About Me

When not at work with students, I spend my time in my room either reading, calculating something using pen and paper, or using a computer. I read almost anything: from the pornographic to the profound, although my main interests are mathematics and physics. "When I get a little money I buy books; and if any is left I buy food and clothes." -Erasmus

Tuesday, October 9, 2012

Fixing the home network

I wasted one whole afternoon and one evening fixing my home network.

Although there are only two people here, we have three computers (four if you count my phone) that may sometimes need to connect to the internet at the same time. The usual dsl service that PLDT provides (for plan 999, at least) is good only for a modem without wifi. (As for the speed, PLDT should be ashamed! And they dare to call it DSL service?) To fix this, my younger brother set up a wireless router from CDRKing, and for a time, this was perfectly satisfactory.

I've had the annoyance of suddenly disconnecting from the net and then seeing the modem restart on its own.  So I did some tests. I connected a computer directly to the modem, and I noticed that there were times that my computer couldn't obtain an IP address from the modem. The way we handled it was just to restart the modem and then hope for the best. Although it was annoying to restart the modem every once in a while, we lived with it because I was too busy doing something else, while my Mom knew nothing about how to set it up.

One day, though, our router decided to quit. After inspecting it, I noticed that the power supply was busted; there was a crack near the male plug, and presumably, replacing the power adapter should fix the problem. But because I didn't have a second adapter, I couldn't test if that was the only thing wrong with the router.

Since I had to fix the router or get a replacement, I set up the modem at my room and connected my computer directly to it. I stayed up all night and stayed online to check if I had modem to computer connectivity issues, and also to search online for possible solutions to the busted router. I discovered that my computer suddenly gets disconnected from the modem for no reason (pinging the modem gives no response), and presumably some of the connectivity issues we had with the router could be traced to the sudden inability of the modem and router to talk to each other.

One analogy that I've found useful is to think of the DSLAM, the modem, and the router as substations of a postal service. To view a website, your computer sends a message to the router, then the router sends this message to the modem and, then the modem sends it to the DSLAM. The DSLAM sends it further on until it reaches the server hosting the website, but if there's a problem here, then it's PLDT's responsibility or the server's responsibility. Then the server sends the return message or data that allows you to view the webpage along the reverse path. The lights on the modem and the router, as well as pinging various websites, and the router could be used to trace where the connectivity problem might be.

For example, if you ping the router's IP address, and you get no response (even though the icon on your computer says you're connected wirelessly) could mean that the postal service at the router level is down. Since we have three computers, by trying all three, we can easily eliminate the possibility that there's something wrong with the computer service that sends and receives messages (packets is the technical term) to a router or a modem.

Checking the router to modem connection is tricky, and the best way to check is to just connect your computer directly to the modem. If your computer is able to obtain an IP address from the modem and view websites, but you can't get an IP address or view a  website when you're connected through the router, then there might be something wrong with the router.

Other checks are based on the postal service analogy, and any break in deliveries between two directly connected substations will result in having no internet connection. So the task of someone who oversees the network is to find where along the delivery path a failure happens, and then fix it.

Now if we go back to my problem, one task is to fix the connectivity issue between modem and router/computer. Restarting the modem more often than not gave me the limited or no connectivity icon on my taskbar, and doing ipconfig on the command line gave me the dreaded 169.xxx.xxx.xxx IP address) The modem  we use is a Zyxel P660-R-D1, and we've already had it replaced twice. I was sure it was already out of warranty, so I didn't want to call a PLDT tech and then have him come over, say that the modem needs to be replaced, and then bill us for another PhP 1K. Besides, the last time one came over, he didn't even try to upgrade the modem firmware (this is the program that manages the various tasks of the modem), so it just might be a software issue.

So during one of the modem's sober moments, (after more than a few restarts!), I was able to go online and I downloaded the PLDT version of the firmware (ZyNOS firmware version V.3.40(APG.4)b4; although another version of the firmware was available, I didn't get it, choosing instead to stay with PLDT firmware ) and then uploaded it into the modem. After doing so, I tested it again, by restarting the modem to see if I could finally connect, and if the connection was stable. For now, it looks like the firmware upgrade fixed that problem. I could connect to the modem, access the firmware, all without worrying about modem to computer connectivity. Without the router, everything worked fine.

After connecting the router, I encountered another problem: only one computer at a time could connect to the net. Unfortunately, I was dumb enough to do a factory reset on both modem and router, so I had problems connecting to the rest of the net. Fortunately, I could access the net using my cellphone, and I could look up the correct modem and router setup.  But some of it involved a lot of trial and error because I did not know what all the settings meant. I set up the modem as the DHCP server, set the router on bridge mode, disabled the DHCP server function in the router. If I understand it correctly, the modem assigns IP addresses to the computers connected to the router, and I had the ability to access the modem firmware without having to disconnect the router.  Getting all that done wasted the afternoon and the evening as well.

One gripe that I have is: why in hell doesn't PLDT have a handy website that contains some of the technical stuff that I need? The firmware, for example, should have been on a PLDT website. For comparison, the telco formerly known as Qwest (they're just a subsidiary now) had a website containing the modem firmware. I've also looked at Verizon's website, and it's a lot more informative than PLDT's website. (This link, for example, gives instructions on how to reset one modem brand that they support. If you navigate through their website, you can even find supporting information on each modem and a few routers , as well as information on home networking. )

But then, of course, if it were up to PLDT, they'd rather tell me that if I want more than  one computer connected to the net, I should "upgrade" and get their more expensive plan, and then get the modem with wifi capabilities. They'd rather provide bad customer service and have people pay for stuff that they don't need. After all, in many places, if you want DSL service, they still have a monopoly; they have no reason for improving service because they need not fear any competition.

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