Keep that damned DSL link up please

VanDan · Guru Joined: 30 Sep 2002 Posts: 586 Location: Australia

For whatever reason ( I blame Telstra ), my DSL link keeps going down.

I have created a script which kills all stray pppd processes, zaps the status of the speedtouch service that controls the DSL modem, rmmods the USB drivers from my kernel ( creating an oops, but it doesn't seem to matter ), then reloads the USB drivers and starts the modem again.

Now I do I monitor the link so I can automate the process? I know a little Perl, so I could use something link Net::Ping to check internet access, but I was wondering what is the 'proper' way to do it.

There is a message in my dmesg output that always indicates the link has gone down, but I'm not sure how to monitor that ( and I'm not sure what the exact message is right at the moment because ... my bloody home PC is offline )

Or maybe someone has already written something that does this?

James Wells · n00b Joined: 10 Sep 2004 Posts: 57

Greetings,

Check your PPP config to see if you are doing keepalives, if not, I would recommend turning it on, just in case it is dropping due to inactivity. As for the best way to monitor it, ping really is the easiest way. Something like ping -i 5 and if it fails to get response for more than 5 seconds, then it is most likely down.

volumen1 · Guru Joined: 01 Mar 2003 Posts: 393 Location: Missoula, MT

Just out of curiosity, what versions of speedtouch, ppp and kernel are you using? I started having this problem in what I think was the later versions of 2.6.7 kernels. Or, maybe it was the version of speedtouch or pppd that I hit around that time. Which speedtouch modem do you have? Which firmware are you using?

I have the 330 purple and am having your same problems.
My current kernel is 2.6.7-hardened-r17
My ppp is 2.4.3-r1
and my speedtouch is 1.3.1-r2

If you are using 2.6.10 then there are some real problems with modem_run and that version. Here's some links to more posts on the subject.

https://forums.gentoo.org/viewtopic.php?t=186918&highlight=
https://forums.gentoo.org/viewtopic.php?t=273947&highlight=
_________________
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-- www.howsyournetwork.com

nobspangle · Posted: Mon Jan 31, 2005 8:30 am Post subject:

If you can afford it, get yourself one of these they have all kinds of online monitoring and self testing for the line built in.

vtsontsi · n00b Joined: 28 Jan 2005 Posts: 1

I have the same problem with my speedtouch modem which is installed in a linux box running as a gateway for my home network. On the router box i don't have gentoo but mandrake 10.1....however the story is the same:

Observation #1: the link goes down very very often, but not at periocal intervals. Sometimes it stays up for days sometimes it goes down every 5 minites.

Observation #2: this damned behaviour whasn't happening when i had "Smoothwall" distribution on the router

Conclusion #1: with all traffic patterns in my network the same i come to the logical conclusion that mandrake's 2.6.8 kernel makes the difference. Smoothwall's 2.4.x was fine

I tried to find out WHEN the link was going down. After a lot of testing and trying different traffic patterns i come to the surprising (for me) observation that:

Observation #3: The link going down is directrly related to the Bittorrent applications. It seems that the fast opening of connections causes problems. All other p2p applications dont't cause problems.
It seems this is a known issue for bittorrent clients. All the suggested solutions at azureus FAQ didn't work. The link goes down 1-5 minites after the client is launched from any computer on the network.

I made a script in perl like u did, to bring up the connection...the script understands when the connection goes down by checking the /var/log/kernel/errors for the line "hub 1-0:1.0: port 1 disabled by hub (EMI?), re-enabling..."

Of course this is a solution that fixes the effect and not the cause. The bottomline for me was to stop using bittorrents, which is very painful

hope i shed some light....

thebigslide · Posted: Mon Jan 31, 2005 5:30 pm Post subject:

I had this same problem with my speedstream modem and bittorrent. I resolved the issue by limiting the throughput of the interface using traffic control (www.lartc.org) on my linux router. The problem seems to be that the buffer in the modem would fill up and be kept brimming by bittorrent, greedy as it is of bandwidth, and then the modem would crash after a few hours. By limiting the throughput, I moved the buffer to the linux router and the modem was under much less load. I just shrunk the upstream bandwidth by degrees with until iptraf showed me a miniscule decrease in throughput. I never had the problem again.

xming · Guru Joined: 02 Jul 2002 Posts: 441

If you are using kernel > 2.6.10 please use the kernel driver to load the firmware and to monitor the line, before I did this I had to restart the PC at least once a days (rmmod speedtch, stopping hotplug, killing modem_run then redo everything wouldn't help). Since I have been using the kernel driver + hotplug to do the loading and monitoring, the link has been up for more then 10 days (at least resync + restart pppd are autogimatically now).

PS: visit my site for more details

xming
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volumen1 · Guru Joined: 01 Mar 2003 Posts: 393 Location: Missoula, MT

Which speedtouch modem do you have? I have the 330 purple and kernel hoplug firmware loading sucks for me. The modem will be up for only a few minutes and then it crashes hard and I can't get it to come back without a reboot, so I'm still running modem_run on 2.6.9.
_________________
I was born with a freakin' dice bag on my belt.
-- www.howsyournetwork.com

VanDan · Guru Joined: 30 Sep 2002 Posts: 586 Location: Australia

Thanks everyone for replying.

I've been particularly busy recently, but anyway, better late than never...

I'm using the cheapest model of speedtouches. I honestly can't remember what model number it was, but it looks like the one pictured here ( light-blue stingray-type thing, for those not interesting in clicking ):
http://www.clubic.com/shopping-3771-0-alcatel-speedtouch-usb-avis-des-visiteurs.html

I'm running a 2.6.8-gentoo-r1 kernel - I've only got a Celeron 333 connected to the modem ( this is my gateway by the way ), so I don't upgrade my kernel unless I need to, and have the time to

I'm running pppd-2.4.2.

Now, while I understand that it would be great if there was some tweaking that I could do to make it "just work", I've come to realise that this is not going to happen. For example, whenever this is a network outage ( Telstra's service is going downhill fast since the government started offloading to it private investors ), line sync is lost, and doesn't come back until you power-cycle the modem. For USB modems, that means rmmod-ing the USB driver module out from underneath things, and then modprobe-ing them again ( or pulling the USB plug out and re-inserting that, but I can't write a script to do that ).

So I really think some sort of monitoring software is what we're all after. That's what I'm after anyway.