Hello anyone,
I'm just trying to find what the term is called that referes to this way of writing an ip address:

192.168.100.0/12

i don't even know if i wrote that right...but what is it called when it is written with the "/12" part?? i'm trying to learn it, but i can't even look it up on any sites cause i have no idea what it's called or how to refer to it.

maybe if someone could even explain it a bit.

thanks!
-jes