You can configure Carrier Grade Network Address Translation (CGN) as an independent feature or use CGN along with broadband
Broadband access aggregation enables connections between multiple technologies such as cable, digital subscriber line (DSL),
Ethernet, ISDN, and wireless devices that are connected to corporate VPNs, third-party applications, and the Internet.
PPP over Ethernet (PPPoE) connects hosts on a network over a simple bridging device to a remote aggregation concentrator.
PPPoE is the predominant access protocol in broadband networks worldwide.
For PPPoE to work with CGN, either the virtual templates or the RADIUS server must provide the Network Address Translation
(NAT) inside configuration. The NAT inside configuration can be downloaded as part of the RADIUS authentication or alternatively
configure the ip nat inside command on the virtual template. This gets cloned into a virtual access interface that inherits the ip nat inside configuration.
For the RADIUS server to provide the NAT inside configuration, configure the aaa policy interface-config allow-subinterface global command or configure the Cisco attribute-value pairs (AV pairs) lcp:allow-subinterface=yes and then include lcp:interface-config=ip nat inside in the RADIUS profile on a per-subscriber basis.
You can terminate a PPPoE session either in the global routing table or at a VRF instance.
CGN supports dual-stack (IPv4 and IPv6) PPP sessions. However, only IPv4 traffic is subject to NAT. The IPv6 traffic is not
translated; it is routed as per the IPv6 routing configuration.