BGP Code Dive (2)

Now that you have a copy of BGP in Go on your machine—it’s tempting to jump right in to asking the code questions, but it’s important to get a sense of how things are structured. In essence, you need to build a mental map of how the functionality of the protocol you already know is related to specific files and structure, so you can start in the right place when finding out how things work. Interacting with an implementation from the initial stages of process bringup, building data structures, and the like isn’t all that profitable. Rather, asking questions of the code is an iterative/interactive process.

Take what you know, form an impression of where you might look to find the answer to a particular question, and, in the process of finding the answer, learn more about the protocol, which will help you find answers more quickly in the future.

So let’s poke around the directory structure a little, think about how BGP works, and think about what might be where. To begin, what might we call the basic functions of BGP? Let me take a shot at a list (if you see things you think should be on here, Continue reading

So you want to be a better network engineer? …

Then you need to read the book Daniel Dib and I just published on LeanPub. It’s called Unintended Features.. From the Introduction:

So you’ve decided you want to be a network engineer—or you’re already you a network engineer, and you want to be a better engineer, to rise to the top, to be among the best, to… Well, you get the idea. The question is, how do you get from where you are now to where you want to be? This short volume is designed to answer just that question. If you’re expecting a book on technology, then you’re in the wrong place. Instead, this is a book about how to build a career in networking technology, including topics such engineering culture, being intentional about your education, thinking skills, and some basic skills you’ll want to develop.

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Worth Reading: Live streaming to 800,000 users

Fewer companies know how to build world spanning distributed services than there are countries with nuclear weapons. Facebook is one of those companies and Facebook Live, Facebook’s new live video streaming product, is one one of those services. -High Scalability

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Independence Day 2016

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Unintended Features

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Worth Reading: Alchemy can’t save Moore’s Law

We don’t have a Moore’s Law problem so much as we have a materials science or alchemy problem. If you believe in materials science, what seems abundantly clear in listening to so many discussions about the end of scale for chip manufacturing processes is that, for whatever reason, the industry as a whole has not done enough investing to discover the new materials that will allow us to enhance or move beyond CMOS chip technology. -The Next Platform

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Book – Unintended Features

Hi everyone,

I have some exciting news to share with you. I’ve been working on a book lately together with Russ White. It’s called Unintended Features – Thoughts on thinking and life as a network engineer. The book is partly based on blog post we have written in the past but also some unique content for the book. The outline of the book is as follows:

So you’ve decided you want to be a network engineer—or you’re already you a network engineer, and you want to be a better engineer, to rise to the top, to be among the best, to… Well, you get the idea. The question is, how do you get from where you are now to where you want to be? This short volume is designed to answer just that question.

This book tries to teach concepts not found in other writings such as thinking more about architecture and seeing patterns in technology and how to stay current in the networking industry. With the rapid pace of the networking industry it seems like we are sipping from the fire hose. How can we prevent this? Isn’t every new technology pretty much an old one with some new Continue reading

Worth Reading: Open season

Let’s once more look at this topic again, and start with what we mean by the term “Open Internet.” The expression builds upon a rich pedigree of the term “open” in various contexts. It gives the impression that “open” is some positive attribute, and when we use the expression of the “open Internet”, it seems that we’re lauding it in some way. But are we, and if so, in what way? -CircleID

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Worth Reading: Independence from L2 data centers

We’ve all been there. That “non-disruptive” maintenance window that should “only be a blip”. You sit down at the terminal at 10pm expecting that adding a new server to the MLAG domain or upgrading a single switch will be a simple process, only to lose the rack of dual-attached servers and spend the rest of your Thursday night frantically trying to bring the cluster back online. If I never spend another evening troubleshooting an outage caused by MLAG, I’ll die happy! -Cumulus

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Launch

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Worth Reading: Fishing for a cure to DDoS attacks

There is no way you can equate the importance of the Internet to a vital source of daily nutrients for billions of people. Yet the Internet is no doubt a critical ingredient of modern society. And it’s far from being “overfished.” In fact, the Internet is exploding with promising new use cases. Sadly, the Internet is also exploding with menace. -Data Center Journal

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Worth Reading: APNIC’s cyber threat intellegence

Security automation and cyber threat intelligence can play a significant role by filtering out the noise floor created by unsophisticated and untargeted threats, providing insight to the evolution of sophisticated adversary tradecraft, and validating defensive security and response measures. -APNIC

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Split Tunnel Insecurities

I really dislike corporate VPNs that don’t allow split tunneling—disconnecting from the VPN to print on a local printer, or access a local network attached drive, puts a real crimp in productivity. In the case of services reachable over both IPv6 and IPv4, particularly if the IPv6 path is preferred, split tunneling can be quite dangerous, as explained in RFC7359. Let’s use the network below to illustrate.

