Routing Engine And Packet Forwarding Engine; Kernel And Microkernel; Junos Software Processes - Juniper J2300 Getting Started Manual

J2300, J4300, and J6300 Services Router Getting Started Guide
This section contains the following topics:

Routing Engine and Packet Forwarding Engine

A Services Router has two primary software processing components:
For information about Routing Engine hardware, see "J2300 Routing Engine"
on page 12 or "J4300 and J6300 Routing Engine" on page 26.

Kernel and Microkernel

The Routing Engine kernel provides the underlying infrastructure for all
JUNOS software processes by doing the following:
The microkernel contains device drivers and processes that the Packet Forwarding
Engine uses to govern the flow of packets through the Services Router.

JUNOS Software Processes

The JUNOS software running on the Routing Engine and Packet
Forwarding Engine consists of multiple processes that are responsible
for individual Services Router functions.
The separation of functions provides operational stability, because each
process accesses its own protected memory space. In addition, because
each process is a separate software package, you can selectively upgrade
all or part of the JUNOS software, for added flexibility.
Table 14 describes the primary JUNOS software processes.
34
Software Overview
Routing Engine and Packet Forwarding Engine on page 34
Kernel and Microkernel on page 34
JUNOS Software Processes on page 34
User Interfaces on page 35
Routing Engine—Creates and maintains the routing tables that determine how
packets are routed through the network.
Packet Forwarding Engine—Processes packets; applies filters, routing policies,
and other features; and forwards packets to the next hop along the route
to their final destination.
Linking the routing tables maintained by the routing protocol process with the
forwarding table maintained by the Routing Engine
Coordinating communication with the Packet Forwarding Engine, primarily
by synchronizing the Packet Forwarding Engine's forwarding table with the
master forwarding table maintained by the Routing Engine