No voice on other end of call

[jesoma]

It seems about every week I have to reboot either the VOIPO router or like today my cable modem to fix a problem. The problem is either the caller cannot hear me or I can't hear the caller. I have ports UDP: 5004-65000 forwarded. Anything I should change or look at?

Jeff

[tritch]

The basics.....

1) assign a static IP to the ATA in the router
2) verify UDP ports 5004-65000 are forwarded to the ATA's static IP
3) verify SIP ALG is turned off in the router (if applicable)

If these are correctly set and you are still having one-way audio, can you try putting the ATA ahead of the router just as temporary measure for testing? If the problem still persists in this scenario, contact Support. If the problem goes away, you likely have port blocking or NAT issue still going on in your router.

[Russell]

The basics.....

1) assign a static IP to the ATA in the router
2) verify UDP ports 5004-65000 are forwarded to the ATA's static IP
3) verify SIP ALG is turned off in the router (if applicable)

If these are correctly set and you are still having one-way audio, can you try putting the ATA ahead of the router just as temporary measure for testing? If the problem still persists in this scenario, contact Support. If the problem goes away, you likely have port blocking or NAT issue still going on in your router.

Nicely summarized.

[stevech]

why is it that I've not had to do port forward/triggering on any of the routers I've owned, for Linksys and GS ATAs, but doing so is the standard guess as to problem correction?

(ATA on LAN side of router)

[sr98user]

The main reason is there are different kinds of NAT

http://en.wikipedia.org/wiki/Network_address_translation

Firewall and SIP ALG (SIP packet re-write) implementation differ for each router. That might cause problems on some routers.

Since VOIPo doesn't proxy the audio stream and traffic goes directly to the upstream carrier, the routers need to allow traffic from upstream carriers. Some routers don't do that.

[stevech]

Since VOIPo doesn't proxy the audio stream and traffic goes directly to the upstream carrier, the routers need to allow traffic from upstream carriers. Some routers don't do that. Tutorial for me...
Is it the case that the VoIP bearer traffic (audio) is a stream of UDP (RTSP) packets from the ATA through the router to the carrier's host - and the return is a likewise stream of UDP packets. And some routers figure out that the return stream mates with the outbound stream and forwards to the correct private LAN IP address? This is somehow done by remembering the port and remote host in the router for outbound, then when packets come back from that same host, they go to the LAN IP that is doing the outbound? Or something like that? Is there an IETF/RFC for this scheme that one could confirm before buying a router (to see if they claim to do so)?

I've owned several Linksys routers and this Cradlepoint MBR900 and none have needed explicit port forwarding for VoIP, perhaps due to the above.

(end of lesson 1)

[voipinit]

My Linksys router will break VOIP if I forward the ports for VOIP traffic, it shouldn't but typical crappy firmware from Linksys. Fortunately, placing the ATA in DMZ allows it to function correctly but does require STUN setup on the ATA and UPnP enabled on the router. It's a WRT54GX2 in case you are wondering.