-local address for the VLAN, and IPv6 remains enabled. (For more on the EUI-64 address format, refer to “Extended Unique Identifier (EUI)” on page 3-14.)
Refer also to “Disabling IPv6 on a VLAN” on page 4-16.
