The Prefix Delegation (PD) prefix is included in the accounting messages using the VSA [99], Framed-IPv6-Route attribute with the string type ‟pd-host” appended to differentiate it from a regular framed IPv6 route; for example, FRAMED IPV6 ROUTE [99] 39 2001:1000::/64 :: 0 pref 0 type pd-host. PD as a managed route is applicable to both PPP and IPoE sessions and can point either to an IPv4 host or to an IPv6 WAN host.
Table: RADIUS accounting behavior describes the RADIUS accounting behavior based on the session type and the next-hop host.
| Session type and next-hop host | RADIUS accounting start | RADIUS accounting interims | RADIUS accounting stop |
|---|---|---|---|
PPP session with IPv6 PD pointing to IPv4 host as the next hop |
A PPP connection triggers an accounting start |
A DHCP NA+PD solicit triggers an interim update for the PD host with interim reason ‟delegated-ipv6-prefix-up” and the prefix included in the VSA Framed-IPv6-Route A DHCP PD solicit triggers an interim update for the PD host with interim reason delegated-ipv6-prefix-up and the prefix included in the VSA framed-ipv6-route Restriction: A DHCP PD lease expire triggers an interim update with interim reason ‟delegated-ipv6-prefix-down”; however, the VSA framed-ipv6-route is not included |
A PPP disconnect with only the IPv4 and IPv6 PD host triggers an accounting stop with the prefix included in the VSA Framed-IPv6-Route Restriction: A PPP disconnect with the IPv4, NA, and PD host without session-optimized-stop enabled, is not include the VSA Framed-IPv6-Route |
PPP session with IPv6 PD pointing to IPv6 NA host as the next hop |
A PPP connection triggers an accounting start. It is possible to have a single-stack IPv6-only session |
A DHCP NA+PD solicit triggers an interim update for the PD host with interim reason delegated-ipv6-prefix-up and the prefix included in the VSA framed-ipv6-route Restriction: A DHCP PD lease expire triggers an interim update with interim reason ‟delegated-ipv6-prefix-down”; however, the VSA FramedIPv6-Route is not included |
A PPP subscriber disconnect triggers an accounting stop with the PD host prefix included in the VSA Framed-IPv6-Route |
IPoE session with IPv6 PD pointing to IPv4 host as the next hop |
A DHCPv4 or a DHCPv6 request (DHCPv6 always performs NA and PD requests together) triggers the accounting start |
A DHCP PD is always performed together with NA. The PD is not in the start message but is included in the accounting interim update as a part of the host update. If the DHCPv4 lease expires, the interim update contains the PD prefix in the VSA framed-ipv6-route Restriction: A DHCP PD lease expire triggers an interim update with interim reason ‟delegated-ipv6-prefix-down”; however, the VSA Framed-IPv6-Route is not included |
If only the IPv4 host and PD host remain, the release of the DHCPv4 triggers an accounting stop with the PD host prefix included in the VSA Framed-IPv6-Route Restriction: If the DHCPv4 is released and an IPv6 NA host remains, the IPv6 lease release/expire is an interim update that does not include the prefix |
IPoE session with IPv6 PD pointing to IPv6 NA host as the next hop |
A DHCPv4 or a DHCPv6 request (DHCPv6 always performs NA and PD requests together) triggers the accounting start. It is possible to have a single-stack IPv6-only session |
A DHCP PD is always performed together with NA. The PD is not in the start message but is included in the accounting interim update as a part of the host update. Restriction: A DHCP PD lease expire triggers an interim update with interim reason ‟delegated-ipv6-prefix-down”; however, the VSA Framed-IPv6-Route is not included |
If only the IPv6 subscriber is left, the release of NA contains the prefix of the PD host Restriction: If the DHCPv6 is released and an IPv4 host remains, the IPv6 lease release/expire is an interim update that does not include the prefix |
RADIUS per host accounting:
In SR OS, the accounting paradigm is based on SLA profile instances yet this is at odds with traditional RADIUS authentication and accounting which is host-centric. In previous SR OS releases, it was possible to have many hosts sharing a common SLA profile instance, and therefore accounting and QoS parameters. Complications arose with RADIUS accounting because Accounting-Start and Accounting-Stop are a function of sla-profile instance and not the hosts. This meant that some host-specific parameters (like framed-ip-address) would not be consistently included in RADIUS accounting.
Currently, dual-stack subscribers are really two different hosts sharing a single sla-profile instance. A new RADIUS accounting mode has been introduced to support multiple-host environments.
Under accounting-policy, a host-accounting command allows configurable behavior.