How to integrate cloustack with physical network devices to replace system virtual machines

### The required feature described as a wish

CloudStack's network functions and management are usually implemented through System Virtual Machines (SVMs), especially network-related functions such as routing, NAT, VPN, DHCP, etc. How can we integrate with physical network devices to replace system virtual machines? Are there any relevant configuration cases?

The issue names no files, tests, or entry points. Start by clarifying which physical network devices and CloudStack network functions must be supported, then identify the relevant integration points and configuration examples. Done would include an agreed scope and documented configuration cases for replacing the specified system virtual machines.

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