# Preservation of Statistics During Stateful Line Module Switchover

Statistical details associated with PPP and policy manager applications are retained across a stateful line module switchover. All other counters for settings and parameters connected with other applications running on the router are reset to zero after the switchover occurs to the new primary module. The following sections describe details on the statistics polling process and the attributes that are maintained after a stateful line module switchover:

## PPP Accounting Statistics

For each PPP subscriber, accounting statistics are polled and collected every 10 minutes. These statistics are synchronized with the secondary line module. The statistical details collected just before the switchover represent the baseline for statistics on the newly configured primary module. At a maximum, statistics that accumulate for about 10 minutes might be lost and not synchronized with the new primary module. This scenario occurs when polling was to happen and the primary module switched over to the secondary module, just before polling commenced. The JunosE software begins the collection of accounting statistics for terminated PPP sessions following, but not including, authentication acknowledgement from the E120 and E320 router. The acknowledgment is either a CHAP success or PAP acknowledgement packet. The following PPP statistics are retained across the stateful line module switchover:

- Number of IPv4 octets received from the interface (Acct-Input-Octets, RADIUS attribute 42)
- Number of IPv4 octets transmitted to the interface (Acct-Output-Octets, RADIUS attribute 43)
- Number of IPv4 packets received from the interface (Acct-Input-Packets, RADIUS attribute 47)
- Number of IPv4 packets transmitted to the interface (Acct-Output-Packets, RADIUS attribute 48)
- Number of IPv6 octets received from the interface (Ipv6-Acct-Input-Octets, RADIUS attribute 26-151)
- Number of IPv6 octets transmitted to the interface (Ipv6-Acct-Output-Octets, RADIUS attribute 26-152)
- Number of IPv6 packets received from the interface (Ipv6-Acct-Input-Packets, RADIUS attribute 26-153)
- Number of IPv6 packets transmitted to the interface (Ipv6-Acct-Output-Packets, RADIUS attribute 26-154)

## Policy Statistics

Similar to PPP accounting statistics, aggregates of policy parameters are polled and collected every 10 minutes. These statistics are synchronized with the secondary line module. The statistical details collected just before the switchover represent the baseline for statistics on the newly configured primary module. At a maximum, statistics that accumulate for about 10 minutes might be lost and not synchronized with the new primary module. This scenario occurs when polling was to happen and the primary module switched over to the secondary module, just before polling commenced. The counters for all policy-managed packets and octets that are configured for simple classifier, rate-limit, and parent-group actions are retained across stateful line module switchover.

#### Related Documentation

- Application Support for Stateful Line Module Switchover