Comcast, outbound dropouts, questions - Resolved

Posts: 114 · Posted: Tue Apr 11, 2006 9:55 am Post subject:

Small update. The good news (for me at least) is the SB5120 did not stop responding to PingPlotter during another 6 second outage. This pretty much confirms it has something to do with some piece of Comcast hardware out there.

-Craig

Posts: 4 · New Forum Member Joined: Apr 11, 2006 Posts: 4

I am having the exact same problems and results with PingPlotter on both mine, and my girlfriends comcast/vonage set up, in different areas. So please keep posting new finds, as I am watching, and following along with the same results. This has been a headache for me for quite a while.

I find it interesting that the 73.x.x.x address just outside of your LAN is present in all my pingplotter traceroutes as well.

Posts: 114 · Posted: Tue Apr 11, 2006 6:54 pm Post subject:

CEaton2 wrote:

I am having the exact same problems and results with PingPlotter on both mine, and my girlfriends comcast/vonage set up, in different areas. So please keep posting new finds, as I am watching, and following along with the same results. This has been a headache for me for quite a while.

I find it interesting that the 73.x.x.x address just outside of your LAN is present in all my pingplotter traceroutes as well.

Glad what I'm going through may help you (and hopefully others). Where are you from? I'm curious how many have this 73.171.8.1 address as their first hop.

Today, Comcast sent out the same tech as last time. The work order said "3+ Trouble Call", but they still didn't send the "specialist". Although the guy who came was really nice and helpful, he didn't have the expertise nor equipment to resolve the issue.

The good news was the he called in and talked to someone at the Comcast office. She monitored the line, and while she was monitoring it, it went down. She said she didn't see anything when it happened. She then monitored something else ("the pole" or something) and noticed packet loss and some other condition that I can't pronounce. Whatever it was, the level was at -0.5 (which apparently isn't good). They needed a DRC, DRM, or some kind of machine to monitor the uplink, as most of the equipment the techs carry can only monitor downstream (as does "Mr Burns", a website they use).

The tech is going to put the paperwork on the desk of this "specialized" tech, who is supposed to call me tomorrow to set up an appointment (the 4th visit). He supposed to stay "for hours" until it's resolved. This was supposed to happen this past time, but Comcast sent out the same tech. The tech who came today did stay for over 2 hours, which they aren't supposed to do.

I'll update this as I have more information.

-Craig

Posts: 8 · New Forum Member Joined: Apr 08, 2006 Posts: 8

If you cable modem doesn't have good diagnostics you may be able to get some sense of cable plant issues if you have a Motorola Set-top box. Try this procedure:

1) Press the power button (on the box) to turn OFF
2) IMMEDIATELY press the 'Setup' button
(this should bring up the advanced diags screen)
3) Down arrow to 'Inband Status', press Right arrow

Check the SNR, AGL and error rates.

For example on mine I get:

SNR 35.4 db GOOD
AGL 55% GOOD
5 Second Error Count:
Uncorrectable: 000000 Correctable: 000000

Note: This reading is for the specific Channel you were on before you pressed the power off button...repeat this for a few random channels...or if you have a channel that shows some pixelization or quality drops.

A month ago my number looks like:

SNR ? db FAIR
AGL ?% POOR
5 Second Error Count:
Uncorrectable: incrementing+++ Correctable: incrementing+++

Posts: 8 · New Forum Member Joined: Apr 08, 2006 Posts: 8

outrun wrote:

Small update. The good news (for me at least) is the SB5120 did not stop responding to PingPlotter during another 6 second outage.
-Craig

OK, is there any way you can position your modem so you can physically see it...if so you want to see what the status lights are doing. So for example, on my Linksys CM there is a 'Cable' status light...when the modem is 'synched' it is solid green....when not syncing or trying to sync it is off and blinking, respectively.

If you have a similar LED then I'm guessing it's going to show that you are losing sync during your outages.

