Junos Architecture (Processes)
Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/architecture-processes
Lab: https://networkdirection.net/labsandquizzes/labs/jncia-labs/junos-architecture-processes
Notes
Operating systems can be classified as modular, or monolithic.
Monolithic operating systems have the kernel manage all functions. This is fast, but unfortunately, one area of code can affect another area of code.
Modular operating systems split functions into completely separate and independent processes. If there’s a fault in one process, it will not affect another.
Junos is a modular operating system.
Common processes include:
- chassisd – Starts up PFE’s, interfaces, and related hardware
- dcd – Manages devices
- mgd – Device management (SSH, web, CLI, etc)
- rpd – Manages routing protocols (a multithreaded process)
- snmpd – responds to SNMP polling, sends SNMP trap messages
Command Summary
| Command | Mode | Description |
| show log dcd | Operational | Troubleshoot the device control daemon |
| show system processes extensive | Operational | Shows a full list of processes |
| restart web-management | Operational | Restart the web management daemon |
Additional References
What is a monolithic operating system
Using Cows to Explain the Differences of the Cisco Operating Systems
https://medium.com/@Meela349588204/using-cows-to-explain-the-differences-of-the-cisco-operating-systems-876d14145827
Junos OS Routing Engine Components and Processes
https://www.juniper.net/documentation/en_US/junos/topics/concept/junos-software-components-and-processes.html
Junos OS Routing Processes
https://www.juniper.net/documentation/en_US/junos/topics/reference/general/junos-os-processes.html