Qos; Connection Manager And Queue Manager; Ppp - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - SERVICE AVAILABILITY CONFIGURATION GUIDE 2010-10-08 Configuration Manual

JunosE 11.3.x Service Availability Configuration Guide

QoS

Connection Manager and Queue Manager

PPP

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policy attachment requests in bulk reduces the time to download all the attachments
to the newly active line module.
QoS configuration is maintained in each line module and these settings are mirrored to
the standby line module. During a stateful line module switchover, the QoS agent in the
line module restores the configuration in the newly active line module. The QoS agent
clients (such as IP and Ethernet) bind and register to the QoS agent before they replay
the interfaces for creating QoS attachments. The QoS agents ensure that the queues
are reestablished appropriately for the interfaces.
The queue manager resides on the SRP and the queue manager agents are present on
all the line modules. When the primary line module resets, the spare module takes over
the usage of the redundancy database. The queue manager identifies a connection based
on the queue ID, the connection manager uses the stream ID to recognize a connection,
the forwarding controller uses the stream ID, similar to the connection manager, to
determine a connection. For example, when slot 2 communicates with slot 1, the queue
manager identifies this connection as QID1. Similarly, when slot 3 communicates with
slot 2, this link is labelled as QID2.
The connection manager uses SID1 to denote the connection from any slot with slot 2
and SID2 to signify the link from any slot with slot 3. The slot 2 address is specified as
2a2, where '2' refers to the logical slot, 'a' indicates the active state of the slot, and '2'
represents the physical slot. When slot 0 takes over slot 2, the slot that is taken over is
identified as 2a0. On reception of the controller up event on the SRP module for the spare
line module, the queue manager initiates a request to the connection manager to create
a fresh connection for the address 2a0. The connection manager logically labels the
stream ID that refers to slot 2 to be down and creates a new stream ID to communicate
with slot 0. The forwarding controller database that possesses a mapping of the slot ID,
stream ID, and traffic class is updated accordingly to replace any streams that earlier
pointed to slot 2 to start referring to slot 0. The queue manager agent running on the line
modules handle the forwarding controller updates.
The PPP application on the line module contains the basic protocol, timers, and state
machines in a running state. All the dynamic session data collected from protocol
negotiations is present in the mirrored storage containers on the line module. For stateful
line module switchover, all the mirrored storage data is saved on the standby module,
replicating the session on the standby module. After the switchover takes place, the
application initialization process on the standby module reconstructs the mirrored data
and brings up the sessions to the established state (operational status is up). Some of
the sessions that are still in the process of being created (alternating between the up
and down operational states) are not retained during the switchover. This behavior of
not preserving sessions that are not established is similar to the characteristic followed
during unified ISSU, where sessions that are not completely created retry after the newly
configured primary line module is available.
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