NetGear Interferes with VoIP Phone

I had a NetGear WNR3500 and a Linksys SPA942 IP Phone.  The phone worked fine...for about 10 minutes...but when then go silent.  Went through various gyrations with swapping equipment (routers, switches, etc.) in and out until the problem was pinpointed to the Netgear router.

Turns out, the problem is the ports on the router will chop off the VoIP activity after 10 minutes unless you configure port forwarding.

Check with your provider for the ports your specific phone model uses and then configure your port forwarding.

Here is how I solved the problem in NetGear
1. Setup a static IP for the phone in NetGear, under LAN Setup, Address Reservation.
2. Setup a TCP/UDP for the first port range, pointing to the IP of the VoIP phone.
3. Setup a TCP/UDP for the second port range, pointing to the IP of the VoIP phone.
4. Restarted the router.
5. Restarted the phone.