Posts: 114 · Posted: Wed Apr 12, 2006 9:28 am Post subject:

CyberCSI wrote:

outrun wrote:

Small update. The good news (for me at least) is the SB5120 did not stop responding to PingPlotter during another 6 second outage.
-Craig

OK, is there any way you can position your modem so you can physically see it...if so you want to see what the status lights are doing. So for example, on my Linksys CM there is a 'Cable' status light...when the modem is 'synched' it is solid green....when not syncing or trying to sync it is off and blinking, respectively.

If you have a similar LED then I'm guessing it's going to show that you are losing sync during your outages.

The SB5120 has lots of lights. Many orange, and one green (internet activity). The cable modem is not losing sync. All the orange lights stay lit. As I've stated before, the downstream does not drop out. The outages are only on the upstream. If the modem lost sync, it would lose both up and downstream, and a Vonage call would be disconnected. This does not happen. When I get an outage, the caller can't hear us, but we can hear them.

-Craig

Posts: 4 · New Forum Member Joined: Apr 11, 2006 Posts: 4

I just called comcast on behalf of my girlfriend, and myself, they found her connection dropping packets, but UDP and TCP, they are coming out this weekend, I'll see how that goes. They couldn't find anything wrong with my connect, I will have to get some evidence together on that front.

Posts: 114 · Posted: Thu Apr 13, 2006 12:16 pm Post subject:

Update.

Comcast sent a tech out in a truck this morning (this was unannounced nor scheduled). He set up shop in front of the drop on the side of our yard, ran a coax from the tap to his truck, and sat there.

My wife, wondering what was going on, called me, so I drove home (luckily I work 3 miles from home).

I talked to the guy, and he was monitoring the line (both up and downstream) with some new piece of equipment (DCM?). He also did a ping test to comcast.net.

He then was talking to his supervisor, who instructed him to go to speakeasy and do a bandwidth test. The guy couldn't figure it out, and while they were mucking with the web site, I had an outage. Unfortunately, the piece of equipment that was monitoring the line was on a different screen, and by the time he got it back to where it should have been, the line came back up. So he went back to just looking at it and doing a ping test from his laptop.

I didn't get any more outages during the time he stayed (another hour and a half). But, during his ping tests, he got a bunch of lost packets. He reported that in, and now they're going to send another guy to check out the lines and hardware in the neighborhood and figure out why he was getting lost packets.

So, the news is mixed. I didn't get a repro on the condition I'm getting, but he did lose lots of packets.

-Craig

Posts: 114 · Posted: Mon Apr 17, 2006 9:29 pm Post subject:

Update.

Apparently Comcast sent out another guy (unknowingly to me) to look at the lines. I had no idea anything had happened, until on Saturday morning, I noticed that PingPlotter showed no drop outs for 18 hours straight. This had never happened previously (longest was probably 4 hours).

Comcast called to confirm what they did helped (I was at Toys R Us with the family at the time). At that point in time, I thought everything was "resolved enough" (one drop in the past 24 hours), so I said that whatever was done, worked. So I asked what they did, and the woman on the phone said that according to the code attached to the ticket said a bad line out in the street was replaced (we have underground wiring for all utilities).

After monitoring it for the past two days, the dropouts have decreased ~75%. While it used to drop about 30 times a day, it's probably down to about 6-8. I'm going to call them this week and have them continue to look at it and find another bad line out there someplace. Only now, the dropouts are much more spreadout, so I don't know how long they're going to wait in their truck looking for more packet loss.

I'm happy that Comcast followed through and found (and resolved) a problem.

As always, I'll continue to update this thread.

-Craig

Posts: 114 · Posted: Thu Apr 20, 2006 10:45 am Post subject:

Small update.

We had an outage for about 2 minutes yesterday (around 5am). I'm not sure what happened, but since then, I haven't had one outage (30+ hours). I'm hoping that Comcast replaced another line, rerouted our connection to another port on a hub, etc.

If I get more drops, I'll be sure to contact them again.

-Craig

Update: 111 hours, no dropouts. I think my issue has been resolved by multiple Comcast efforts at replacing lines out in the street. Over and out.