JUNOS Software Overview
The JUNOS software runs on the router's Routing Engine. It consists of software processes that support Internet routing protocols, control the router's interfaces and the router chassis itself, and allow router system management. All these processes run on top of a kernel that enables communication among all the processes and has a direct link to the Packet Forwarding Engine software. You use the JUNOS software to configure the routing protocols that should run on the router and to configure properties of the router's interfaces. Afterward, you use the JUNOS software to monitor the router and to troubleshoot protocol and network connectivity problems. For more information about monitoring the router and troubleshooting problems, see the JUNOS Internet Software Network and Services Interfaces Command Reference and the JUNOS Internet Software Protocols, Class of Service, Chassis, and Management Command Reference.