Juniper Networks M160 manual Packets Out

System Architecture Overview

JUNOS Internet software can efficiently support large numbers of interfaces and virtual circuits.

Management interface—Different levels of system management tools are provided, including the JUNOS command-line interface (CLI), the JUNOScript application programming interface, the craft interface, and SNMP.

Storage and change management—Configuration files, system images, and microcode can be held and maintained in primary and secondary storage systems, permitting local or remote upgrades.

Monitoring efficiency and flexibility—The router supports functions such as alarm handling and packet counting on every port, without degrading packet-forwarding performance.

The Routing Engine constructs and maintains one or more routing tables (see Figure 25). From the routing tables, the Routing Engine derives a table of active routes, called the forwarding table, which is then copied into the Packet Forwarding Engine. The design of the ASICs allow the forwarding table in the Packet Forwarding Engine to be updated without interrupting forwarding performance.

Figure 25: Control Packet Handling for Routing and Forwarding Table Updates

Forwarding table updates

Packets

in

Routing protocol

process

Routing Engine

Forwarding table

Packet Forwarding

Engines

Routing protocol packets from network

Packets

out

1240

Routing Engine Architecture 55