Packet loss problem

elantraGT

Member
Dec 25, 2002
40
0
0
I have had this problem with my 4000k/384k high speed internet for 2-3 days now and it is making my VOIP phone service very choppy. After numerous emails, Comcast has finally acknowledged the problem, but say they can't help me any further until Tuesday morning when a technician will visit. Having an almost useless phone line is VERY inconvenient. I'm really hoping someone can give me a solution that I can use right now.

The following is a traceroute that I hope someone can look at and maybe provide a solution to my problem. I've already tried specifying a DNS (a few different ones actually), but it didn't help.

No matter how many times I do the traceroute, the results are the same.

C:\>tracert comcast.net

Tracing route to comcast.net [63.240.76.72]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms 192.168.0.1
2 7 ms 6 ms 7 ms 10.118.192.1
3 209 ms 7 ms 7 ms 172.30.33.81
4 7 ms 9 ms 10 ms 172.30.33.114
5 7 ms 7 ms 7 ms 172.30.33.238
6 8 ms 7 ms 8 ms 172.30.34.58
7 42 ms 7 ms 7 ms 68.47.160.50
8 15 ms 15 ms 16 ms 12.124.64.61
9 16 ms 20 ms 16 ms tbr1-p013701.attga.ip.att.net [12.123.21.98]
10 33 ms 30 ms 30 ms tbr2-cl1.wswdc.ip.att.net [12.122.10.69]
11 39 ms 37 ms 36 ms tbr2-cl1.n54ny.ip.att.net [12.122.10.53]
12 271 ms 35 ms 56 ms gbr1-p70.n54ny.ip.att.net [12.122.11.18]
13 331 ms 35 ms 36 ms gar1-p360.n54ny.ip.att.net [12.123.1.129]
14 331 ms 36 ms 36 ms mdf1-gsr12-2-pos-7-0.nyc3.attens.net [12.122.255
.162]
15 320 ms 38 ms 40 ms sccsbix12-1-4.attbi.com [63.240.64.46]
16 * * * Request timed out.
17 * * * Request timed out.
18 37 ms 37 ms 44 ms www.comcast.net [63.240.76.72]

Trace complete.

Any help would be appreciated. I can provide additional info if needed. I've not provided any specifics on my computer, because the issue for me is the VOIP. I am using a D-Link DI-524 router. However, comcast says the packet loss is occuring outside before the signal gets to my modem.
 

FlyingPenguin

Golden Member
Nov 1, 2000
1,793
0
0
Connect the VOIP hardware directly to the modem (be sure to power down the modem before switching cables - the modem always "locks" itself to the MAC address of the first device it "sees" when it's turned on).

If this problem occurs with the VOIP hardware connected directly to the modem, then there's absolutely nothing you can do (except power off and power on the modem, which I'm sure the Comcast tech already had you do at least once). The problem is on their end. Only thing you can check is house cable wiring. Make sure all fittings are tight and there's no water or corrosion at the outside splitter.

If a direct connect to the modem fixes it then connect the router back up, but connect ONLY the VOIP hardware to the router and nothing else. If the problem returns, it's related to your router.

If there's still no problem then connect your computers to the router ONE AT A TIME. It's possible one of them has a virus or a bad NIC and is causing packet loss on the LAN.

Hope this helps...
 

elantraGT

Member
Dec 25, 2002
40
0
0
Yup, along with a few others. Still no luck. Should I keep trying all the servers on the list I have, or is trying a few random ones enough?

I talked with tech support again and they are still seeing around a 20% packet loss. I have a technician appointment scheduled, but am still hoping to solve this sooner.

Keep the suggestions coming!
 

FlyingPenguin

Golden Member
Nov 1, 2000
1,793
0
0
Changing DNS servers is not going to solve the problem if it's packet loss.

90% of all packet loss problems with cable modems is a weak signal and it's usually due to having the modem on a weak tap. The modem should be on it's own home-run cable straight to the outside box (not sharing a cable with anything else). The installers should have put a special splitter in the outside box that sends a stronger signal to the modem than any of the other outlets (your normal splitter evenly splits the signal between all outlets).

If you want to confirm that it's a weak signal problem, temporarily wire the outside connections so that the cable is fed DIRECTLY to the modem, with NO SPLITTERS in line. You'll need to go to Radio Shack and get a "F Fitting Barrel Adapter) that will let you connect the incoming cable to the line running to the modem.

This will hit the modem with the strongest signal possible. If you're still getting packet loss then the problem is on the pole, or the cable leading to the house, or the cable going to the modem is bad.

