Saturday, September 20, 2014

Network issues solved: replaced D-link DIR-810L by ASUS RT-N66U

Streaming video to our computers, or even audio, was problematic at our house. It had been some months (don't remember how many months exactly), but we had these other issues too:
  • ssh to my ISP's shell server, and after a few minutes, response would become glacial. I mean, type "ls" and it's literally minutes. If I did it right after login, it was fine; it was only after a few minutes it would act constipated.
  • downloads of any size took "forever". We tried to download a map upgrade so the lovely Carol could update her GPS; eventually I wrote a script to kill the download and restart it (fortunately it could pick up from where it left off). It wasn't as straightforward as "wget -c", because we started the download by clicking on some icon, then hitting some button and… (I hate computers.)

    Fortunately, by saying "ps wwx" or something like this I was able to get the program's parameters. The script I wrote involved monitoring the most recently updated file in the most recently updated directory (many files were getting downloaded, with a new directory getting created every so often), then killing and restarting the download process when it looked like things had paused for more than a minute or two.

We have DSL and are supposed to be able to get something like 5-6 Mbits per second. And we often have; we watch streamed video on netflix without problems. So that puzzled me.

On another occasion, Sheri wanted to download a 200-Mbyte package; it never finished. I thought it was the wireless, so I ran a long cable to her computer—not much better. I got the URL and just said "wget" on my own computer, something like this:

collin@p3:/mnt/home/collin> wget -O frsxprodmg
--2014-08-26 21:58:03--
Resolving (,,, ...
Connecting to (||:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 218103808 (208M) [application/x-apple-diskimage]
Saving to: `frsxprodmg'

21% [=======>                               ] 47,504,787   624K/s  eta 4m 36s  ^C^Cc^C^C^C^Z
It sat there, paused, for quite a while. Then, as you can see, I got frustrated and hit some keys to stop it. I then restarted.
collin@p3:/mnt/home/collin> wget -c -O frsxprodmg
--2014-08-26 22:00:18--
Resolving (,,, ...
Connecting to (||:443... connected.
HTTP request sent, awaiting response... 206 PARTIAL CONTENT
Length: 218103808 (208M), 170541677 (163M) remaining [application/x-apple-diskimage]
Saving to: `frsxprodmg'

41% [++++++++=======>                       ] 90,094,310   393K/s  eta 4m 37s  ^C
It hung after another, what, 43 million bytes? I restarted it a few more times, getting varying amounts of data in before the download hung. I was very thankful for "wget -c" but even with that, the experience wasn't pleasant. 18MB, 65MB, 2MB, then about 43MB to finish.

Now I will pause here to remember that we live in an astounding age, where in less than half an hour, we can download something like 200 Mbytes of software and be quite confident that the data were not corrupted during transmission. That said, with all this technology it's supposed to be easier.

It was about at this time that I remembered the issues I'd been having with my ssh (login) sessions to my ISP. Could all this be caused by the router? I asked my ISP's support folks.

They confirmed that yes, this behavior could be caused by a flaky router. In my case it was a D-link DIR-810L, which we've had since October.

They suggested I try without the router. Ooooh, OK, so I logged in as root and unmounted all the NFS. Turned off as many services (xinetd, sshd, etc.) as I could figure out easily, changed the network configuration for DHCP, and connected it directly to the DSL modem (disconnecting the rest of the home network).

But I couldn't connect to anything--had to route add default gw with an "educated" (yeah right) guess. I hate computers.

Once I figured that out, I ran wget and… you guessed it—the entire 207MB+ came down in one shot, about five minutes So it was the old router!

After asking some folks at work, I went shopping. The recommended Buffalo item wasn't available locally, but I was looking for the ASUS RT-N66U dual-band wireless-N900 router. Best Buy (near Home Depot!) had an RT-N66R, but I didn't know what the difference was between 'R' and 'U' so was skittish.

I ended up ordering it from amazon and using "amazon locker" for delivery. This worked quite well. The idea is, rather than having to run over to the UPS office ("What are your hours again?"), I can have it delivered to a nearby 7-11 (open 24 hours a day). emails me a secret code, which I key into the locker thingie, and one of the dozens of doors pops open; inside is my item.

So I got it home and hooked it up. Configuration was a breeze, even though I have a somewhat unusual configuration (default gateway is, not .1.1). The router automagically downloaded a firmware upgrade (this operation went quite quickly, which made me feel confident in my purchase). I then tried the 207MB download, and it came in under five minutes. Whee!

Icing on the cake: logins to the server don't go all molasses-in-January-in-Minnesota on me after a few minutes.

One more thing: I naïvely set the SSIDs to the same thing on both the 5GHz and 2.4GHz wireless networks. This seemed to confuse the macbook air's wireless. (Was it cycling between the two networks, which btw also shared the same password?) After I separated the SSIDs, the problem went away.

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