What is ISP communicating?

I use DODO dialup. Sometimes when my XP is started and gets connected I can observe that there is some communication going (TCP connection to 123-2-2-208.core.dodo.com.au:http). I wonder what data is transferred during this. What DODO ISP communicates even if the explorer isn't on yet. Windows would rather connect to Microsoft update if anything. So what is really going on there?