What is causing this? V. Huge packet loss

[Passafire]

I usually get around 20-30mbps down on any given day from Comcast. The last 3 days, i've been getting HUGE dips and packet loss, averaging around 3mbps.

Comcast insists there is nothing wrong and it's my modem, and wanted me to rent theirs or replace mine. Since it's a brand new modem, just to prove them wrong, I just went and exchanged it for a brand new one an hour ago.

Same issue:

I've got a tech scheduled to come out tomorrow night now, but they wanted to sell me "protection" from being charged for the service call, they say if it's inside my house, they will charge me for the call.

Seems to me like a signal strength issue coming from the street maybe?

 

[Fardringle]

Try a TRACERT to see WHERE the packet loss is happening. If it's outside the Comcast network, there's nothing you or they can do. If it's inside your house (i.e. before you get to the Comcast network) then it's a problem with your equipment. If it happens on any of the hops between your modem and the rest of the Internet (beyond Comcast's network) then you might have a complaint with Comcast that they should take care of.

If you think it is a signal strength problem, have you tried logging in to the modem to see what the up and down signal strength actually is?

 

[Passafire]

Try a TRACERT to see WHERE the packet loss is happening. If it's outside the Comcast network, there's nothing you or they can do. If it's inside your house (i.e. before you get to the Comcast network) then it's a problem with your equipment. If it happens on any of the hops between your modem and the rest of the Internet (beyond Comcast's network) then you might have a complaint with Comcast that they should take care of.

If you think it is a signal strength problem, have you tried logging in to the modem to see what the up and down signal strength actually is?

Some of my skills are a bit limited dealing with this kind of stuff, as I haven't had issues in years. I did ping my router to see if there was any packet loss between me and the router (I'm directly connected to a gateway combo though), results were good/normal.

Pinging google, I see packet loss of up to 5% and the highest ping takes over a full 2 seconds, average is 150ms.

I am unsure what a good range for signal strength actually is. Below is a picture of my modem's current downstream:

 

[Passafire]

anyone?

 

[Gryz]

Listen to Fardringle's advice.

First step is to find out where the packet-loss is happening.
A useful tool is traceroute (called tracert under Windows). Google how to use it, and what it does.

It is unlikely the packet drops happen on your home network.
There are 2 more likely scenarios.

1) Drops happen on the link between your cable-router and Comcast's router. Traceroute can indicate this. If this is the case, you can log in on your cable-router, and look at stats like bit-errors, etc. (No idea if this is possible if you have a separate modem. In my country all DSL- and cable-ISPs use routers with integrated modems at the customer location). If you can prove that the drops are because of problem on your access-line, you can complain to your ISP.

2) Drops happen further down the network. Either inside your ISPs network. Or in the network of another ISP. Or at the connection-point (peering) between two ISPs. In any case, there is nothing you can do. You can complain. Sometimes ISPs will take action. (E.g. 1k World of Warcraft users complaining about their connection to the WoW-servers). But usually there is little the ISP can do.

But first you need to find out exactly where the drops are happening. No magic can help you.

 

[Passafire]

Pinging google.com 100 times gives me this result:

min 64, max 1700, avg 160, packet loss 2%

This is my tracert for google:

#2 would be the router basically out on the street level? Seems that is the one with the highest latency and packet loss.

 

[Gryz]

Yes.

You should do a few traceroutes, and see what's the average. Just one snapshot might not give enough decisive information.

That being said, the nr2 router did drop a packet. Also, the fact that the latency there is higher than hops behind it, indicates that that router's control plane (as opposed to the forwarding plane) might be overloaded. In other words: something that the cable company *might* be able to fix.

Nothing you can do yourself. You should repeat your test a few times, so you'll be sure of what you see. And then call your ISP and tell them you got packet loss, and tell them where you think it happens. Good luck.

 

[theevilsharpie]

You should do a few traceroutes, and see what's the average. Just one snapshot might not give enough decisive information.

On Windows, pathping is a better tool for diagnosing packet loss.

 

[Passafire]

On Windows, pathping is a better tool for diagnosing packet loss.

Ran a couple pathping's. They all look similar to this:

Now I'm really confused. Looks like everything except pc to router is completely jacked up? :'(

 

[theevilsharpie]

Now I'm really confused. Looks like everything except pc to router is completely jacked up? :'(

Yep. Looks like the connection to your ISP's gateway is the problem.

 

[Passafire]

Yep. Looks like the connection to your ISP's gateway is the problem.

Tech just left after 2 hours. Replaced all my tips, took me off unnecissary splitters etc. Helped my already good signal strength become perfect. No change with packet loss though. He put on a rental modem, same issue. Took it back off and put mine back on and gave up.

He says everything is testing good and he can't for the life of him figure out where the packet loss is coming from. Huray, looks like im SOL.

 

[theevilsharpie]

If you've ruled out your own equipment and connection quality issues, then the only plausible explanation for inexplicably long latency and intermittent packet loss is that your ISP's network is suffering from excessive congestion.

I haven't personally used a cable ISP, what I've seen through the eyes of others is that cable ISP's seem especially willing to operate their networks as close to their maximum capacity as possible, which doesn't leave much room to service bursts of traffic without queuing or dropping packets.

That being said, you could try to bring this performance issue to the attention of your ISP. Although most consumer ISP's don't make any guarantees about performance, their "wiggle room" in that regard is that they offer you a specific amount of bandwidth within their own network, but can't control the performance of external networks. However, your packet trace shows the poor performance begins as soon as it leaves your network, which suggests that your ISP can't even provide the advertised speed within their own network. I'm not sure how far that line of reasoning will take you, but the only thing you have to waste is your time.

 

[Passafire]

The tech ruled out all of my equipment, but he was stumped as to what was continuing to cause packet loss. He quite obviously had never seen a trace route before and hadn't a clue what I was trying to tell him.

He did, however, schedule me to have a line level tech come out on Wednesday to look into it further.

My biggest issue is I can't find anyone that knows what they are talking about, I mean this tech was ok, and I'm sure he does just fine for "most" of the work he does daily, but the phone techs, internet-chat techs don't even understand the concept of ping.