After months of woe with my Comcast cable connection, and a couple months of flirtation with indie DSL, I called Comcast out for a third service visit to focus on the external wiring. (Aside: This took some convincing from the service rep on the phone; more on this later.)

I realized that our house had a bunch of old exterior cable wiring including a dodgy splitter, left over from when we bought it, and entirely unused now. Comcast hadn’t decided to look at this before, and it hadn’t occurred to me that it would be related since I have no idea how things are wired downstream of their lock box except inside my part of the house, but this time I decided to be more careful. When the tech arrived, I asked him to open the lock box and disconnect everything in there that I’m not using.

Also, the tech took a look at the wire from the pole to the lock box and said it doesn’t meet their current standards and offered to replace it.

Other than some hilarity involving division of labor (one guy calls in the order for new wiring, a separate guy shows up a day later and strings it, then the first guy comes back a day later and actually connects it inside the lock box, because the first guy doesn’t have the cherry picker truck to string the cable and the second guy doesn’t have the key to the lock box?), this went pretty smoothly.

So now I have shiny new wire from the pole to my house, we disconnected all the other old wiring so from the lock box the only connected wiring is my own new indoor wiring, and, knock on wood. one of these things was the problem and the problem is no more.

(This was a month ago, and I hesitated to write about it immediately for fear of jinxing it, but now that it’s been a month with none of the same old problem, I’m feeling better about it.)

The promised aside: the service rep I spoke with on the phone was either a genius or knew just enough about networking to be dangerous; I’m not sure which. He asked how I knew it was Comcast’s problem and I said I’d tried replacing the modem already so what else could it be. He said what if it’s my router; I should try connecting my computer directly to the router and see if the problem still happens. I explained how the problem only happens an average of once every two weeks and there’s no way I’m disconnecting all but one computer in the house for weeks on end, and why should I suspect my router anyway? Then we got in an argument about 192.168.100.1 and whether it is indeed the address of the cable modem, as I believe, or, as he said, “the address my computer uses to get online” (whatever that means). I was convinced he was stonewalling me and he was convinced I was being difficult and this was going nowhere so finally I said just send a tech out and he said OK but we’ll have to charge you if it’s not our fault and I said fine, you’ve already done that twice and I’ll just have all the charges reversed once it does turn out to be your fault. (And I did call back later and Comcast was happy to refund the earlier service charges once they saw they’d had 3 calls for the same issue.)

So anyway. I didn’t find any of his facts or arguments highly convincing but it did get me thinking — how do I know my router’s not acting up? It doesn’t seem to be, but maybe. It is bleeding-edge OpenWRT, after all, totally awesome in its power but not the most mainstream and tested thing. So the next time the usual problem happened (conveniently, before the wiring repairs mentioned above were finished), instead of power cycling the modem I disconnected and reconnected the ethernet cable between modem and router, thus toggling the ethernet link state. After that, connectivity was restored — I could ping both the router and external sites — and the modem reported no downtime.

That seemed like a smoking gun, but it doesn’t explain why each Comcast wiring repair changed the frequency of the problem. At this point I’m pretty sure I’m dealing with multiple problems, interacting or at least masking each other in complicated ways, and making troubleshooting that much harder. It really seems like the wiring repairs helped materially, but if I do see more “modem crashes”, I’ll be looking hard at the router first.

(And to make things even more confusing, I’ll note I’ve also seen a handful of “T4 timeout” problems where the modem complains to its logfile and then reboots itself; that’s definitely a Comcast-side problem; it’s also wholly distinct from the one I’ve been calling “the problem” and easily identifiable since the modem clearly identifies it as such; it’s also a lot less annoying because it only seems to happen in the middle of the night and it fixes itself within minutes.)