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JunosE 11.3.x Service Availability Configuration Guide
Policy Statistics
Related
Documentation
Performance Impact and Scalability Considerations
94
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)
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.
Application Support for Stateful Line Module Switchover on page 79
Some performance impact occurs when a new secondary line module is provisioned or
inserted, with the primary module containing the maximum number of tunneled PPP
sessions. The synchronization of data occupies some backplane bandwidth, which might
slightly impact the call setup rate during the time the secondary module is plugged in to
the slot.
The maximum number of ingress or egress policy statistic entries that can be configured
is 512,000 entries. Each statistic entry is a combination of an 8-byte packet counter and
an 8-byte octet counter. The configuration of this maximum number of policy statistics
causes the collection of 8 MB of data (512,000 entries * 16 bytes = 8,192,000 bytes).
TIP: Because the collection of statistics and mirroring of data is
processor-intensive, we recommend that you do not exceed 2 MB of statistics
data when you configure stateful line module switchover. The preservation
of 2 MB of statistical information maps to an average of 8 statistics entries
per subscriber for a fully scaled subscriber environment (16,000 subscribers
* 8 statistics per subscriber * 16 bytes per entry = 2,048,000 bytes). You can
maintain the limit on 2MB of statistics by reducing the number of subscribers
and increasing the statistics per subscriber, or by increasing the number of
subscribers and reducing the statistics per subscriber.
Although the applications that support stateful line module switchover are enhanced in
their infrastructure and design capabilities, performance of the line modules is not
Copyright © 2010, Juniper Networks, Inc.
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