The value of Acct-Tunnel-Connection uniquely identifies an L2TP session. To match LAC and LNS accounting records, the value of Acct-Tunnel-Connection is determined by a method shared by LAC and LNS. This means for a specific L2TP session, Acct-Tunnel-Connection from the LAC and LNS are the same.
Current ESM statistics are used in tunnel link and tunnel level accounting. This applies to the standard attribute and the 7750 SR’s own VSA.
Tunnel level accounting statistics must aggregate all session statistics that belong to the tunnel.
There could be sessions come and go before tunnel is down, so system need to remember the stats of every session that has been created within the tunnel.
This applies for both standard attribute and 7750 SR’s own VSA.
The value of Acct-Tunnel-Packets-Lost is the aggregation of all discarded packets on both ingress and egress.
L2TP tunnel accounting on LAC can be enabled from RADIUS using the Alc-Tunnel-Acct-Policy VSA. This attribute overrides the locally configured L2TP RADIUS accounting policy.
See 7450 ESS, 7750 SR, and VSR RADIUS Attributes Reference Guide for attributes that are applicable in RADIUS L2TP tunnel accounting.