Peak Time

So lately our cable broadband has been getting really slow in the evenings, starting around 6pm. In the morning it flies (18mb download speeds according to DSL Reports speed test), but come prime time, pages won’t load, valid addresses are not found, form submits time out — we’re talking narrowband stuff here, like a 28.8 modem from 1994. We don’t have anything better to do in the evenings than surf the Internet (except when we’re at the Arthur Murray or Dance North County) so this is kind of annoying.

Yesterday we had three (count ’em) techs from the cable company out looking at it for like two and a half hours. They were here so long that we served them Auntie’s cookies and milk for dinner. (Thanks for the cookies, Auntie.) By the time they were ready to give up it was after 9pm. (One of them wanted to stay and talk a little more about my Linux machine, but his colleagues dragged him away. Evidently they had homes to go to.)

End result: Signal strength — fine. Line integrity — fine. Splitters in the wall — rigged up by Dr. Frankenstein. They kindly fixed that (cookie bribe worked), but it didn’t improve the situation any. A supervisor will be coming to follow up, and I will try to explain my theory in hopes that he will be a network guy who will understand what I’m talking about.


See, cable bandwidth is shared, and if somebody hogs it, everyone else will suffer. Ethernet is a contention-based networking scheme, which means that you basically send your request (packet) out onto the wire and then wait to see what happens. Generally this will be one of the three things: The packet reaches its destination; somebody else puts a packet onto the wire at roughly the same time you do, the packets collide, and you both have to re-send; or the packet just disappears into the Ether. If Joe Downloader has a fire hose hooked up to your network segment, then there are going to be a lot of collisions, and eventually your poor Ethernet network interface card (NIC) will just give up. DSL is less susceptible to this out in the neighborhood; bandwidth isn’t shared until you get out onto the provider’s trunk, which probably has a heck of a lot more capacity than the lines in your neck of the woods.


This is part of the reason why Comcast, which has been widely vilified (and now sued) for interfering with peer-to-peer and other forms of traffic, is getting support from some quarters. I’m not in favor of Comcast’s practices, which I find shady, especially when a company advertises “unlimited” broadband. If you can’t handle the traffic, upgrade your equipment, or else accurately represent what services you can offer.

Anyway, based on the evidence and an informal survey of neighbors who are experiencing the same problem (sample size 1), I am pretty convinced that what we’re looking at is a network saturation issue — i.e., someone is coming home, firing up their machine, and flooding the copper with packets. Here are my top suspects:

  • Neighborhood kid downloading vast quantities of porn
  • Neighborhood kid downloading vast quantities of illegal MP3s
  • Neighborhood kid downloading copies of movies that haven’t even been released in theaters yet
  • Neighborhood kid attempting to destabilize small countries in Asia, just for fun
  • Neighborhood kid playing “XBox Live” with 4,927 of his or her closest friends
  • Neighborhood zombie Windows machines spewing vast quantities of spam
  • Television networks attempting to bring down the Web to force people to watch crappy reality shows instead
  • Too many people trying to read my blog, causing global Internet slowdowns
  • SkyNet preparing to take over the world

Of course, that last one is just ridiculous. Why, if SkyNet were getting ready to take over the world, the first thing it would do is eliminate anyone who might try to spread the alarm, and I’ve been doing that for yea

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