We are using 3cx Small Business edition in two of our office locations. We are using SNOM phones. My company has 6 locations, and we would like to have 3cx in all locations. Our remote locations are connected to the main office via DSL site-to-site VPN tunnels. Each location's ISP provides an internet connection of 3 gb download 750 mb upload. We have some test phones deployed to test reliability and quality of VoIP over our VPN tunnels. Can anyone advise on what optimizations or other "best practices" I can make to our router configurations, to enhance the quality of conversations over our VPN tunnels between company sites? We are using a Sonicwall NSA2400 firewall/router with Enhanced OS. Calls outside the company are made through PSTN lines. I really appreciate advice. Thank you!