Episode Details

Links Referenced

• ThousandEyes
• The Duckbill Group
• Last Week in AWS
• Screaming in the Cloud
• AWS Morning Brief

Transcript

UDP. I'd make a joke about it, but I'm not sure you'd get it. 

This episode is sponsored by ThousandEyes. Think of ThousandEyes as the Google Maps of the internet. Just like you wouldn't dare leave San Jose to drive to San Francisco without checking if 101 or 280 was faster and yes, that's a very localized reference to San Francisco Bay area. Businesses rely on ThousandEyes to see the end to end paths their apps and services are taking from their servers to their end users to identify where the slowdowns are, where the pileups are hiding and what's causing the issues. They use ThousandEyes to see what's breaking where and importantly, they share that data directly with the offending service providers to hold them accountable and get them to fix the issue fast, ideally before it impacts end users. You'll be hearing a fair bit more about ThousandEyes over the next 12 weeks because Thursdays are now devoted to networking in the cloud. It's like screaming in the cloud, only far angrier.

We begin today with the first of 12 episodes. Episode one, the fundamentals of cloud networking. You can consider this the AWS morning brief networking edition. So a common perception in the world of cloud today is that networking doesn't matter, and that perception is largely accurate. You don't have to be a network engineer the way that any reasonable systems or operations person did even 10 years ago, because in the cloud, the network doesn't matter at all until suddenly it does at the worst possible time, and then everyone's left scratching their heads.

So let's begin with how networking works, because a computer in 2019 is pretty useless if it can't talk to other computers somehow. And for better or worse, Bluetooth isn't really enough to get the job done. Computers talk to one another over networks, basically by having a unique identifier. Generally, we call those IP addresses here in the path that this future has taken. In a different world, we would've gone with token ring and a whole bunch of other addressing protocols, but we didn't. Instead we went with IP, the unimaginatively named internet protocol, and with the current version of the internet protocol, version four, we're not talking about IPv6 because let's not kid ourselves, no one's really using that at scale despite everyone claiming that it's going to happen real soon now.

So there are roughly 4 billion IP addresses and change, and those are allocated throughout effectively the entire internet. When this stuff was built back when it was just defense institutions and universities on the internet, 4 billion seemed like stupendous overkill. Now it turns out that some people have 4 billion objects on their person that are talking to the internet and all chirping and distracting them at the same time when you're attempting to have a conversation with them.

So those networks are broken down into subnetworks or subnets, for lack of a better term. And they can range anywhere from a single IP address, which in CIDR, C-I-D-R parlance is a /32 to all 4 billion and change, which is a /0. Some common ones tend to be /24, which is 256 IP addresses, of which 254 are usable and you can expand that into 512 with a /23 and so on and so forth. The specific math isn't particularly interesting or important and it's super hard to describe without some kind of whiteboard. So smile, nod and move past tha