다음을 통해 공유


Infinity = 40

At last our phone company has managed to drag a strand of high-speed cable across the six miles from the exchange to the green box at the end of my garden. In a flash I've been transported from the "back of beyond" into the exciting world of the "digital now" (at least, that's what it says on the publicity blurb they sent me).

According to the leaflet, the new service is called "Infinity" and is immediately available with speeds "up to eighty times faster than ADSL". Of course, you do have to take into account a few over-excitable marketing terms here. It's actually still ADSL, but closer to you than it was before. Also, the multiple increase in speed simply reflects how slow it was before (less than 2 MB in my area). And when I phoned and asked if "Infinity" was a description of the actual speed I could expect, I wasn't really surprised to discover that it's actually around 40 MB maximum. I'm wondering how long it will be before the Advertising Standards Agency people start to ask difficult questions.

What they provide is "Fibre to the Cabinet" (FTTC), so you still have wet string between the cabinet and you (note that I refuse to call it "Fiber" on the grounds that it's buried under our green and pleasant English fields). And at the pointy end you get a modem that translates the signal into a PPPoE interconnection that any suitably-equipped router or hub can consume.

I always said I'd upgrade my ADSL line when FTTC did arrive, and I was on the phone to a business salesperson at BT (the phone company) the same day as I got the letter. Obviously take-up is somewhat slow because I got a fitting date only a week ahead; maybe because I have a business service rather than a residential one. And within three days they'd delivered by post the hub/router, a box of cables, and a welcome pack. The modem itself, and hopefully the requisite installation skills, would be coming with the engineer.

And everything did arrive on time, and worked. The engineer replaced the wall socket with a new one (or rather, one exactly the same as the old one but with an "Infinity" label), went off down the street to the cabinet and wiggled the wires for half an hour, plugged in the modem, and I was almost instantly cable-enabled. He also plugged in the hub/router they provided, and did a speed test to prove it would give 40 MB down and 10 MB up.

But then we got to the bit where I asked him to configure the hub with wireless turned off because it lives inside the server cabinet next to a lot of other sensitive networking stuff. If you happened to read my wireless security diatribe a couple of week ago, you'll recall a mention of how Virgin (my other ISP) tells you that your new cable hub has wireless enabled, including for a free open "guest network" connection. But you can turn it all off.

So you won't be surprised to hear that the BT hub has the same, but they don't tell you. When I originally placed the order, I'd been careful to verify with the sales guy that wireless could be completely disabled in their hub, and was told it could. What soon became clear is that you can turn off your own "primary" and "guest" networks, but you can't turn off the public open (and unsecured) "BT Wi-Fi" wireless network feature. There's absolutely no capability to configure it. It's on all the time, whether you agree to that or not.

I suppose it would have been a good opportunity to experiment to see how the free open Wi-Fi system worked, whether it used the same IP address as "my" connection, and whether it actually could eat up all my bandwidth. As I still have the hub (BT might decide they want it back sometime), I guess that's a task for a rainy day when I run out of other jobs.

Instead, as you'll see later, I simply tagged in a Netgear router that has an RJ45 Ethernet port for cable connections and can handle PPPoE. But that was only after some rather tortuous conversations with a guy at our local electronics store, and a search of the web for a wiring plan. All initiated by the fact that my existing ADSL modem/router can do both PPPoA (ordinary PPP over ADSL) and PPPoE (PPP over Ethernet). So, in theory, there's no reason that it can't be used with a PPPoE modem.

Or so you'd think. The BT cable modem has an RJ45 Ethernet output socket, but the old ADSL modem has an RJ11 "telephone-style" input port. No problem - I can (according to Amazon and several other online stores) buy, or make up myself, an RJ45 to RJ11 interconnect cable. Though figuring the pin connections from the many different diagrams on the web looked less than simple. So I popped down to the local electronics store and asked if they had one. I have to say that I wasn't prepared for the half-hour spirited discussion that ensued, and I'm still not sure which parts were accurate.

According to the expert man I talked with, after you switch to "Infinity" the ADSL port on your modem is redundant. You cannot use it at all, for anything. Therefore, you cannot buy an RJ45 to RJ11 connector - there is no such thing. Even if there was, it wouldn't work. Yet, according to BT, you can use your existing ADSL modem as long as it supports PPPoE, can expose a network username and password, and can be configured with an MTU of 1492. All of which my existing modem can.

In fact, the load-balancing router on my network, next down the line from the modem, can do PPPoE. It has an Ethernet input port, and I confirmed that it worked fine plugged into the BT Infinity cable modem. I could have just used that setup, but I wanted a perimeter network (what we're no longer allowed to call a DMZ) with port forwarding to a web server, so I needed a separate hub/router between the cable modem and the load-balancing router.

In the end I decided to replace the several-years old ADSL modem with one that has Gigabyte connections (not that I'm actually going to reach the limits of a 100 MB port), and where the firmware is a bit more up to date. And, of course, has an RJ45 Ethernet input port. But I also bought an RJ45 to RJ11 cable from Amazon - at some point I'm going to find out whether this would have worked. Maybe you already tried this, or can tell me whether it's a realistic option before I break something experimenting.

Best of all, however, the purchase of a new modem/router means I have another ADSL router to add to my growing collection of spare ones...