Junos Architecture (Processes)

Table Of Contents

Notes
Command Summary
Additional References

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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

Junos OS Routing Engine Components and Processes

Junos OS Routing Processes