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Cable Modem Adventures
By Thiravudh Khoman

For the record, yours truly is now soaring with the eagles. Translation: I just got a cable modem. Not from Asianet/UBC, mind you, because as I write this, I'm in the U.S. Here in my particular locale, cable modem service is provided by AT&T; Broadband and the service is called "@Home" (https://www.athome.att.com).

Need or Want?

I don't mind admitting that I've thought getting a faster internet connection for some time now. In Thailand, things still seem to be stuck in the "testing" phase, and despite the frequent PR, questions as to when it will become widely available and how much it will cost still remain up in the air. Here in the U.S., higher speed internet options have almost become mainstream, and while they're still not available everywhere, they do tend to be available in most major cities.

But whether I needed it or just had this unbridled lust for speed was the topic of an ongoing debate I've had with myself for a while now. In truth, if I could have obtained a free internet service at a decent speed (say 50kbps), I probably would NOT have gotten a cable modem - or at least would have procrastinated on the decision a bit longer in order to save costs.

Getting free internet access is pretty easy in the U.S. now, although there tend to be strings attached (e.g. on-screen ads). But that's not really a major problem for me, since there are ways to minimize the ads, and furthermore, my wife can dial into her university account and access the internet for free without the hassles of ads (which sort of means I can too!).

My problem was more about getting a decent connection. For some inexplicable reason, I can only get at best, a 26.4kbps connection when I dial into the internet. Despite test dialing from three locations in the city, trying two different computers, two different modems, and a half dozen ISP's, I was still stuck in a 22-26 kbps rut (half of what I'm used to in Bangkok with a Telecom Asia line). Knowledgeable locals are unanimous that the phone lines in this city "suck" and that if I wanted better, I had no choice but to get DSL or a cable modem.

(Note: Bangkok'ers don't realize how lucky they are - they can actually choose their local phone service provider (i.e. TOT or TA). Although long distance phone service has been liberalized in the U.S., local phone service is still very much a monopoly. Don't like your local service provider? Tough, or buy a cell phone!.)

But 26.4kbps in and of itself isn't all THAT bad (especially given the fact that I started modeming at 300 bps!). While it practically eliminates any meaningful downloading, web browsing and email checking are bearable with a bit of patience. But what I truly can't stand is that I get disconnected very frequently. In fact, when I tried to set up an appointment to have cable installed via AT&T;'s website, I got disconnected midstream and was forced to place a voice call in order to find out whether my appointment and other data I had entered were complete (they weren't!). This, more than anything else, took me to the edge of getting a cable modem.

What pushed me over the edge was a special offer from AT&T; for 6 months of @Home service for US$19.95 per month (reduced from the normal US$39.95). Do the math, and you'll see that that's cheaper than the pervasive monolith, America Online, and most ISP accounts in Thailand. And you get cable! With such an offer, all resistance and/or uncertainties crumbled.


Was cable modem the only alternative open to me? Technically speaking it wasn't. Currently, there are three fast internet technologies in popular use:

  1. Satellite: Here, you buy a satellite dish which can be used for both subscription TV and internet access. The biggest problem with this solution is that it only provides downstream data transfers (i.e. data RECEIVED by you). For upstream transfers (i.e. data SENT by you) you will need to connect to an ISP via a regular dial-up line. Yuck! Double yuck! There are a LOT of things I don't like about this technology: a) the capital investment, especially given that I wasn't going to be in the U.S. for very long, b) the problems of placing/positioning the dish re: the open sky, c) the downstream/upstream kludge, and d) the need to deal with multiple vendors. Frankly, I never seriously considered this option.

  2. DSL: While DSL ("Digital Subscriber Line") is available in the city I'm in, it's not available in the neighborhood I live in. My guess is that the poor telephone lines make DSL impossible in this area. Either that or it's located too far away from the telephone center. But even if it were a viable alternative, I'm not sure if I would have opted for it anyway. One reason is that you need to deal with (and pay) two entities: a) your ISP and b) the phone company. Still, the advantage of DSL is that there are no drops in speeds because the line is not shared; but on the other hand, its theoretical speed is lower than cable.

