So long as no users outside of your LAN are pulling a live video feed, the data draw should be trivial.
The maximum resolution for viewing DCS-931L live video through mydlink is 320 x 240. The throughput will depend on the image settings you configure through the web UI. Log into the DCS-931L web UI using a web browser on a PC on the same LAN as the camera and navigate to SETUP > Video > VIDEO PROFILE. The bit rate and frame rate will drive (in part) the data throughput. Since mydlink throttles down the throughput for remote connectivity, the maximum settings on this page will not be achievable for remote access via mydlink.