I live on a 20 acre ranch with a 600 foot cable run to the street and we have 5 TVs in the house plus the cable modem (and using 2 digital converter boxes which also require a LOT of signal). No matter what they did they couldn't get enough signal to make all the boxes and the modem happy, so they had to install a special line amplifier in the outside box (one that's compatible with cable modems because your standard ones are not) and that solved all my problems.
 

elantraGT

Member
Dec 25, 2002
40
0
0
Penguin, did your problem exist from the time they hooked up your service, or did it occur later? I've had a good month or so of service prior to the problem occuring this week. When I checked inside the conncection box yesterday, the connections were all tight and dry, but there were 2 or 3 splitters in there and Comcast didn't provide a dedicated line to the modem. They just left things as they already were.
 

Big Lar

Diamond Member
Oct 16, 1999
6,330
0
76
Sounds like 1 of 2 things/ either you had a splitter go bad, or... maybe they put a filter/tap on the line.
 

FlyingPenguin

Golden Member
Nov 1, 2000
1,793
0
0
My service was fine, but then degraded over time. I would have days where I would get major packet loss for a 1/2 hour at a time or more. Usually late at night.

If you have minimal signal to start with, it doesn't take much to lose some signal. A drop at the pole due to corrosion would to it.

You also should DEFINATELY not have multiple splitters. That's inefficient.

Comcast usually uses the existing wiring until you have a problem, then they usually install a home run. It's time to excalate and have them come out and check it. They can easily put a meter on the cable that's going to the modem and read the signal strength. If it's less than optimal they need to put in a home run and install a proper splitter at the outside box.
 

elantraGT

Member
Dec 25, 2002
40
0
0
Comcast was out here today. The technician checked the signal at my house and at the pole right out in front of my house. He said my line noise was almost non-existent and that the problem has to be handled by a different group of techs.

I asked some questions while the tech was here and this is what I got:

The node is a few miles from me and I'm at the tail end of one of the branches.
My line noise was -55.
Because the line noise was negligible, changing the wiring setup to the house or putting in a line amplifier would not make any difference.

For what it's worth, my speed has picked back up (after reaching a record low for the weekend of 147K this morning) to around 1-2MB download speed. At least my VoicePulse is usable now. :)

Thanks for the continued help.
 

elantraGT

Member
Dec 25, 2002
40
0
0
Nobody knows anything still. Hopefully I am getting escalated to tier 2.5 and a line specialist. One thing that is constant is those 2 hops timing out (see my original post). Is this an important clue to my problem or do I need to be looking elsewhere?
 

ThePiston

Senior member
Nov 14, 2004
861
0
76
comcast has been bad for me too lately... 10-30% packet loss for a week... perked up yesterday
 

BadThad

Lifer
Feb 22, 2000
12,099
47
91
12 271 ms 35 ms 56 ms gbr1-p70.n54ny.ip.att.net [12.122.11.18]
13 331 ms 35 ms 36 ms gar1-p360.n54ny.ip.att.net [12.123.1.129]
14 331 ms 36 ms 36 ms mdf1-gsr12-2-pos-7-0.nyc3.attens.net [12.122.255
.162]
15 320 ms 38 ms 40 ms sccsbix12-1-4.attbi.com [63.240.64.46]
16 * * * Request timed out.
17 * * * Request timed out.
18 37 ms 37 ms 44 ms www.comcast.net [63.240.76.72]

Sure looks to me like the problem is beyond your control. Hops 16 and 17 turn to crap. I've encountered this during my gaming experience. You ping starts fluxing at ATT's network at node 12, notice the 271ms ping spike.

When I've had this problem in the past, I had to keep a daily log of my traces and submit them to my ISP. They contacted offender, which also happened to be ATT, who sent techs out to repair a bad router on THEIR network. After about two weeks, my ping returned to 50 ms (was 200-300ms when bad) at the server I was playing on nightly.

Keep a log of trace routes and good luck!
 

JDCentral

Senior member
Jul 14, 2004
372
0
0
It may also be that Comcast is just building a ton of new nodes on their network... I know that our network was AWESOME at first (b/c we were the only ones on the whole node!), but then degraded SIGNIFICANTLY over the next 6 months.

EDIT: No packet loss problems, though!
 

gistech1978

Diamond Member
Aug 30, 2002
5,047
0
0
Originally posted by: elantraGT
Funny how that happened for you when it did for me also...I'm sure it was just a coincidence. lol

im starting to think not.
im having the exact same problems.