Vista - connection question

Hi,

I got two friends who lives here in the surrounding.

By both of them i enabled Upnp. When i video chat with them, everybody got
an Upnp connection, according to the connection tab in WLM

But recently the sound was terrible, (repeated and missing words), the video
freezes and we got disconnected.
A-ports shows me that there were three active connections for WML:
one to the Ip address from my chat friend
two to an unknown Ip address, probably the internet provider or so.

Even we got a direct connection, i got the message that the video quality
could be less, because of a
slow connection



I just want to know:

Should i be enough for video chat to have only one port connected to the
IP-address from my chat friend?

Does it means that when WLM is connected to the IP address of my chat friend
that is is a direct connection?
Thus no delay from a relay-server?

When the message appear that the video quality could be less, due to a slow
network connection,
does that means the connection is still via a relay-server?
(even i see wlm is connected with one port staight to my friends IP-address)
could it be something to do with the provider?

many thanks in advance,

heian