Whats the best way to route both? I have read the wiki on the ECMP load balancing (I don’t want to load balance, just route all voip traffic to SIP trunk and route data through the cable modem), also read the Load Balancing over Multiple Gateways wiki. Any recommendations from someone who has done it?
You need to create a rule for marking of specific routing traffic. Here i have used protocol udp and sip port 5060 for understanding. you can change it accordingly.
you have to keep RTP in mind as that is the real reason to send traffic over an alternative WAN - to dedicate a connection to improve voice quality.
with that in mind you may have to add a fourth line to that config to include UDP ranges of 10000:20000, or whatever your provider’s RTP port range happens to be.