Configuring an IPv6 discovery prefix

Configure the discovery prefixes to send in router advertisement.

About this task

Hosts on the link use router advertisements to perform IPv6 autoconfiguration.

The discovery prefix controls which IPv6 addresses will be automatically configured, and for how long they are valid.

Procedure

Enter Interface Configuration mode:

enable

configure terminal

interface GigabitEthernet {slot/port[/sub-port][-slot/port[/sub-port]][,...]} or interface vlan <1–4059>

Note

If the platform supports channelization and the port is channelized, you must also specify the sub-port in the format slot/port/sub-port.
Create neighbor discovery prefixes for an interface:

ipv6 nd prefix-interface WORD<0–255> [eui <1–3>] [no-advertise] [no-autoconfig] [no-onlink]
Modify an existing neighbor discovery prefix:

ipv6 nd prefix WORD<0–255> infinite [no-advertise] [preferred-life <0-4294967295>] [valid-life <0-4294967295>]

Example

Create a new neighbor discovery prefix:

Switch:1(config-if)#ipv6 nd prefix-interface fd48:bfb6:4c09:9499::1/64

Variable definitions

Use the data in the following table to use the ipv6 nd prefix and ipv6 nd prefix-interface commands.


Variable	Value
eui `<1–3>`	Configures the EUI address. The values are: (1) EUI not used (2) EUI with Universal/Local bit (U/L) complement enabled (3) EUI used without U/L Use an EUI-64 interface ID in the address field. If enabled, use EUI, or use EUI-64 and the complement Universal/Local (U/L) bit. This operation provides for both global– and link-local addresses. After you create the entry, you cannot modify this value. This value is valid for use only when the prefix length is 64 or less. The default is EUI not used. If you select EUI not used, this configuration creates an IPv6 ND prefix but no associated IPv6 address on the router. IF you select either EUI used with UL complement or EUI used without UL complement, an associated IPv6 adress is created by concatenating the specified prefix with the EUI-64 interface ID.
infinite	Configures the prefix valid lifetime so it never expires. The default is disabled, which means the prefix expires.
no-advertise	Removes the prefix from the neighbor advertisement. The default is disabled, which means the prefix is advertised.
no-autoconfig	Configures the prefix for use as the autonomous address configuration. This value is placed in the autoflag field in the prefix information option. The value is a 1-bit flag. The default is enabled.
no-onlink	Configures the prefix for use when determining if a node is online. This value is placed in the L-bit field in the prefix information option. The value is a 1-bit flag. The default is enabled.
preferred-life `<0–4294967295>`	Configures the preferred lifetime in seconds that indicates the length of time this prefix is advertised. The default value is 604800. The preferred lifetime is the length of time for the tentative, preferred, and depreciated state of an autoconfiguration address. The preferred lifetime value must be less than the valid lifetime value. If you must configure the valid lifetime value to a value lower than the current preferred lifetime, you must lower the preferred lifetime value first.
valid-life `<0–0-4294967295>`	Configures the valid lifetime in seconds that indicates the length of time this prefix is advertised. The default is 2592000. A valid lifetime is the length of time of the preferred and depreciated state of an autoconfiguration address. The preferred lifetime value must be less than the valid lifetime value. If you must configure the valid lifetime to a value lower than the current preferred lifetime, you must lower the preferred lifetime value first.
WORD `<0–255>`	Specifies the IPv6 address and prefix.

Use the data in the following table to use the interface command.


Variable	Value
`<1-4059>`	Specifies the VLAN ID in the range of 1 to 4059. By default, VLAN IDs 1 to 4059 are configurable and the system reserves VLAN IDs 4060 to 4094 for internal use. On switches that support the vrf-scaling and spbm-config-mode boot configuration flags, if you enable these flags, the system also reserves VLAN IDs 3500 to 3998. VLAN ID 1 is the default VLAN and you cannot create or delete VLAN ID 1.
{slot/port[/sub-port][-slot/port[/sub-port]][,...]}	Identifies the slot and port in one of the following formats: a single slot and port (slot/port), a range of slots and ports (slot/port-slot/port), or a series of slots and ports (slot/port,slot/port,slot/port). If the platform supports channelization and the port is channelized, you must also specify the sub-port in the format slot/port/sub-port.