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Routing & Switching · Foundational

Junos OS

Juniper Networks' network operating system, built on a FreeBSD-derived kernel (or Linux in Junos OS Evolved) with a single code train across platforms.

Definition

Junos separates the control plane (Routing Engine) from the forwarding plane (Packet Forwarding Engine) and uses a candidate configuration with an explicit commit model. The CLI has operational mode (>) and configuration mode (#), with a hierarchical set-based configuration. Junos OS Evolved runs on a Linux kernel with independent process restarts.

Example

user@router> configure ; user@router# set system host-name R1 ; commit

Exam tip

Changes in Junos take effect only after commit; that is the core difference from Cisco IOS running-config.

Related terms