# Example: Using DHCPv6 Local Address Pools for Prefix Delegation over non-PPP Links

When a customer premises equipment (CPE) or requesting router and the provider edge (PE) router are connected using a PPP link, one of the following pool names is used to determine the IPV6 local address pool to be used for DHCPv6 Prefix Delegation to the CPE:

- The pool name returned by the RADIUS server in the Framed-IPv6-Pool attribute
- The pool name configured in the AAA domain map

However, for a CPE that is connected to the PE router using a non-PPP link, such as Ethernet, VLAN, or S-VLAN, the method for authentication of clients for DHCPv6 Prefix Delegation is not available in JunosE Release 10.1.x. In such cases, you can select the pool to be used for delegation of prefixes to the CPE by ensuring that the address of the interface over which the DHCPv6 request is received corresponds to any one of the prefix ranges in the configured local address pool.

The following example shows how you can configure an interface with an IPv6 address that matches a prefix configued in an IPV6 local address pool to enable allocation of prefixes from the configured pool for client requests over non-PPP links.

! Configure an IPv6 local address pool named example. Specify the IPv6 prefix! range from which prefixes can be delegated to DHCPv6 clients by specifying an! IPv6 prefix and the assigned prefix length. Configure the prefix 4004:4004::/48! to be excluded from being allocated to the requesting client. Exit the IPv6 Local! Pool Configuration mode.host1(config)#ipv6 local pool example host1(config-v6-local)#prefix 4004:4004::/32 48 host1(config-v6-local)#exclude-prefix 4004:4004::/48 host1(config-v6-local)#exit! ! Create a loopback interface with the IPv6 address matching that of a prefix range ! configured in the example local pool. Exit the Interface Configuration mode. host1(config)#interface loopback 1 host1(config-if)#ipv6 address 4004:4004::1/48 host1(config-if)#exit ! ! Create a Gigabit Ethernet interface and assign VLAN as the encapsulation! method. Exit the Interface Configuration mode. host1(config)#interface gigabitEthernet 2/1/4 host1(config-if)#encapsulation vlan host1(config-if)#exit! ! Create a VLAN subinterface, assign a loopback address to it, and enable! IPv6 Neighbor Discovery. Exit the Interface Configuration mode. host1(config)#interface gigabitEthernet 2/1/4.100 host1(config-if)#vlan id 100 host1(config-if)#ipv6 unnumbered loopback 1 host1(config-if)#ipv6 nd host1(config-if)#exit

When the PE router receives a request for DHCPv6 Prefix Delegation over the gigabit Ethernet interface 2/1/4.100, prefixes are allocated to the client from the example local pool. In this example, the local pool to use for allocation of prefixes is selected based on the IPv6 address of the interface over which the request is received.