  3. Cable Modem: Based on the above, it should be obvious that I didn't really have much of a choice. But chances are, I would have chosen this option anyway, especially since I already had AT&T; cable TV. My only concern was how bad the speed drop-off would be during peak periods. Cable modems, unlike DSL, do NOT operate on a dedicated line; rather, the bandwidth is pooled. During peak hours when lots of people are using their cable TV or accessing the internet through cable, the speed will drop. I'll discuss this a bit more when I present some benchmarks later.

Hardware Configuration

Let's talk hardware. If you've only ever used a standalone computer, then the cable modem setup is going to be a bit tricky, and chances are you will require some additional hardware (a network card, an Ethernet hub, some LAN cabling, etc.). Fortunately, the cable company will/may provide this and do all the setup for you. If, however, you're used to setting up local area networks and/or have the requisite hardware (as in my case), then setup is pretty simple.

Fortunately, the apartment I'm living in is already wired for cable, and as mentioned, I already had cable TV (from the same company, AT&T;, to boot). Theoretically, you don't need to subscribe to cable TV to subscribe to cable-borne internet service, but it usually makes things a lot less messy.

Here's what my cable and computer setups looked like BEFORE the cable modem was installed:

    Cable outlet      A/C outlet      A/C outlet   Telephone outlet
    +----------+      +--------+      +--------+   +--------------+
       |                 |  |             | |             |
  Coax |             A/C |  | A/C         | | A/C         | RJ-11
       |   +-------------+  |             | |             |
       |   |                |             | |             |
   +-----------+ Coax  +------+      +----------+         |
   | Cable box |-------|  TV  |      | Computer |         |
   +-----------+       +------+      | w/modem  |---------+

(Note: The two A/C lines running out of the computer are for the computer and the monitor. Also, the standard, 2-wire RJ-11 telephone cable is connected to the internal modem.)

This is a common, run-of-the-mill cable setup. A UBC cable TV setup in Thailand should look very similar if not identical. Now, here's what it looks like AFTER the cable modem was installed:

   Cable outlet               A/C outlet               A/C outlet
   +----------+               +--------+               +--------+  
        |              A/C      |    |       A/C          | |
        | Coax            +-----+    +------+             | | A/C
        |                 |                 |             | |
   +----------+       +-------+       +----------+    +----------+
   | Splitter |       | Cable |       | Ethernet |    | Computer |
   +----------+       | Modem |       |    Hub   |    | w/NIC    |
      |   |           +-------+       +----------+    +----------+
      |   |             |   |            |    |            |
      |   +-------------+   +------------+    +------------+
 Coax |         Coax              CAT 5             CAT 5   
  +-----------+      +------+
  | Cable box |------|  TV  |
  +-----------+ Coax +------+
      |                  |
  A/C |  +---------------+ A/C
      |  |
   A/C outlet 

What's happened here is that the signal from the cable outlet was split using a splitter, and a cable modem and an Ethernet hub were inserted in between the cable outlet and the computer, which now sports a network card (i.e. a "NIC"). In other words, the internet feed is now being provided via the cable outlet rather than the telephone outlet.

(Note: While I haven't tried it yet, my guess is that you can directly wire the cable modem to the computer using an RJ-45 crossover cable. Or if the cable modem and the computer's NIC had thin Ethernet connectors (mine don't), you could connect them that way as well. This saves you from having to buy an Ethernet hub. Also, since the cable modem runs at 10 megabits, having a 100 megabit hub and NIC's won't be terribly helpful.)

Software Configuration

Again, if you're used to setting up local area networks (especially TCP/IP ones), setting up the cable modem isn't too difficult. First of all, TCP/IP must be bound to the NIC and the computer must be given a specific computer name. For most @Home installations, TCP/IP is setup to dynamically obtain an IP address from @Home's DHCP server. But with certain computers (e.g. mine) a static setup was necessary. Thus, information such as the machine's IP address, DNS server, gateways, default domain, etc. had to be entered. But don't worry - the cable guy does all this!

