VoicePulse with lower-speed broadband cable connection...

I recently signed up for a VP account, and received my SPA-2002 last Thursday. I've had excellent results ("flawless", dare I say...) with them, especially compared to my BroadVoice line (which seems to be getting worse all the time). My internet connection is a Charter 3-Meg down/256k up connection.

So I brought my new ATA to my friend's house (they've got BroadVoice, too, and are having tons of problems) to let him try it out. I disconnected his BV adapter, and installed my VP ATA behind his router. And told him to try it for a day.

Well, I went to pick it up last night, and he told me they had reports of people they were talking to mentioning hearing their own voices echo back, and issues with dialing into my VP number when my friend told them to call him. He also had some issues with hearing "warbly" audio when he called home (my VP number) and his wife answered. His Charter cable connection is 384k down, and 128k up. I did have him set to use the G.711u codec, but VoicePulse advertises it at 64k, so there shouldn't have been an issue. BTW, there was no excessive internet usage by his PC during the phone testing (no Microsoft updates being downloaded, etc).

When I had the ATA on my network, I had assigned it a static IP, and also created a port-forwarding entry to forward ports 5060 and 5061 directly to the static IP of the Sipura (specifically mentioned on VP's FAQ pages in case you have issues). I didn't do that when I tested it on his network.

My question: Is it possible that the port-forwarding entry would make that much difference? Anyone else have similar issues that were cleared up by adding the port forward entry?

I'm likely going to let him test it again soon, and I'll be sure to do the port-forwarding and the static IP this time. I'll also turn on the bandwidth saver and bump the codec down a couple notches.

Anyone else successfully using VP with a 384/128k connection (or similar)?

Thanks in advance,
Chad

RE: VoicePulse with lower-speed broadband cable connection..

G.711 with only 128k upload is sketchy at best since it will basically kill your upstream connection when you're on a call.

RE: VoicePulse with lower-speed broadband cable connection..

G711 is 64k by itself but, with overhead it is more like 80 and I always allow about 100k for it. Try a compression codec. Someone correct me if i'm wrong but echo is related to latency. It appears that echo supression on the provider side works best at 32ms and 64 ms and after that it is dependent on whether the provider has decided to reduce the number of simultaneous calls on his equipment to supress echo with high latency. Your friend should ping the voicepulse server and the BV server to find out what his latency is. This could shed a lot of light on the echo problem. If it is over 64ms then my bet is Voicepulse's echo supression equipment. But, that is not the total story on the latency. If VP is using the net to transport the call after they receive it who knows what the latency will end up being. No way to really measure it. I like providers that have a tdm connection and keep the call in the public telephone network once they receive it. Voipwell is one of them.

RE: VoicePulse with lower-speed broadband cable connection..

Here is a chart that tells you the complete ethernet bandwidth taken by each codec: http://www.newport-networks.com/pages/voip-bandwidth-calculator.html . Sorry but it sounds like all your friends problems are codec related and involving him using an uncompressed codec on a high speed lite connection.

As for port forwarding, assuming it works at all with two-way audio, it shows all the ports are getting to the device fine and thus port-forwarding is already in effect. In fact your manually assigning ports 5060-5061 to your device are probably needless and even harmful if you install another VOIP device that uses those ports on your system. It seems clear STUN would allow you to NAT-traverse on its own since if you only fwd the SIP port 5060, that in itself is insufficient for VOIP to work since it also needs the RTP port range to be forwarded to the device. Since you didnt forward any RTP ports I can safely assume you wouldnt have needed to forward the SIP ports either. Assigning a static IP is needless here as well. DHCP works fine when STUN is the mechanism to traverse a NAT router.

ctylor - Man, that's an excellent bandwidth calculator. VERY detailed. One thing that surprised me was the amount of bandwidth reduction claimed when you have silence suppression enabled (which I believe is the default option on all these Sipura products. G.711u goes from 95.2k down to 47.6k with silence suppression enabled (and the note actually claims a 50% reduction with the silence suppression turned on).

Based on the tests using my friend's 384/128k connection, I would agree that the G.711u codec was a bit hefty based on the results he experienced. Unfortunately, when I left the ATA there for him to try for a day, he didn't call me at all to say he was having any problems. He waiting for me to ask, and of course that was right before I had planned to retrieve the ATA. Had he told me right after he was experiencing the issues, I would have changed the codec, and even tried the static IP/port forwarding thing.

Thanks for you input. I greatly appreciate it!

Chad

Beware of the Sipura's silence suppression feature! Try comparing your setup on an echo test like FWD's or Sipphone's (reachable if not already by adding a Sip Broker string to your Sipura dial plan) with and without silence suppresion enabled. Having it on can give you some unpleasant voice effects to portions of your sentences. Actually it is disabled by default on an unlocked Sipura--it may have arrived from VoicePulse with it already on but that was VP's setting and not Sipura's. Since you need burst speed capability all the way to the maximum specified by the codec (and choose your codec based on burst speed not average speed), to me personally I don't see the value of silence suppression when it will clip words in weird ways. I don't pay my ISP by the kilobyte, and I am not trying to run loads of concurrent phone calls that might butt up into my upload limit...so I actually suggest you disable it--but check with an echo test to confirm first if you feel it is important on your setup to have it.

Just saw this and wanted to let you know I've been using Voicepulse for almost a year with same Charter connection, and it's been flawless. I use the 32 kbps bandwidth saver speed with Voicepulse. Broadvoice didn't work well for me either.