I have peer to peer VOIP working over my LAN with SJphone ...no problem! I also run X-Lite for my normal VOIP and I have a Linksys PA2 ATA in my DMZ (as advised by my VOIP provider). To overcome performance problems, I'm seeking to understand how I can communicate directly (with IP addresses)between SIP nodes (Softphones and my ATA) over the internet.
I have discovered that my performance issues to date have been caused by multi hop routes to my provider(s). My current ISP / VOIP supplies are able to connect me within 4 hops and works fine most of the time even when the bit rate is well below 64k A simple Tracert revealed my whoes! Anybody able to advise?
ps Skype to Skype is usually awfull, Skype tp PSTN is worse ..I assume I'm using a supernode and not peer to peer.
VOIP optimization is something that generally requires access to settings that a residential Internet connection does not provide. But that doesn't mean there's nothing you can do.
First of all, though, what kind of "badness" are you experiencing? Choppy or lost connections? Poor voice quality? What kind of issues? The more detail you can give, the more we might be able to narrow down what you need to do.
One note, though: ISP's don't like VOIP. Unless they are selling it to you. It's entirely possible that the ISP is "managing" traffic such that this is happening. Your options at that point might be limited.