Understanding Asterisk Networking Architecture

I’m trying to build out a small environment for asterisk, and have a couple questions.

I have a Netopia SDSL Router w/ QOS at the head of my network, it has 4 ethernet ports.

I was thinking of buying an 8 Port 10/100 POE Netgear Switch to power some Polycom 330 phones, and plugging this directly into the Netopia.

Question: Does the asterisk server actually carry any outbound traffic from a Polycom phone or does it just do the SIP setup for the call and the Polycoms communicate directly with our SIP Gateway provider? I’m guessing it makes sense to plug the asterisk server into the POE switch along with the Polycoms, but don’t know if this is really necessary.

I only have one ethernet interface in the asterisk, and no analog phone devices… Should I have more than one ethernet interface on asterisk?

I’ve looked for this data, but didn’t really find the info, or didn’t craft my search well… Anyway, thanks for reading!

asterisk stays in the media path so the traffic goes from phones to asterisk to SIP provider and vice versa.

based on what you have shared here, one ethernet card will be just fine.