I read above (and in other places) that you can only port numbers from mobile carriers (such as AT&T, T-mobile). I am using Vonage but, on a lark, I decided to check the Google Voice Porting dashboard page you provided and surprisingly it told me simply: "Congratulations.Your mobile number can be ported."

Consumers - SBG6580: VoIP Compatibility For more information about port forwarding, please refer to the following FAQ: 20816 - SBG6580: Port Forwarding Setup. NOTE: For information regarding the VoIP device, please contact the manufacturer. [H] Port Forwarding - Vonage + Router - TL Oct 27, 2011

Solved: VoIP phone not working with R8000 Router - NETGEAR

Motorola VT2542 - Vonage Port Forwarding Router Screenshot Router Screenshots for the Motorola VT2542 - Vonage. >Advanced>Port Forwarding IP QoS Port Forwarding IP Filters LAN Clients --> Web Filters Dynamic DNS Client Static Routing Dynamic Routing Remote Web Access Remote SSH Access Ethernet Switch Port Forwarding Allow Incoming Ping LAN IP: 192.168.15.2 DMZ Custom Port Forwarding Category Available Rules Games VPN Audio/Video Apps … Porting From Vonage To Google Voice

Your Vonage Online Account lets you make the most of your Vonage service with one convenient place to do all things Vonage: Block unwanted calls with Selective Call Block. Manage your Vonage service. Set up or modify calling features. Review call records and billing. Anytime, anywhere access from your computer, tablet or smartphone

One way audio on VoIP | Look at port forwarding on your Using Port Forwarding for VoIP to overcome NAT issues. Port forwarding, sometimes referred to as tunneling, is a method of opening a port or ports in a router or firewall to allow communication from a party outside the network. Port forwarding is the act of actually forwarding a network port from one network node to another.