Losing your internet connection is no laughing matter. Here's what to do when disaster strikes.
Life is full of unexpected surprises designed to trip us up when we least expect it. But these days there is a new, oft-overlooked catastrophe to worry about: the loss of your broadband connection. One minute it's there, the next it's gone. No e-mail, no blogs, no downloads, no Internet radio. Nada. Zip. Diddly-squat. Accordingly, this month's Networking column is devoted to helping you avoid a world of pain and get back online double-quick.
First things first. Although it's tempting to think the problem lies at your end, with your hardware and software, the odds are that it doesn't.
The Internet is a network of nigh-on infinite connections, with you and your PC comprising but a tiny cog in a vast gearbox. In short, if you have a connection problem, it's probably wise to start with your ISP and find the current network status.
The next step is to power-cycle your ADSL (asymmetric digital subscriber line) modem or router - in other words, pull the power lead out, count to 10 and then plug it back in again. This will usually fix your connectivity problems, so it makes sense to give it a go first.
The first stage of establishing an ADSL Internet connection is to obtain what I call "an electrical connection" to your phone exchange. Soon after you power up your ADSL modem, it will automatically attempt to synchronise with the DSLAM (Digital Subscriber Line Access Multiplexer). This is a gizmo at the exchange that links many customer ADSL connections to a single, high-speed ATM (Asynchronous Transfer Mode) line - see FIGURE 1.
So all ADSL modems and routers have a sync status LED that indicates whether or not you have a physical connection to the exchange. If this LED isn't on, you've not synched. If you use Windows dial-up networking to connect, it may somewhat misleadingly tell you it can't detect a dial tone, but it's the same thing.
Although I have a fairly new Netgear DG834G router, it can take anything up to 10 minutes to sync - the LED stays off, then flickers yellow then off, before finally going green and staying on permanently. But normally, most ADSL modems will sync within a minute. If you can't sync with the exchange there's no point in proceeding any further - this is a pretty fundamental show-stopper.