My computer is running Windows 98, but I was told that you could set this up for Linux machines as well; in fact, any computer that runs TCP/IP, since the @Home service is a standard TCP/IP app.

Certain software caveats bear some discussion:

  1. First, even though @Home can be configured to use a DHCP server, you still get assigned a fixed, unchanging IP address. Apparently, the DHCP server is used only because it simplifies setup. Having a fixed IP address, though, makes you more vulnerable since people can always guess or find out what this IP address is and launch attacks directly at you or track you more easily. Conversely, having a fixed IP address also makes it easier for people to interact with you on a more benign basis. For example, they can point their chat program directly at your IP address without having to go through an intermediary server.
  2. Second, Windows users should make absolutely certain that "file and print sharing" is disabled under TCP/IP. Please read that sentence again. It's okay to use "file and print sharing" under some other protocol such as NetBEUI, but if you leave it on for TCP/IP, people on the internet may be able to see and possibly manipulate your files and printers. By manipulate, I mean delete or edit your files or upload unpleasant freebies to your system.
  3. Third, because you have a fixed IP address and because most people leave their cable modems on all the time, it's an awfully good idea to run some kind of firewall software on your computer (I even do this with dial-up). I'm currently trying out Norton Personal Firewall from Symantec (https://www.symantec.com) but there are other good programs out there as well, notably BlackIce Defender from Network Ice (https://www.networkice.com) and ZoneAlarm from Zone Labs (https://www.zonelabs.com), the latter being free for personal use. Please get one.


@Home's default web browser is Internet Explorer v5.x with a custom "skin". I don't use this much, preferring my regular trio of browsers (Opera, Netscape and regular IE), all of which work just fine. Other apps that I've tried include Eudora Pro and WS_FTP. This is rather limited, I admit, but then this is all that I use. I have no reason to believe that other internet apps wouldn't work though.

One interesting thing I've noticed is that as a default, the @Home browser (and therefore, IE) is set to use a proxy server. While this is normal in Thailand in order to save bandwidth, I was a bit surprised to find it here - the first I've seen with a U.S. ISP - especially given the fact that line congestion isn't much of a concern with cable modems.

Before I forget, @Home provides subscribers with 10mb of web space and 7 email addresses. While mildly generous, I didn't need it anyhow since I already have my own web and mail servers. More important to me was the fact that I could use @Home's SMTP server to send my [email protected] mail, which speeds things up for me. As a general rule, most (but not all) subscription ISP's allow the use of their SMTP servers, while very few free ISP's do.

How Fast?

No doubt, the biggest question on everyone's mind is: "Exactly how fast is the cable modem?" As I mentioned earlier, cable modems are susceptible to fluctuating speeds because they share bandwidth with other users (unlike DSL). Simply put, during peak periods, the speed will drop, while during low-usage periods, the speed will soar.

Theoretically, the top speed of cable modems is 10 megabits per second, assuming the cable ISP doesn't put an artifcial "cap" on this (@Home supposedly doesn't, but some do so that users don't experience such large speed swings). In real life, though, you will never get 10 Mb/sec - you probably won't even come CLOSE to that. I've been running benchmarks at various times of the day for the past few days and the very best speed I've seen is 2.55 Mb/sec, while the worst I've measured is 355 Kb/sec. (Note: I got my benchmarks from: https://www.computingcentral.com/topics/bandwidth/speedtest.asp.) As a general rule, I expect to get about 1.5 Mb/sec during non-peak hours and about 700 Kb/sec during peak hours.

While this is a welcome relief from the 26.4 Kbps I've been getting with my regular modem, these speed swings are bound to aggravate some people who expect a "fast" link to be "fast" all the time. This may be true for DSL, but it's not for cable modems. In my case, I can accept these limitations, and in fact they're no different from what I have to do when I'm in Thailand; i.e. I have to pick and choose a non-peak time to download large files. The cable modem has simply increased the size of files that I can download during peak periods without having to wait too long a time.

