The VOIP data is probably not delivered over the internet for local calls. The calls probably come out of the cable network and hit a softswitch in the same cit

The VOIP data is probably not delivered over the internet for local calls. The calls probably come out of the cable network and hit a softswitch in the same city. For local calls, they probably have a TDM interface (T1s/DS3s etc) to the incumbent carrier and possibly other CLECs too.