Another Comcast user with dropped outgoing 'packets'

Posts: 3 · New Forum Member Joined: May 15, 2006 Posts: 3

Typical story - used Vonage for a year and noticed bad outgoing quality in past few months. Typically will talk for 30 seconds and then other party can't hear us for 1-10 seconds.
Have checked signal quality at various times and with/without other downloads occurring. Always getting 4.3/4.4 but, as below, packet discards can hit 10-20%.
Any suggestions? Have called Vonage and had them ? upgrade my Linksys RT31P2. My Motorola Surfboard SB5120 has latest firmware.
Wife is totally and completely fed up...if not good answers to this problem, any suggestions of other VOIP carriers? Planning to stay with Comcast as I hate DSL and no other cable options around here.
Thanks,
E

MOS Analysis From You TO Boston
MOS analysis chart
Media Quality
MOS
4.3 / 5.0
(Best with G.711 is 4.4)

Degradation Sources
Codec 0.57 79.5%
Latency 0.00 0.0%
Packet Discards 0.15 20.5%
Packet Loss 0.00 0.0%
Codec G.711 (PCM at 64kbps,
20ms RTP payload,
80kbps IP BW)
Round-Trip
Latency 148 ms
Packet Discards 0.8%
Packet Loss 0.0%
Loss Periods
Min: 20 ms
Avg: 20 ms
Max: 40 ms
Random Loss
Jitter
Min: 0 ms
Avg: 7 ms
Max: 32 ms
Signaling Quality
Post-Dial Delay 109 ms
Call Setup Time 109 ms
Media Delay 375 ms

MOS Analysis FROM Boston To You
MOS analysis chart
Media Quality
MOS
4.4 / 5.0
(Best with G.711 is 4.4)

Degradation Sources
Codec 0.58 100.0%
Latency 0.00 0.0%
Packet Discards 0.00 0.0%
Packet Loss 0.00 0.0%
Codec G.711 (PCM at 64kbps,
20ms RTP payload,
80kbps IP BW)
Round-Trip
Latency 148 ms
Packet Discards 0.0%
Packet Loss 0.0%
Loss Periods
Min: 0 ms
Avg: 0 ms
Max: 0 ms
No Loss
Jitter
Min: 4 ms
Avg: 6 ms
Max: 27 ms
Signaling Quality
Post-Pickup Delay 252 ms
Call Setup Time 256 ms
Media Delay 286 ms

Posts: 6 · New Forum Member Joined: May 15, 2006 Posts: 6

Same here on both accounts (outbound sound loss and wife getting i-rate). Frankly I have never had the problem before last Friday (05/12/06). On that day my Comcast service went down due to some service outage in the region. And before everyone jumps on the bandwagon with the test the line, router reboot, blah, blah, blah. It's been done and everytime it has been a Comcast issue. That is why I dropped their phone service and would love to drop internet if it wasn't the only high speed option in my neighborhood (new development less then 5 years old).

I need to follow up to determine what the cause of the outage was. I know they now offer levels of service 5MBits, 8MBits, etc. so I believe they have been upgrading their routing and controls to manage IP traffic. Personally I believe they are not blocking the service put perhaps causing it to be less reliable for certain host / port combinations (i.e. prioritizing non-Comcast VoIP lower then all other traffic). It would be virtually impossible for the Better Business Bureau or Attorney General to track this type of technology down without some type of whistle blower. It kinda like Internet Exploder and Windows. All other browsers don't seem to work very well cause Microsoft controls the OS. Well all other VoIP service pail in comparison when run on Comcast Networks.

Just my two cents. Will follow up on stats and additional info when I find out more. As an FYI Minneapolis / St. Paul region.

Linksys PAP2 (DMZ) -> USR5461 Maxg Router -> Motorola SB5120 Cable Modem

Stats:
MOS Analysis From You TO Boston
MOS 4.2 / 5.0
(Best with G.711 is 4.4)

Degradation Sources
Codec 0.57 76.7%
Latency 0.00 0.0%
Packet Discards 0.14 18.7%
Packet Loss 0.03 4.7%
Codec G.711 (PCM at 64kbps,
20ms RTP payload,
80kbps IP BW)
Round-Trip
Latency 146 ms
Packet Discards 0.5%
Packet Loss 0.1%
Loss Periods
Min: 20 ms
Avg: 20 ms
Max: 20 ms
Random Loss
Jitter
Min: 0 ms
Avg: 5 ms
Max: 23 ms
Signaling Quality
Post-Dial Delay 93 ms
Call Setup Time 109 ms
Media Delay 234 ms

Posts: 114 · Posted: Wed May 17, 2006 8:01 am Post subject:

It could be a matter of QoS settings or a bad line somewhere.

This may be useful:
vonage-forum.com/ftopic12747.html" rel="nofollow" target="_blank" class="postlink">Comcast, outbound dropouts, questions

Pingplotter ended up being the sole tool that drove Comcast to address the issue for me.

I suggest you ensure that no file sharing activities are running on any PC, disconnect all routers (including Vonage), and run PingPlotter for a day or two, routing to comcast.net. Look for outages, and report those to Comcast. That'll get the ball rolling if it's something to do with their network.

