Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?


Storage Media and Routing Engines


The Routing Engine and Packet Forwarding Engine (PFE) are the two primary components of Juniper Networks platforms. Junos OS Evolved software is installed on the routing engine and it is stored in storage media.

Routing Engines and Storage Media

Juniper Networks routing platforms are made up of two basic routing components:

  • Routing Engine—The Routing Engine controls the routing updates and system management.

  • Packet Forwarding Engine (PFE)—The Packet Forwarding Engine performs Layer 2 and Layer 3 packet switching, route lookups, and packet forwarding.

From a system administration perspective, you install the software onto the Routing Engine and during the installation, the appropriate software is forwarded to other components as necessary. Routing Engines include two solid-state drives that store Junos OS Evolved.

Storage Media

Junos OS Evolved devices use the following storage media components:

  • Solid-state drives—Junos OS Evolved devices use two SATA based solid-state drives (SSDs) as the primary storage devices. The two SSDs are designated as primary and secondary. The primary SSD acts as the default boot device.
  • Emergency boot device—You can use an external USB drive as the emergency boot device for Junos OS Evolved devices. For more information on creating an emergency boot device, see Boot Junos OS Evolved by Using a Bootable USB Drive