Wire why

[j4]

I wrote a long blog post on paper, and was looking forward to typing it up on a computer with a real keyboard, but got home to find that we had no internet access.

This may seem like a slightly odd thing for an internet addict to say, but: I hate home networking. I wouldn't hate it if it worked, of course -- if it was like electricity, working at the flick of a switch, no configuration required, total failure so rare that we're still talking about the last time it happened -- but it's never like that.

I'll freely admit that the real problem exists, as they say, between keyboard and chair. I don't understand most of the component layers of the problem, I don't really understand the way they interrelate, and as for understanding how to fix them when they go wrong -- hopeless.

My view of the setup is something like this: my laptop has a radio-thing in it that lets it talk to the Airport; the Airport is plugged into the router; the router is plugged into phone socket. So INTERNETS comes out of the phone socket, and the router speaks fluent internet, and interprets it for the Airport, which can shout loud enough for other stuff to hear it. Roughly. I can vaguely tell where the problem is (if the computer can get a wired connection directly via the router, then the Airport is probably the problem; if it can't, blame the router) but that's not a lot of help: if nothing has changed, why has one of these devices stopped working? Why does rebooting so frequently fix it? I feel like a superstitious idiot unplugging the magic white box and plugging it back in again, but 8 times out of 10 it fixes things. Sometimes unplugging doesn't work, but a 'hard reset' does; sometimes, power-cycling the router fixes everything. Sometimes, nothing works. Like today.

The other problem is that even if I really understood DNS, TCP/IP and so on [waves hands as if trying to unravel a large bundle of unidentified greyish wires], the INTERNETS would still be coming THROUGH THE PHONE SOCKET, and this part of the setup is a) magic and b) subject to the whim of BT and Eclipse. So any attempt to do the right things with the computer, Airport and router is constantly undermined by the fear that things are mysteriously Not Working outside the realm of Stuff I Control. It's not working... Have I got something wrong? It's working again... Is that because of what I did, or because Mr BT turned off the switch marked 'BOTLEY INTERNET FAIL'?

There's also the lurking worry that by buying a cheap router and a second-hand Airport I have doomed the whole project to failure. More superstition, probably: do the gods of internet require a costly sacrifice? But this is secondary to the real problem: too many components and not enough understanding.

So, rather than asking (as I have done previously on LJ) 'please to make mr understand internets', I will try to ask some more specific and practical (and probably dumb) questions:

1. How can I test the ADSL connection without using the possibly-rubbish router?

2. What could make a correctly-configured Airport/router suddenly stop working for no apparent reason? (If the answer is 'nothing' then my inference is that it's not correctly configured...)

3. If component A is intermittently malfunctioning, is it possible that rebooting component B could affect it? (If not, I fear I'm left with either loads of crazy coincidences or the increasing certainty that none of the components of this mess actually work reliably.)

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Comments

[crazyscot.livejournal.com]

1. Not much you can do short of trying another router. Alternatively, most (all?) routers have a web interface for config and diagnostics; it'll tell you about your line status and whether (for example) your line tripped out. Particularly if your line's usual ADSL speed has only a small noise margin, your line might be susceptible to tripping off and/or retraining from time to time - but this should be a quick thing, outage of only a minute or two.

2. Umm. Radio interference? Depends on the distance between mac and airport, whether there's anything nearby emitting junk radio noise, other folk using the same wifi channel, cosmic rays, power surges...

3. Very unlikely. Rebooting B and it starting working again is arguably indistinguishable from the case where you did nothing for a couple of minutes and then tried again to see if A had spontaneously come back to life.

[addedentry.livejournal.com]

2. A cordless phone?

[crazyscot.livejournal.com]

Vaguely possible, but unlikely; I thought they used different frequencies. (Wifi 2.4GHz or 5GHz; DECT cordless phones 1.9GHz; old cordless phones down in the two-digit MHz. However if there's foreign gear of questionable legality involved, who knows?)

[hoiho.livejournal.com]

Bluetooth & microwave ovens also use the 2.4GHz band (only 801.11A uses 5GHz, and that's not licenced for Europe)), as do some model aircraft remote controls.

All, except microwave ovens, use frequency-hopping, so shouldn't block a WiFi signal to the degree that it stops working entirely. And a microwave shouldn't normally interfere unless it's either close, large, or leaky.