Here we have replaced the contents of the host (which was captured in variable $2) and only used $1 and $3 and inserted the desired hostname. The SBC will generate the new outbound SIP request with the new Diversion header value.
Can Virtual Machines Introduce Jitter?
Yes a virtual machine can introduce jitter into the audio stream. At the same rate other factors such as the network are the typical causes of jitter.
The reason for this is virtualization software is typically not optimized for the real time needs of voice over IP. As well the virtualization software introduces an abstraction layer on top of the hardware. This means the hardware is being emulated to your guest OS. Your guest OS does not have direct access to the real hardware it is running on. It always has to go through the abstraction layer to use the hard disk/CPU/memory and other resources.
The best defense against this is to ensure there is enough resources allocated to each VM. In addition to this ensure you never over allocate any resources on the host OS. As well it is always a good idea to keep your virtualization software up to date.