Troubleshooting Voice Drop outs. Best Practices?

[Dave_N]

Hi,

I have recently cut over to voipo residential service. I am having voice drop outs in my service on nearly every call. Interestingly, calls to voice mail are okay. I haven't checked, but perhaps voice mail uses 80ms packets instead of 20ms packets?

This leads me to believe that my router (or my comcast service may not be up to snuff.)

So my network is as follows:

cable-->Motorola Sb5101 --> Netgear 824v2 -->linksys PAP2 (in DMZ)
\--> 4 wireless devices
\--> 2 wired devices

When I test for speed at Broadband test results I usually get about 5 Mbits down and 768Kbps - 1 Mbps. Doesn't seem to be a bandwidth issue. Similiarly when I ping I get decent response time so it doesn't seem to be a latency issue. This leads me to suspect that the router is dropping (or delaying) packets, but I don't know of a simple way to test this.

Since the PAP2 does a 10M link to the netgear, I should be able to insert a hub on this link and get a wireshark trace going. I have not done this yet.

Now, I know that MGCP endpoints support per call statistics, but most SIP devices do not. I called support last night and they said that they would enable extra logging but I am away from home right now so I can't place a call and replicate the issue.

Does anyone have any trouble shooting ideas?

Thanks,

Dave

[VOIPoTim]

Dave,

Has anyone mentioned having us fully handle your audio vs us redirecting it back out to Level3 media gateways?

Since you said voicemail works fine (audio is internal), it sounds like that could be a good solution for you.

[Dave_N]

Dave,

Has anyone mentioned having us fully handle your audio vs us redirecting it back out to Level3 media gateways?

Since you said voicemail works fine (audio is internal), it sounds like that could be a good solution for you.

Nope, I was trying to verify my end first.

I find it helpful, and often correct, to blame myself first.

Dave

[sr98user]

Try the following voip test sites

http://www.testyourvoip.com
http://voiptest.nuvio.com/

See what kind of results you get.

I took a quick look at the Netgear 824 manual. And it does not have any QOS. If VOIP packets are competing with any other traffic from your network, there will be quality issues.

[Dave_N]

Try the following voip test sites

http://www.testyourvoip.com
http://voiptest.nuvio.com/

See what kind of results you get.

I took a quick look at the Netgear 824 manual. And it does not have any QOS. If VOIP packets are competing with any other traffic from your network, there will be quality issues.

Yes, I was aware of the lack of qos. That was one reason I wanted to get hub on it and see what is happening.

By the way, do we know what a "good" router with qos is? I see the DL link 655 seems highly rated. It has "automated qos". I have no idea what that means. I would prefer a simple port priority scheme to give priority to the PAP2 media streams and the PAP2 sip signaling. Perhaps UDP priority would be enough.

[sr98user]

I don't have personal experience with DL-655. But others at dslreports have not said anything bad about it.

For some of the QOS routers, just turning it on will be enough. The RTP packets are marked with a IP precedence 5 and they are automatically given high priority. On some routers, you would have to give priority by MAC address. In this case all packets coming out of that MAC will be given highest priority. On more expensive routers, you can match packets based on your own criteria and give those packets specific bandwidth.

Many users have good results with getting a simple G router and flashing it with Tomato/DDWRT. Some of good ones mentioned are Trendnet 631, ASUS 520GL, etc.. You can also get a better Netgear model and try it out. See if it works well during upload/download. Make sure you are able to return it without restocking fee if you want to just try some from retail stores.

[quattrohead]

Try or borrow any other router. The Netgear FVS318 is a slow device in general for example, perhaps the 824 is not to special either. Even the $40 white wireless netgear router is significantly better than the 318.
I just switched to a Linksys running tomato and the whole network seems better.

[Dave_N]

And I spoke too soon. I am having drops with voice mail.

[Dave_N]

It ain't bandwidth.

[Dave_N]

Test my voip says it is latency and loss.