Intermittent loss of connectivity

[jbert]

Hi folks.

Slightly mystifying problem here. For over a month (I went away on holiday hoping the problem would self-correct) my broadband connection will occasionally "drop out" for 5-20 seconds before coming back. The severity of the problem fluctuates a lot, with 5 secs off / 2 mins at some times and 10 secs off / 5 secs on at the worst. The connection is then effectively unusable.

I'm not exactly sure, but I think the problem does get worse in the evening, so could be load related I guess.

I have a terayon terajet cable modem and normally access it via a wifi router but have experimented with taking that out of the loop and direct-connecting (via ethernet), with no change. I've direct-connected two different PCs (desktop and laptop) under two different OSes (Win XP and Ubuntu) with no change (so I don't think its a software/firewall issue).

The cable modem lights seem "normal" during a failure episode. i.e. the data light continues to flash and the three steady lights remain steady.

When running, the link is at a good speed (perhaps not the full 4mb, but a good speed) but the periodic "nothing" is maddening.

When the problem occurs, traceroute shows up the wifi router at this end and then nothing (the next hop would I guess be the UBR).

I don't seem to be able to ever be able to ping the UBR (filtered?) but long running pings to www.ntlworld.com and a router one hop behind the UBR go from almost 100% success to a flat zero, in sync, when the problem occurs (so I don't think its a web/cache issue).

I think the problem approximately dates to the recent speed upgrade, but I wouldn't swear to that.

I've read the "read before you post" guidelines, but since the problem is an "all or nothing" one, I don't see that traceroutes and ping times are particularly relevant (they either show decent connectivity or an inability to reach the UBR), but I can happily include them if desired.

I'm in Nottingham (NG5 postcode), if that's relevant. UBR IP shows as 10.225.116.1.

Could this be congestion? If so, I'd expect that to manifest as a more general packet loss, not the 100% ON/100% OFF I am currently experiencing.

I've emailed NTL broadband support with no reply and will be calling them later, but I know from experience that intermittent problems are a pain to track down, so any additional advice anyone has would be gratefully received.

thanks in advance.

jb

[Mick Fisher]

There have been a few reports of similar problems with the Tjet. Usually replacing it with a 250 seems to fix the problem.
The consensus seems to be that the Tjet can't handle some aspect of the upgrade, although I have to say I have a Tjet on 10meg, OK it won't do the full 10meg but (touch wood) I don't suffer from drop outs of the kind you mention.
You will have to call TS and ask for an engineer to visit.

[jbert]

Thanks very much for the reply. Nice to know that there may have been similar problems.

[budwieser]

Hi folks.

Slightly mystifying problem here. For over a month (I went away on holiday hoping the problem would self-correct) my broadband connection will occasionally "drop out" for 5-20 seconds before coming back. The severity of the problem fluctuates a lot, with 5 secs off / 2 mins at some times and 10 secs off / 5 secs on at the worst. The connection is then effectively unusable.

I'm not exactly sure, but I think the problem does get worse in the evening, so could be load related I guess.

I have a terayon terajet cable modem and normally access it via a wifi router but have experimented with taking that out of the loop and direct-connecting (via ethernet), with no change. I've direct-connected two different PCs (desktop and laptop) under two different OSes (Win XP and Ubuntu) with no change (so I don't think its a software/firewall issue).

The cable modem lights seem "normal" during a failure episode. i.e. the data light continues to flash and the three steady lights remain steady.

When running, the link is at a good speed (perhaps not the full 4mb, but a good speed) but the periodic "nothing" is maddening.

When the problem occurs, traceroute shows up the wifi router at this end and then nothing (the next hop would I guess be the UBR).

I don't seem to be able to ever be able to ping the UBR (filtered?) but long running pings to www.ntlworld.com (http://www.ntlworld.com) and a router one hop behind the UBR go from almost 100% success to a flat zero, in sync, when the problem occurs (so I don't think its a web/cache issue).

I think the problem approximately dates to the recent speed upgrade, but I wouldn't swear to that.

I've read the "read before you post" guidelines, but since the problem is an "all or nothing" one, I don't see that traceroutes and ping times are particularly relevant (they either show decent connectivity or an inability to reach the UBR), but I can happily include them if desired.

I'm in Nottingham (NG5 postcode), if that's relevant. UBR IP shows as 10.225.116.1.

Could this be congestion? If so, I'd expect that to manifest as a more general packet loss, not the 100% ON/100% OFF I am currently experiencing.

I've emailed NTL broadband support with no reply and will be calling them later, but I know from experience that intermittent problems are a pain to track down, so any additional advice anyone has would be gratefully received.

thanks in advance.

jb

Had the same problem myself mate and the Tech came and gave me a 250! Telephone CS and ask for them to check it their end, they got 100% packet loss and also said that they could see that the 210 had been re-booted 497 times! :Yikes:
Wondorous speeds followed! :D

[jbert]

Good to know. I now have an engineer coming by later this week. Tech support - I think wisely, given the nature of the problem - weren't that interested in trying too much in the way of diagnostics over the phone.

If he doesn't find anything specific I'll ask if he can try replacing the cable modem, given your experience.

Thanks very much for the data point.

[jbert]

Problem solved. The engineer turned up and saw my old cable modem and did a replacement to a newer model. One mac switchover later and things were working well. I've had several hours now without a dropout.

Note that I was only on the 4mb service, so it doesn't seem to be quite as simple as "the old terajet's can't handle 10mb".

Great service from NTL and thanks to the people here who gave additional info.