Upload video from local network 1GB/sec

How to upload video on my server which in my local network across 1gb/sec lan, no across the internet?

I can reach it with add to hos in windowst:
serverip domain
May it work automatically?
So that I can determine that the site does not work from the Internet, and at the same time, if it is, use a gigabit channel?

Why, when I uploaded video and delete it, transcoding still progress and as result save video in storage? And can I reboot server while transcoding process and it automatically resume after reboot?

Why uploaded video transcoding first 1080-240 instead 240-1080?