Looking at TCPView I can see over 25 svchost processes using TCP and UDP ports. If these svchost processes are the various services required by Windows, then why would so many be using the network?
According to wikipedia:
So, is expected that you have a lot of Windows processes running over a svhost.exe. Many of them just use TCP/IP ports(sockets) to inter-processes comunication over localhost. That's why you can see a lot of network traffic over svhost.exe.
Additionally you could also find which Windows Service is running over svhost. I run "tasklist /svc" command on my computer and it returned me the dependencies between svhost and some running Windows Services: