Dropped Calls

Posts: 1 · New Forum Member Joined: Apr 03, 2005 Posts: 1

Need help on debugging frequent dropped calls. Should I rush out and buy a new modem?

Based on search on the forum, it looks likely the likely cause is the cable modem. Thread: http://www.vonage-forum.com/ftopic2762.html+moto

Here is my setup:

Comcast Atlanta =>
DLink DCM 200 =>
Linksys WRT54G Firmware Version: v3.03.6 =>
Linksys RT31P2 =>
Leviton Distribution Panel with Line 1 BellSouth and Line 2 Vonage

Voip Speed Test:
Download 3,742,640 bps
Upload 372,192 bps
QOS 97%
RTT 65 ms
MaxPause 25 ms

Posts: 77 · Posted: Mon Apr 04, 2005 7:50 pm Post subject:

I have the same problem. I checked that well documented topics on this forum (http://www.vonage-forum.com/ftopic2067-0.html) but I did not fine any convenient solution. Hope you will.

Posts: 6 · New Forum Member Joined: Feb 09, 2005 Posts: 6

I too am having the same problem with dropped calls. Interestingly enough, I have Vonage telling me it's a Comcast problem with dropped packets and Comcast telling me they ran tests on my line and it comes up clean. I have found that if I receive a dropped call, then if I immediately try to redial, I receive a busy signal. I'm sure this has nothing to do with Comcast and I firmly believe it's a Vonage related problem. However, I can't seem to engage Vonage to help me debug this. If I call another number (ie. my cell phone), then immediately hang up once it starts ringing, I can then redial my original call and get re-connected. I know this is telling me something, but I don't know if this resets some type of switch or what.

I am a Comcast customer in the north Dallas area. I use a Motorola Surfboard SB4220 cable modem. I directly connect a Linksys RT31P2 router to this and have a Uniden PowerMax 5.9 Mhz telephone system. I have very little problems with my internet connection, so I'm very skeptical about directing the blame onto Comcast. However, I need to find a way to engage the right technical talent to diagnose my problem. I hate to give up the service as I think Voip is an emerging technology with a great price point. However, the random hangups are driving me back to a conventional phone.

Posts: 3198 · Posted: Tue Apr 05, 2005 7:37 am Post subject:

testyourvoip.com (detailed results) and moreso pingplotter.com (over 24 hours or so) is a good indication of packet loss.
just because you can browse the web quickly doesn't mean you aren't losing packets left and right.
on one hand, it's good there's apparently no issue between you and comcast, but that just means your problem is likely somewhere out there on the internet which becomes very difficult to remedy.
or it could be something else completely, but those are good places to start.

Posts: 6 · New Forum Member Joined: Feb 09, 2005 Posts: 6

I have run two tests on testyourvoip.com and have equal scores using both Boston and San Jose. The MOS analysis from me to San Jose was 4.2 (out of 5.0) and the MOS Analysis from San Jose to me was 3.8 (out of 5.0). My overall score was 3.8 which equated that to the equivalent of a cell phone call. At least with my cell phone, it doesn't randomly hang up. Does anyone know if a packet loss situation would cause a dropped call in the fashion where if I immediately redial the number I receive a busy signal? Interestingly that I can call another number (I always use my cell phone) and it will ring. Once I hear it ring, I hang up. Now I can redial my original number that I suffered the random hang up and the call will go through. Finally, is there some type of threshold value you can adjust to tolerate more or less packet loss? I can understand the concept of packet loss, but I still don't understand how this drives a dropped call. If I understand correctly, I have packet loss occurring all the time...it just requires a resend of the packet. I'm assuming once the packet loss hits some type of threshold, the Voip logic goes brain dead. Well, thanks for the response as I had not run the TestYourVoIP.com test. However, I've run the ping plotter test twice at over 8 hours each time. I sent the results to Vonage and that is when they told me Comcast had a packet loss problem. I contacted Comcast and they said they ran diagnostics and could not see a problem. As you can see, I'm the man in the middle who would like nothing better than to have the two companies collaborate to resolve my problem. Seems everyone is good about taking my money, but substandard in making sure my service works.

Posts: 227 · Vonage Forum Master Joined: Dec 10, 2004 Posts: 227

BBlackburn,
Unfortunately, the amount of packetloss that will destroy a Vonage connection is not always at the level of packetloss needed to get the attention of Comcast. I noticed you said you were using the SB4200. I don't recall when the Dallas area received their upgrades but between this forum and the dslreports site (comcast HSI forum) I know a lot of people experienced better performance by upgrading to the SB5100 modem. Just a thought.

Posts: 6 · New Forum Member Joined: Feb 09, 2005 Posts: 6

Well, my saga continues. I contacted Comcast and inquired about upgrading my cable modem from the Motorola SB4220 to the Motorola SB5100 as was suggested. Comcast said there was no need as the SB4220 would work fine with all the Comcast upgrades. Bummer.... I have also tried capturing PingPlotter data during my phone calls to see if the mysterious "packet loss" could be correlated to my dropped calls. Well, that has not worked at all as I have hard evidence where my calls dropped with less packet loss (I was running PingPlotter from Dallas to www.yahho.com) then when the calls worked fine with up to 40% packet loss. I sure wish I could get some help from Vonage. I have opened up several tickets and rarely get a reply. In the replies I do receive, it's the same basic stuff over and over again. The help desk folks are sympathetic and apologetic, but offer no constructive advice. I know Vonage is stringing me along as apparently their customer masses are working fine. As such, I can't readily admit defeat since so many other folks seem to get this solution to work. I have a couple of more things to experiment with, but admitedly I'm near the end of anything I can think of. I've spent more time and money than if I had simply stayed on my Comcast Digital Phone service. Too bad I can't charge Vonage for debugging their service. I suspect if the situation was reversed, Vonage would fire me as a supplier with such poor service. Oh well, nothing ventured, nothing gained. BTW...I use Voip at my office and have zero problems. Of course this is not a Vonage service, so I think their dependence on the internet to supply their infrastructure network will make it nearly impossible to sustain a quality service. If and when a Comcast starts to deliver a Voip solution at near the Vonage price point, I suspect many customers will flock to this. In the mean time, anyone got any more ideas on how I can isolate and debug my continued dropped calls blues?