What is "Guest Authentication (vgauth)" and "Common Agent (caf)"?

[nassaucounty]

What do these (vgauth and caf) do exactly?  We recently upgraded to ESXi 6.0 and when I update VMware Tools on a Linux VM I am asked "Do you want to enable Guest Authentication (vgauth)? Enabling vgauth is needed if you want to enable Common Agent (caf). [yes]"  I don't recall being asked this in the past. Not being sure what this is I answered no and the install completed successfully.  By not installing what functionality will I be missing?  I've Googled for information but can find no explanation of what the "Common Agent" is or does.

Thanks

[nassaucounty]

I found this but it really does not tell me anything (what functionality will I be missing if I don't install it?):

Common Agent Framework: Common Agent Framework (CAF) provides the basic services necessary to simplify secure and efficient management of agents inside the guest virtual machines.

[ykzhang]

Multiple VMware management solutions (e.g. vCM, Hyperic, Log Insight) require  installation of in-guest agents.The Common Agent Framework attempts to provide a common framework to unify and simplify the management of various types of agents, and these agents would be referred to as Common Agent.

Those VMware solutions are working on distinct administrative domains from the guest. VGAuth provides a way to authorize those solutions users' behaviors(install agent for example) within guest.

[PatrickSteranka]

So if I'm a developer running VMWare Workstation Pro and just installing VMs for my personal use and not interacting with the other VMWare products, I can safely run without Guest Authentication and Common Agent.  Correct?  I believe this is what I just got out of the previous answer.