IPv6 ESM hosts are only supported in the Routed CO model (both VPRN and IES).
At the IPv6 node under the subscriber interface level, the length of the prefixes that are offered is defined through the delegated-prefix-length option. This setting is fixed for the subscriber interface and cannot be changed after subscriber prefixes are defined.
Subscriber prefixes define the ranges of addresses that are offered on this subscriber interface. By default, only these subscriber prefixes are exported to the routing protocols to keep the routing tables small. There are three types of subscriber interfaces:
wan-host
A range of prefixes that are assigned to PPPoE hosts and as DHCPv6 IA_NA addresses. These prefixes are always /64.
pd
A range of prefixes that are assigned as DHCPv6 IA_PD prefixes for DHCPv6 IPoE clients and for PPPoE RGs. The length of these prefixes is defined by the delegated-prefix-length.
both
When both 'wan-host' and 'pd' are defined, the subscriber prefix is a range that can be used for both previous types. However, the delegated-prefix-length is restricted to /64 in this case.
The subscriber interface prefix can also be provisioned through RADIUS. The RADIUS VSA Alc-IPv6-Sub-If-Prefix requires a prefix and the prefix type. The prefix type can be pd, wan, or both. The prefix is then installed on the subscriber interface where the subscriber is instantiated. The prefix state is tied to the state of the subscriber. After the subscriber session ends, the prefix is removed from the subscriber interface and subsequently from both the FDB and the RIB. This feature can be used as an alternative to unnumbered subscriber interfaces, where the subscriber interface prefix does not need to be predetermined. However, by installing the prefix after authentication, the subscriber interface becomes numbered. In an unnumbered subscriber interface all subscriber routes are installed whereas in a numbered subscriber interface only the subscriber interface prefix is advertised, therefore reducing the number of advertised routes significantly. The RADIUS-installed prefix can then be advertised through a routing protocol. Subscriber interface prefixes are under the protocol direct type similar to other router interfaces. To advertise only the subscriber interface prefix installed by RADIUS, origin aaa can be used in the router policy.
The IPv6 node under the group interface contains the DHCPv6 proxy configuration and the router advertisement configuration.