Configuring Shared IPv6 Interfaces

You can create multiple shared IPv6 interfaces over the same layer 2 logical interface—for example, atm 5/3.101—enabling more than one IPv6 interface to share the same logical resources.

To share IPv6 interfaces:

Create a layer 2 interface.
host1(config)#interface atm 5/3 host1(config-if)#interface atm 5/3.101
(Optional) Create a primary IPv6 interface.
host1(config-if)#ipv6 address 1::1/64 host1(config-if)#exit
Create the shared IPv6 interface.
host1(config)#interface ipv6 si0
Associate the shared IPv6 interface with the layer 2 interface by the following method:
host1(config-if)#ipv6 share-interface atm 5/3.101
To fully configure the shared interface, assign an address (or make the interface unnumbered).
host1(config-if)#ipv6 address 1::1/64

interface ipv6

Use to create an IPv6 interface for interface sharing.
Use the specified name to refer to the shared IPv6 interface; you cannot use the layer 2 interface to refer to them, because the shared interface can be moved.
Example
host1(config)#interface ipv6 si1
Use the no version to delete the IPv6 interface.
See interface ipv6

ipv6 share-interface

Use to specify the layer 2 interface used by a shared IPv6 interface. The command fails if the layer 2 interface does not yet exist. The command is not supported (that is, it fails) if you use an RSVP tunnel (for example, tunnel mpls:1) to identify the layer 2 interface.
After creating the shared IPv6 interface, you can configure it as you do any other IPv6 interface.
The shared interface is operationally up when the layer 2 interface is operationally up.
You can create operational shared IPv6 interfaces in the absence of a primary IPv6 interface.
Example
host1(config-if)#ipv6 share-interface atm 5/3.101
Use the no version to remove the association between the layer 2 interface and the shared IPv6 interface. You can delete shared and primary IPv6 interfaces independently.
See ipv6 share-interface