Remote extension - path of voice traffic?

I am looking at putting a single phone at a remote location. Just curious how the voice traffice will actually travel. The call comes into my cable connection into my asterisk box. It determines that it goes to the remote extension and goes back out my cable connection into the cable connection at the remote site. Someone answers that phone, now my question. Is Asterisk still in the picture? So the entire conversation is going into and out of my main office cable connection and then over to the remote phone? Browsing google it appears remote extensions are done all the time. I was just curious if the extra trips make the call any worse?

It depend on many conditions: whether either end is behind NAT, any special settings in sip.conf, etc. Search for voice path in voipinfo.org.