Bufferbloat, The Internet, And How To Fix It

There’s a dreaded disease that’s plagued Internet Service Providers for years. OK, there’s probably several diseases, but today we’re talking about bufferbloat. What it is, how to test for it, and finally what you can do about it. Oh, and a huge shout-out to all the folks working on this problem. Many programmers and engineers, like Vint Cerf, Dave Taht, Jim Gettys, and many more have cracked this nut for our collective benefit.

When your computer sends a TCP/IP packet to another host on the Internet, that packet routes through your computer, through the network card, through a switch, through your router, through an ISP modem, through a couple ISP routers, and then finally through some very large routers on its way to the datacenter. Or maybe through that convoluted chain of devices in reverse, to arrive at another desktop. It’s amazing that the whole thing works at all, really. Each of those hops represents another place for things to go wrong. And if something really goes wrong, you know it right away. Pages suddenly won’t load. Your VoIP calls get cut off, or have drop-outs. It’s pretty easy to spot a broken connection, even if finding and fixing it isn’t so trivial.

That’s an obvious problem. What if you have a non-obvious problem? Sites load, but just a little slower than it seems like they used to. You know how to use a command line, so you try a ping test. Huh, 15.0 ms off to Google.com. Let it run for a hundred packets, and essentially no packet loss. But something’s just not right. When someone else is streaming a movie, or a machine is pushing a backup up to a remote server, it all falls apart. That’s bufferbloat, and it’s actually really easy to do a simple test to detect it. Run a speed test, and run a ping test while your connection is being saturated. If your latency under load goes through the roof, you likely have bufferbloat. There are even a few of the big speed test sites that now offer bufferbloat tests. But first, some history. Continue reading “Bufferbloat, The Internet, And How To Fix It”

Low-Level Academy Gets Into Details

We often say that you don’t have to know how an engine works to drive a car, but you can bet that every driver at the Indy 500 knows exactly how it works. You could say the same for computers. You don’t need to understand the details, but it really helps, especially if something goes wrong. [Low-Level Academy] has an online class where you can program in Rust inside your browser to learn about low-level TCP and UDP networking details.

Just how low it goes, we aren’t exactly sure, yet. There are three of eight modules ready to go. The first three cover number encoding, exchanging messages with UDP, and fragmentation. Reliability, routing, server programming, TCP, and HTTP are not out yet, but the ultimate project is a web server. In addition, new modules are released to sponsors first, so the fragmentation module for example won’t be available for a few more days. While that seems unorthodox, it is no different than having to wait for an HBO show to show up on basic cable in reruns.

Continue reading “Low-Level Academy Gets Into Details”