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Field Notes It Just Stops Working
R'ykandar Korra'ti, postmaster for a small co-op ISP, lives near Seattle with her partner Anna. Having previously shipped mail products at Microsoft, she is now looking at grad school in a field so esoteric it doesn’t really have a name. Potential faculty advisors can reach her a email@example.com.
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"I DUNNO, I just keep getting dropped."
"Any time of day? Anything specific you're doing when it happens? Any particular machine you're connecting from?"
"Nope. I'm on, and then I'm not. Poof! Gone."
"That doesn't give me a lot to work with, y'know. C'mon, gimme something. A hint, a clue, anything."
"I've told you all I know. Sometimes I just get dropped. Can you fix it?"
I tell her I'll work on it. There's not much in the router logs, but occasionally our traffic really does drop away, indicating that something is going wrong-but only for a minute or two at a time, after which everything returns to normal. No errors, no pattern, just every so often-no traffic. It's strange. Then we get lucky:
Ring Ring goes the telephone attached to the DSL.
Thunk Die goes our IP connection.
You are kidding me, think I. And yet, it reproduces: if someone calls the DSL phone number-the one nobody uses and no one's supposed to know about-our connectivity dies. The telephone company's number-one service selling point, the major calamity they claim you'll never have to worry about, happens-in flashy, blinky detail.
And yet, we're only 900 feet from the substation. This shouldn't be happening. I check cables, reset everything, and even clean the connections to see if that helps. But, of course, it doesn't. So I call the telephone company. "You know how you guys promise you'll never have your connection interrupted by incoming phone calls? Guess what's happening? We can be DoSed by telemarketers."
Maybe It's the Copper ...
A tech comes out the next day and finds that, inexplicably, we test as over 3,000 feet away from the substation, far enough away that a cranky squirrel could cut us off with a small compass magnet. Eventually, we discover that back when our neighborhood was wired, all the phone lines were bundled together and every line sent to every building on the block, the idea being to avoid ever needing to run new cable. That's fine if your entire world is analog voice, but from a DSL standpoint, every linear inch of those branches counts as distance from substation, dropping your signal strength.
Happily, the problem had a quick and easy fix. All the side branches of the line were disconnected, and a note was added saying, "DO NOT RECONNECT. DSL PORTION IN USE." Ta-da! A distance of only 900 feet, a much stronger signal, and most importantly, no carrier loss on rings.
The moral of the story: don't assume that a connection problem is esoteric or even caused by software. Sometimes it's just a matter of the copper. Always, always have the telephone company guys check the actual DSL signal strength upon install, even if they're sure they don't need to; you never know what else might be hooked up there, just waiting to confuse you later. And don't take their word for it on distance-to-substation. You have no idea where those wires might be going, and neither do they. Find out. They have the tools; they have the technology-make them use them. You'll be glad you did. Particularly once telemarketers find your DSL number.