my internet adventures

Hi there!

It's reasonable to think that complexity increases as technology advances, but the adventures I have been having with my ISP as of late really surpass my capacity of understanding.

Let me explain you this little story. First some background. I'm a DSL user located in barcelona, spain. Our servide provider is ya.com and it has been for about 5 years now. We've been very happy all this time, with minimal downtimes and continuous increases in throughput (we started at 256kbps and are now at 4mbps).

Last year (2005, that is) ya.com bought a fiber network called albura. Not many people talked about this but it's basically the beginning of my small horror story. Thanks to the albura network (AFAIK) ya.com has been able to offer 20mb download rates using the so-called adsl2+ technology. Ya.com clients from 2001-2002 did not use this network and instead relied on lines that were leased from Telefonica, spain's main operator. This circumstance prevented our migration to adsl2+. Thus we were still using adsl2@4mbit speed in July this year. and btw our modem router was the ancient 3com 812 officeconnect which does not support adsl2+ anyway.

In july 2006 I started observing strange behaviour of my modem. In general it would work, but periodically the modem would stop working for some time, apparently rebooting itself (although this I did not notice). It mostly worked so I did not bother too much. However, on July 26th (more or less) it stoped working completely. The modem was still synchronized but there was no way to send-receive packets. Since I was on a trip I could not check these facts and instead thought that I'd be able to easily correct the incident after returning home.

But once I was back home things just got worse. I could not make the modem work despite my best tries, and worse, the modem suddenly lost synchronization and stayed so. At this point (I guess Aug 1st or 2nd) I contacted tech support, who provided me with some new configuration parameters (which for some reason nobody had told us we had to change). But this did not solve the problem. We were told to wait for technical staff to contact us on our problem.

Since I didn't want to wait I made a small web search and imagine what I found. Apparently ya.com was in the process of migrating all 2001-2002 users to the albura network, but something went wrong and lots of people in my area were having the same problem. What follows is a couple of weeks trying to contact tech support without luck. Some three weeks later (!) finally a technician contacted me and told me that 1) ya.com people had checked the remote modem station and that 2) a new router was needed for the adsl2+ technology, which would be sent in shortly after. Then he told me that even though my modem was not adequate we could use a patch to make it work. This patch consisted in telneting into the modem and issuing the commands:

set adsl open dmt
set adsl reset

Back at home I tried, and effectively it resynchronized after a minute. Interestingly I had to reconfigure the modem to act as default gateway, something which I had never modified but suddenly was not active anymore. Anyway.. it was working and after 4 weeks I was happy again. But now is when the most perplexing starts, a new problem that I still haven't been able to solve at this point.

With the modem synchronized everything seemed to work well. Everything except gmail. For some unknown reason, after logging into gmail I am completely limited. Emails can only occasionally be viewed, sending is impossible and chat also doesn't work. And this happens on all computers at home. ALL! So it must be something of the network. But what? I have checked that both TCP and UDP work and I even played with modem parameters such as the MTU and other parameters that I can't remember. It can't be a software problem since the same computers that exhibit this problem work perfectly in a different network. I have tried to google for similar experiences, but without luck so far. It's so perplexing that I don't even know if I would be able to explain the problem correctly to a technician.

I think that this maybe has some relationship to the technologies used by gmail. I tried to find out something. GMail uses mostly AJAX to minimize transfers between client and server. AJAX seems to contain three components: XMLHttpRequest+JavaScript+XHTML (simplified). Individually searching for problems with these technologies also has yielded no answer as to why I may have problems accessing the site from my network. Maybe it is google that doesn't like our network address?? Or could it be that the "patch" does not provide full internet service??

As said, I'm perplexed. Luckily I do most interneting from work, where I do not have this problem, but it is still annoying getting home and not being able to access gmail other than through the POP3 interface.

So far my horror story :) If you somehow came here and have a suggestion I'd really like to hear it.

In the meantime I'll get back to some reading/hacking :)
ByeBye! -- izzu

UPDATE:

What you just read is what I wrote yesterday at night. But I couldn't submit it to blogspot. Imagine why. However, the incident has allowed me to confirm a previous hypothesis that I had discarded: The problem with my DSL line lies in the fact that the ATM/ADSL network cannot support large bursts of outgoing data. This is what I thought when I started to play with the MTU parameters, but my tests didn't work back then. Thus I had since discarded this idea. But yesterday, after seeing that I could not submit the post, I tried to upload it to a server that I can access from work so that I could send it today (and this is what I'm doing now, btw). My surprise: the sftp command stalled. When this happened I was reminded of my previous hypothesis and decided to test it. Luckily sftp has a switch (-B) that allows you to specify how large the blocks of data are that are going to be sent over the network. I tried with -B 256 and it also stalled, but it went further. Then I tried with '-B 16' and I was able to transfer the document. After noticing this I have been playing a little with the UBR and CBR parameters of the ATM line but I have had no success. I think I will try to find some info on this in the web or give a second chance to an adsl2+ router that a friend let me. Anyway, as you can imagine, the worst of all this is not the internet problem itself but the nervousness of days and days of tuning router parameters without success.

Well, back to work for today
-- izzu