This article briefly explains how different a Firmware Upgrade is from an OS Upgrade on Junos devices.
A Junos device is delivered with the Juniper Networks operating system (Junos OS) preinstalled. As new features and software fixes become available, you must upgrade your software to use them. On the other hand, the firmware is basically a set of instructions needed for devices to perform the tasks in a much efficient way than what they were normally designed for.
Unlike software (OS), the firmware is not created to perform specific functions on the hardware, rather it is used to get the optimal network performance, and to fix a vulnerability that could be caused over a period of time. More often than not, our devices are running multiple programs at a time, which will eventually degrade the system performance and will slow the pace of operations. The obvious solution that people consider in such cases is to replace the old, worn-out hardware with new parts. The other and the better way out is to update /upgrade the firmware that the system runs on. Firmware updates are far more cost-effective and simpler when compared to replacing the hardware.
Firmware updates help in upgrading the performance of hardware parts including Routing Engine, FPC, MIC, PIC, etc.
To verify OS and Firmware versions, refer to the technical documentation on the following commands:
show version
show system firmware
NOTE: Not all Junos versions support firmware packages and the software images/files for both OS and Firmware upgrade are different and serve different purposes. Hence, OS upgrades and Firmware upgrades are to be performed separately.
WARNING: A firmware upgrade is not recommended in a normal scenario. Please contact your JTAC Representative before upgrading.