Intermittent packet loss: Can anyone help me?

[neotechnet]

Hi all, been dealing with this problem for a few weeks at a client and banging my head against the wall at this point.

They have a network of maybe 15 users, Time Warner modem, 3 Trendnet powerline adapters and 2 trendnet 8 port switches and 2 ubiquiti unfi wireless units.

Starting about 3 weeks ago they were getting massive packet loss on their TW line making the internet almost unusable. TW saw the packet loss coming directly from their modem and worked on things on their end which really didn't amount to a lot.

So TW finally came out and replaced the modem. I'm still seeing packet loss, but here are the odd points.

I had a brand new sonicwall hooked up to the TW modem and I was seeing packet loss to the internet. I take my laptop and plug into the TW modem and it started running fine, no request time outs. I tried this a few more times and the results was clear, PL to google.com when behind the firewall but no PL when plugged into the TW modem.

So I took out the firewall, put the modem into NAT mode and connected. Random PL continued, it will drop anywhere from 3 to 10 packets at random to google.com

But here is the thing, I get zero packet loss when pinging the lan port of the modem which is 10.0.0.1. So I'll get PL to google.com but perfect pings to the modem.

Does anyone have any ideas on this on where else I can look? I thought maybe there was a device disrupting the network but how could I get perfect pings to the modem itself? If I'm timing out on google.com it has to be a TW issue which they said it isn't at this point.

If anyone can think of anything to try, any tools I can use, anything at all to rule out an internal network issue I would greatly appreciate it.

 

[Moltuae]

Could be an MTU or packet size issue.

Have you tried pinging with varying packet sizes?

 

[neotechnet]

Oh I want to add that I have been running a ping since last night about 10 am, pinging the internal TW modem and google.com.

Can you believe that I got zero packet loss all night up until about 8 am this morning and now I'm starting to see random packet loss again. If it this were a TW issue how can it run clean all night and only start PL in the morning? It just doesn't make sense to me at all!

 

[Nerm]

Probably already tried this but want to throw it out there since you didn't mention it. Have you tried swapping the cable from the modem to the internal network?

It does almost sound like an MTU type issue. You mentioned you took out the Sonicwall and set the modem to NAT mode, but what does the modem now connect to?

 

[neotechnet]

The modem now connects to a trendnet 8 port switch which connects to the rest of the network, it's acting as the firewall now.

I have tried several cables but I could always swap it out again. What I don't understand is how could it ping fine all night, figure about 10 hours, then start getting packet loss starting at about 8 am this morning.

I observed the packet loss on my laptop plugged into the trendnet switch plugged directly into the modem so it wasn't touching the powerline adapters.

 

[Martyn]

You could try tracert www.google.com and see if it points to a delay in one of the hops

 

[trevm999]

You could try tracert www.google.com and see if it points to a delay in one of the hops

Or MTR which does a trace route+ ping

 

[mr m]

What I don't understand is how could it ping fine all night, figure about 10 hours, then start getting packet loss starting at about 8 am this morning.

There is less traffic at night than during the day therefore latency and collisions are less and fewer. It's possible that your ISP's network can't handle the increased daytime activity (collisions) so packet loss increases.

You stated that you get zero packet loss when pinging the LAN port of the cable modem but as soon as you go out to the WAN the PL stars. Like you said a jabbering NIC or other faulty network device would cause PL on your LAN which you're not seeing.

It sure sounds like the ISP is at fault but good luck trying to prove that. Have the client call and complain and demand that this issue gets escalated at the ISP.

 

[Nerm]

Could you post a traceroute screenshot to say google.com during peak and off-peak hours?