Appendix A. Under the Hood

One of the most frustrating things about networking technology is that oftentimes operators are caged into a box called the command-line interface (CLI). Anything behind the curtain doesn’t exist and isn’t supported. Unfortunately, I can’t change the not-supported part, but I can at least show you what’s behind the curtains and how it works.

Any additional information you’re able to pull from a piece of technology ultimately makes your network better, whether it’s better network management, graphing, or troubleshooting.

Big Scary Disclaimer

Everything I’m about to show you in this chapter isn’t supported by Juniper Networks or the Juniper Technical Assistance Center (JTAC). Don’t use these commands in production. Use them at your own risk. Changing any values at a low level will cause instability in the network because the changes will not be synchronized with the control plane.

With that out of the way, let’s get on with having some fun!

The Broadcom Shell

The Broadcom shell, owned and maintained by Broadcom, is the standard CLI that you can use to directly access the Broadcom chipsets. It is a simple tool that you can put to work gathering additional debugging information from the system.


Messing around with the Broadcom shell is really powerful but at the same time really dangerous to production systems. Many of the commands are simply not documented for the average user. If you want the full documentation of the commands ...

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