Figure 5: Nonstop Active Routing Switchover Preparation Process - Juniper EX9200 Features Manual

High Availability Feature Guide for EX9200 Switches
36
Figure 5 on page 36 shows the system architecture of nonstop active routing and the
process a routing (or switching) platform follows to prepare for a switchover.

Figure 5: Nonstop Active Routing Switchover Preparation Process

Routing Engine 0 (master)
Routing protocol process (rpd)
and other processes
Chassis process (chassisd)
4
8 2 2
Kernel
1
3
The switchover preparation process for NSR follows these steps:
The master Routing Engine starts.
1.
The routing (or switching) platform processes on the master Routing Engine (such
2.
as the chassis process [chassisd] and the routing protocol process [rpd]) start.
The Packet Forwarding Engine starts and connects to the master Routing Engine.
3.
All state information is updated in the system.
4.
The backup Routing Engine starts, including the chassis process (chassisd) and the
5.
routing protocol process (rpd).
The system determines whether graceful Routing Engine switchover and nonstop
6.
active routing have been enabled.
The kernel synchronization process (ksyncd) synchronizes the backup Routing Engine
7.
with the master Routing Engine.
For supported protocols, state information is updated directly between the routing
8.
protocol processes on the master and backup Routing Engines.
Figure 6 on page 37 shows the effects of a switchover on the routing platform.
Routing Engine 1 (backup)
Chassis process (chassisd)
6
Kernel synchronization
process (ksyncd)
7
7 8
3
Packet Forwarding Engine
Routing protocol process (rpd)
5 5
5
Kernel 5
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