I have an NVR, but you may have a similar screen for your DVR. My LAN1 is the outgoing bandwidth.
You have in the DVR the ability to set bitrate for each camera in both MAIN and SUB. This is important as the upstream bandwidth will change based on the stream(s) selected.
If you switch can be managed, you can enable the port miroring function .
Eg, Your DVR is on port 12, you put your PC on port 2, then setup that you want to miror 12 on port 2. Then on your PC you can use Windows bandwidth console or launch a graphical bandwidth utility to see Uploads and Dowload from the servers (here mostly video uploads to remote client, as incoming are mostly TCP Ack so very low)
in Some DVRs (and NVRs) you can customize precisely the outcoming streams to adapt to your xdsl or 3G/4G local reality (small res, low fps, strong compression..)