Helping people with computers... one answer at a time.
If automatic time update is turned on, then it may simply be svchost periodically attempting to access the internet.
Why does svchost access the internet?
This manifests a couple of ways: your firewall warns you that svchost.exe is attempting to the internet, or it attempts to dial your internet provider.
It's probably simple.
You probably have automatic time updates turned on. That runs as a svchost hosted process (What is SVCHOST?), and periodically attempts to connect to an internet service to set you clock for you. You can turn that off by right clicking the clock in your task bar, selecting Adjust Date/Time, and clicking on the Internet Time tab.