In this network, host A is communicating with server B through a VPN, terminated by the VPN concentrator marked as “VPN.” Assume the host is reachable on both 192.0.2.1 and 2001:fb8:0:1::1. The host, the upstream router, the network in the cloud, and the server are all IPv6 reachable. When the host first connects, it will attempt both the IPv6 and IPv4 connections, and choose to use the IPv6 connection (this is what most current operating systems will do).

The problem is: the VPN connection doesn’t support IPv6 at all—it only supports IPv4. Because IPv6 is preferred, the traffic between the host and the server will take the local IPv6 connection, which is not encrypted—the blue dash/dot line—rather than the encrypted IPv4 tunnel—the red dashed line. The user, host, and Continue reading

Worth Reading: The great DevOps train wreck

Well, I see one coming, and I’m raising the alarm. Based on the conversations I’m hearing, it’s becoming dangerously fashionable to say: “All the interesting technology problems in DevOps are solved. We have Docker. We have Kubernetes. We have OpenStack. They’re stable, and they’re widely deployed. All that’s left to do is process transformation, teaching dullard enterprise IT teams how to consume the new-new IT.” -The New Stack

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Worth Reading: Aggregation pixies

What if we could magically fix de-aggregation in IPv4 address space that was handed out in needs-based chunks? You can visualise the magic fix for this being “prefix pixies”, that, every night, when we’re asleep and the Inter-tubes only carry trickles of IP packets, they go around every BGP speaker on the global Internet, and they swap addresses. -APNIC

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Overvaluing Experience

“Sure, great candidate—so long as you just look at the paper. They don’t have any experience.”

I wonder how many times I’ve heard this in my networking career—I wonder how many times this has been said about me, in fact, after I’ve walked out of an interview room. We all know the tale of the paper tigers. And we all know how hard it is to land a position without experience, and how hard it is to get experience without landing a job (I have a friend in just this position right now, in fact). But let me tell you a story…

I don’t fish any longer, but I used to fish quite a bit—with my Grandfather. Now, like most Grandfathers, mine was not ordinary. He was, in fact, a County Agent, working for the US Forestry Service. This meant he spent his time blasting ponds, helping farmers figure out how to increase yield on their fields, and growing all sort of odd new types of things on his small plot of land. He also had mules (I’ll tell you about the mules some time later, I’m certain), and an old Forestry Green pickup truck.

Anyway, to return to Continue reading

Worth Reading: How to be an open source good citizen

Let me start by saying that no company can truly “own” an open source project. When the decision is made to open source a project, it should be understood that the code truly is being “shared” with a larger community outside of your company’s walls. That community now “owns” the project. You may be part of it; you may even be its biggest contributor and its current custodian. But it is no longer yours, and with time, you may become a minority stakeholder. Even if you decide to discontinue using an open sourced project internally and no longer contribute to it, it does not mean that the project has come to an end. -The New Stack

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Worth Reading: Doing nothing on EMP

Imagine you’re driving down the interstate, and suddenly, your car comes to a halt. You pick up your cell phone to call a family member for help, but you don’t have service. Then, when you look up, you see that all vehicles are also stopped. It’s 96 degrees out so you decide to walk to the nearest gas station to grab a bottled water only to find that your debit card has been rendered useless. -Townhall

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BGP Code Dive (1)

I often tell network engineers they need to learn to code—and they sometimes take my advice and run off to buy a book, or start an online program (which reminds me, I’m way, way behind in my own studies about right now). But learning to code, and being able to use that skill for anything are actually two different things. In fact, my major problem with my coding skills is finding projects I can undertake where I don’t feel like I’m wasting my time. Anyone want to write the world’s 25 millionth implementation of inserting the date and time into a document? No, I didn’t really think so.

So what can you do with coding skills? One thing you can do is <em?read the source. Thus, I’m starting an entirely new feature here at ‘net Work. Every now and again (which means I don’t know how often), I’m going to poke at some routing or control plane code or another, and try to figure out what it actually does. Why not just go through a single protocol line by line? Because—honestly—it’s not a useful way to approach a protocol in code. Rather—here is my first bit of advice—you want Continue reading

Worth Reading: Net Neutrality as a good start

Within the net neutrality arrangements, the incumbent operators will now have to treat their broadband businesses in exactly the same way as, in the past, they had to provide other telecoms services such as telephony. In other words, they can’t discriminate by giving preference to their own content service, or on the basis of others paying them premium prices for premium services aimed at favouring certain services over others. -CircleID

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