I think most a cameras these days have a "digital" CCD chip instead of a tube for capturing images. Therefore nearly all are digital. Speaking only of CCTV security cameras, my understanding is that the camera usually has a BNC or analog output. There are some cameras on the bottom end of the scale that have an RJ-45 (some even RJ-11) that work in a dedicated fashion within a branded system (monitor, mux, DVR set up)
. There are ones that have a RJ-45 connector and include their own web server.
Some of those support PoE. Those are more expensive by more than double than a camera with just the BNC analog output. If you have an analog BNC camera output you can purchase an encoder to turn the analog video into a "stream" on a IP network
I don't know what other the digital versus analog you might be speaking of.