It looks like all the basic components are already in home assistant however there is a lot of extra config work involved just to get something as common as the current bandwidth.
You need an SNMP sensor and then a template sensor, and if you want meaningful averages an automation on top. Example Config
It would be nice if we had a nicely wrapped sensor that took care of this making it only a few lines more than the SNMP sensor including the UNIT and AVERAGE functions as config parameters.