Atheling your comments are appreciated; can you expand on what you mean by ‘session to session persistance’?
I have 100% confidence in Asterisk as it is used by Australias 2nd largest ISP and apparently 16% of the global voip market. If I was to look at pure SIP proxy, where would you suggest i start looking?
For WAN balancing I originally considered a TP-LINK 4 wan router but ZS seemed to give more control.
BTW the comment ‘breaking new ground’ is too exciting to not pursue, would also learn a bucket load in the process. Prior to all this I knew nothing about linux programming, sometimes still feals like i do…
You want all traffic in a TCP session to use the same WAN link. My patch does that. However for things like a HTTPS session you also want subsequent TCP sessions to use the same WAN link otherwise the server you are going to will reject the traffic. That is what I meant by “session to session persistence”. However you don’t want that persistence to be forever either. Linux achieves this through a route cache. But the controls for aging things out of the route cache is, in my mind, arcane and very poorly documented.
My experience with Asterisk has been with either an old, slow computer or with a net5505 (new slow computer). Since all traffic goes through that one computer it is the first thing to be overloaded. Especially if you are doing any transcoding of the voice. A SIP proxy only handles the SIP exchange (low data rates) and the RTP (voice) data takes a more direct path. So generally that type of system scales better. That said, if you have enough horsepower in your Asterisk server you can achieve a lot more. I haven’t done enough research to recommend a specific SIP proxy system.