(Such speed swings are hardly unusual. Even on a hard-wired, local area network, you WON'T be running at the maximum rated speed, unless perhaps you're the sole user on the LAN. With a 10 megabit LAN, you can expect to run at half that speed or less during operational hours.)

On the other hand, the speed of web browsing and email checking have shown less obvious improvements. Granted, they're both faster - especially for U.S. based sites - but not nearly as pronounced as they are with file downloading. If you have a mailbox with your dial-up ISP in Thailand, mail checking with a 56K modem in Thailand feels only marginally slower than checking mail in the U.S. with a cable modem. Meanwhile, Napster'ing has shown much less improvement than I had expected. I tried downloading some music files using Napster (purely for testing purposes, NATURALLY, of songs that I already owned, NATURALLY) and my impression is that the speed improvement is only moderately faster than downloading from Thailand with a 56K modem. Granted, this may be due to my limited expertise in using Napster effectively.

Let's talk about real numbers for a change. The first night I got my cable modem, I downloaded about 400+mb worth of files (I already had a Linux wishlist in hand). One 180mb file in particular, took less than 30 minutes to download (that was past midnight). While this can be used as a measure of what's possible, it shouldn't be used as a goal to be achieved every time, since download speeds can and do vary depending on a LOT of factors. And oh, by the way, cable modem downloads CAN get aborted as with dial-up connections, so a download utility with "resume" capabilities is still recommended for time-consuming downloads. Despite these caveats, 100mb downloads are no longer a pipe-dream for me, and I can even download entire Linux distributions (100's of Mb's) if I really wanted.

One final note on "speed". Folks who are used to dialing every time they need to access the internet will enjoy the "always on" nature of cable modems. While it is possible to turn off a cable modem (as with an external modem), I understand most people tend to leave it on 24 hours/day. Every time you turn on your computer (assuming you turn it off!), Windows or your operating system of choice, will try and logon you onto "the network", with the cable modem acting as a "bridge" to the non-local portions of your network (i.e. the internet). The advantage of this type of networking as opposed to "dial-up networking" is that there are no busy signals and therefore, no undue delays in getting "on".

Of course, people who already access the internet from a local area network at their workplaces will find this benefit to be "old hat" (I'm part of this group, I'm afraid). While I dial-up at home, at work, I've set up a LAN-based internet sharing box which always appears to be "on", so I'm used to this (yawn!). But for those people who have never experienced this convenience, they'll find that it speeds up as well improves their internet'ing immeasurably.

How Fast in Thailand?

All in all, my cable modeming experiences with @Home have been quite positive. But would a cable modem (or DSL for that matter) in Thailand be equally satisfactory? Unfortunately, I suspect not. The speed benefits I'm receiving are due to the fact that I'm relatively close (speed- and distance-wise) to the servers that I access. This will not be the case in Thailand unless your desired content is locally hosted. If much of your target content is overseas (a reasonable assumption), all accesses will have to swim through your ISP's international gateways. These are MUCH slower than the high speed U.S. backbone that I have pass through to reach my desired servers.

In other words, while a cable modem will increase the speed of the link between your computer and your ISP, it DOES NOT and CANNOT increase the speed of the international links. This assumption is easy enough to verify by running the scenario in reverse; i.e. by checking how fast I can browse Thailand websites or check mail from Thailand mail servers. Despite my cable modem, displaying Thai web pages or checking mail from Thailand isn't all that different from accessing U.S. web pages or checking mail from a U.S. mail server while in Thailand, with a 56K modem.

My guess is that until the bandwidth of the international gateways are doubled, tripled or even quadrupled, I believe the benefits of a cable modem in Thailand will be limited if your intended content is NOT Thailand-based.

Copyright © 2000, Thiravudh Khoman