Good luck.

-Craig

Posts: 6 · New Forum Member Joined: May 15, 2006 Posts: 6

As an FYI, Comcast tech came to my house and said signal to my house was too strong!! He plugged my Cable Modem right into the box outside and same issue. So they are fixing some stuff on the box today but I'm not holding my breath.

Per eoren1's comments, I started running pingplotter against comcast.net and wholly cow, packet loss is pretty large. Usually 10% to 20% right out on the first hope. My guess is this is probably related to the high line power issue. But given this about the fifth hop jumps between 20% and 50% packet loss. My guess is the service outage last Friday was related to this and I'm going to use this information to follow-up with Comcast if the line issue to my house is not the final solution.

One other note. For the fun of it I pointed pingplotter against Vonage.com. Numbers were fairly analogous to comcast.net but when I picked up the phone and called my cell phone. The packet loss #'s skyrocketed to 60-70% range. Even some cases reporting ERR. May be cause of line power again but very curious.

I will follow-up when they have the tech come out and fix the line power problem. Then maybe, I will follow up with more info. BTW, what is an acceptible % packet loss. I know there will be someone say 0% cause I pay for it, but reality, what is that magic # (5, 10, ??).

Posts: 114 · Posted: Wed May 17, 2006 11:59 am Post subject:

It really should be 0% as far as PingPlotter is concerned.

-Craig

Posts: 6 · New Forum Member Joined: May 15, 2006 Posts: 6

I was just out there looking at some details on my cable modem and stumbled across this thread. Seems like they may know the issue but I have not been able to read the complete thread. Here is the link:

Broadband Forum -> Comcast HSI

I'm going to try out some of the suggestions and report back.

Posts: 7 · New Forum Member Joined: Nov 02, 2005 Posts: 7

interesting. we've been getting the same sort of issues here for the last few weeks as well, we've had comcast out to our place who said that our signal was VERY strong (too strong?!) - regardless, we get completely intermittent, yet unusable service. we're currently using a loaner modem from comcast to see if that's the issue, but there's been no change (both our original modem and the loaner are motorola surfboard 5100's)

Posts: 25 · Posted: Thu May 18, 2006 5:27 pm Post subject:

I use Comcast here in Michigan and seem to have no issues with packet loss that I can tell. I have never had anyone tell me of voice or connection problems.

To make it more interesting I have both Vonage and Sunrocket services and will use both at the same time with no drop in quality.

I have Comcasts basic internet service 6mb down and 300kb upstream.

Posts: 6 · New Forum Member Joined: May 15, 2006 Posts: 6

I need to do a little leg work but given what the Techs were telling me yesterday when they were at my house, many posters might be right that it's more local then central. By this I'm not talking about your house connection specifically but more like the neighborhood nodes. Also I have noticed when talking to my wife from work when she is on Vonage, that she can always hear me but I can't hear her which tells me it is more of a sending thing then receiving. I never had the problem until last Friday and it sounds like they extended our neighborhood node to a new development.

As many have stated it's probably because of expansion but not the typical view of more people using bandwidth but more related to power. Let me explain a little and I will elaborate more when I have more time.

When they add new connection points or head equipment, they typically have to crank up the power to support the new addition and what this most likely does is sets a # of cable modems into tailspins. If you look at your cable modems config you will see a figure related to Upstream and Downstream Power Levels. In this case your Downstream level drives your packet going out. This # is supposed to be between -12 and +12 dBmV. After Friday this # had skyrocketed to 21 dBmV on my cable modem but it still worked. A tech came out and made some adjustments to bring it back in range, but here are two reasons why it doesn't resolve the problem:

1) He said when the Downstream dBmV is above 12, it is like screaming on the line. Your through-put drops and the cable has impedance limitations that will prevent or slow this high of a signal. Now take my modem times the 200 other people on my node all screaming.

2) The second tech that came out adjusted my actual connection box and was explaining to me how the node I'm on has expanded. With all the new development, they just added another connection point. What made the comment more interesting was that he stated he now has the task of going back and rebalancing the complete neighborhood and adjusting every cable connection box so the signal is within spec for everyone.

So my bottom line conclusion is as follows: Some type of neighborhood upgrade or expansion --> more power on the line --> creating hundreds of screaming modems --> hence the periodic drop of outbound signal. An more over Joe or Jane web surfer doesn't see this because 98% of their communication is feeding them, with only the occasional ACK response back to sender.

Just a theory. I have put a call in to find out specifically why I was down for 1/2 hour on Friday and hence why my performance has been so bad using VoIP. 10 to 1 it was an expansion or a head adjustment to the neighborhood. I will probably start a thread on the Comcast site relating to this in hopes to snag some techs on my idea.

Posts: 114 · Posted: Fri May 19, 2006 8:15 am Post subject:

Interesting theory. But would a "screaming" downstread signal also cause the upstream to drop out? It appears that people are having upstream issues.

My downstream signal is -3 dBmV. My upstream is 43 dBmV. I do not have any drops (other than rare Comcast outages). My MOS is 4.4/4.4.

-Craig