# PPP Accounting Statistics

JunosE accounting for tunneled subscribers at the L2TP LAC counts the payload that PPP passes to or receives from L2TP for transport. At this stage in the protocol processing, any padding outside PPP, such as that for PPPoE, has been removed. Accounting includes the authentication acknowledgement packet, CHAP success packets, and PAP acknowledgment packets. Accounting ends when L2TP has been notified to terminate the session. The statistics are reported in the following RADIUS attributes:

Attribute Number | Attribute Name
--- | ---
42 | Acct-Input-Octets
43 | Acct-Output-Octets
47 | Acct-Input-Packets
48 | Acct-Output-Packets

Termination of a tunneled session can result from PPP termination, L2TP shutdown, subscriber logout, or lower layer down events. When the session is terminated through PPP, the software counts both the PPP terminate-request and the PPP terminate-acknowledgement packets.

- Accounting statistics reported in RADIUS octet counts (Acct-Input-Octets and Acct-Output-Octets) for tunneled PPP customers at the L2TP LAC include the following data:
  - All upper layer control traffic, including IPCP, IPCPv6, OSICP, and MPLSNCP
  - All data traffic, including IP, IPv6, MPLS, and OSI
  - PPP PAP or CHAP acknowledgments. and also retransmission of PAP or CHAP that take place after the session is active (even when proxy authentication is accepted)
  - All PPP PAP or CHAP negotiations in the case where proxy authentication is disabled or required to renegotiate at the LNS
  - All LCP traffic when proxy LCP is disabled or required to renegotiate at the LNS
  - All PPP LCP echo requests and their responses
  - PPP LCP terminate-request or terminate-acknowledgement packets from the client or LNS when PPP initiates termination of the session
  - If present, the two PPP header bytes (Address Field 0xFF and Control Field 0x03) as part of the L2TP payload
- Accounting statistics reported in RADIUS octet counts (Acct-Input-Octets and Acct-Output-Octets) for tunneled PPP customers at the L2TP LAC exclude the following data:
  - LCP when Proxy LCP is enabled and accepted at the LNS
  - Initial PPP PAP request
  - Initial PPP CHAP challenge and response
- Accounting statistics reported in RADIUS packet counts (Acct-Input-Packets and Acct-Output-Packets) for tunneled PPP customers at the L2TP LAC are based on packets delivered to or received from the L2TP session. These statistics exclude L2TP control traffic and L2TP hello messages.

For information on accounting statistics for terminated PPP sessions, see the PPP Accounting Statistics section in JunosE Link Layer Configuration Guide .