Category: worth reading

Talking about BGP routing policy mechanisms is nice, but it’s even better to see how real Internet Service Providers use those tools to implement real-life BGP routing policy.

Getting that information is incredibly hard as everyone considers their setup a secret sauce. Fortunately, there are a few exceptions; Pim van Pelt described the BGP Routing Policy of IPng Networks in great details. The article is even more interesting as he’s using Bird2 configuration language that looks almost like a programming language (as compared to the ancient route-maps used by vendors focused on “industry-standard” CLI).

Have fun!

More than thirteen years after I started creating vendor-neutral webinars, it’s time for another change¹: the ipSpace.net subscriptions became perpetual. If you have an active ipSpace.net subscription, it will stay valid indefinitely² (and I’ll stop nagging you with renewal notices).

Wow, Free Lunch?

Sadly, that’s not the case.

Bruce Davie published an interesting overview article about Large Language Models. It would be worth reading just for the copious links to in-depth article; I particularly like his conclusions:

We mistake performance (producing realistic text) for competence (understanding the world).

Having a model for language is different from having a model of the world.

And that’s a perfect explanation why it makes no sense to expect ChatGPT and friends to produce picture-perfect device configurations or always-working code.

Anne Baretta found a great video describing the October 2018 GitHub failure. Here’s the TL&DW:

• The failure was caused by a short (~ 1 minute) disconnect of the primary data center
• The database replicas failed over to the secondary data center, but that failover was never tested and of course some stuff didn’t work.
• In the meantime, batch jobs modified data in the primary data center, making the two replicas out-of-sync.
• It took them over 24 hours to clean up the mess.

One of my readers asked for my opinion about the following masterpiece posted on (where else) LinkedIn¹:

More than a dozen years after the SDN brouhaha erupted, some people still haven’t got the memo on the obsolescence of CLI. For example, Julia Evans tries to make people comfortable with the command line. Has nobody told her it’s like teaching COBOL?

On a more serious note: you OUGHT TO master Linux CLI and be comfortable using CLI commands on network devices and servers. Her article has tons of useful tips and is definitely worth reading.

Sharada Yeluri (Senior Director of Engineering at Juniper Networks) wrote a long article describing the connectivity requirements of AI workloads and new approaches to Ethernet fabrics. Definitely worth reading if you’re interested in these topics.

Gerben Wierda published a nice description of common reactions to new unicorn-dust-based technologies:

• Eyes that glaze over
• Eyes like saucers
• Eyes that narrow

He uses generative AI as an example to explain why it might be a bad idea that people in the first two categories make strategic decisions, but of course nothing ever stops people desperately believing in vendor fairy tales, including long-distance vMotion, SDN or intent-based networking.

Bruce Davie collected numerous articles describing various aspects of early Internet history and pre-Internet days, including A Brief History of the Internet and The Design Philosophy of the DARPA Internet Protocols.

Have fun ;)

Emile Aben is describing an interesting behavior observed in the Wild West of the global Internet: someone started announcing BGP paths with an unknown attribute, which (regardless of RFC 7606) triggered some BGP session resets.

One would have hoped we learned something from the August 2010 incident (supposedly caused by a friend of mine 😜), but it looks like some things never change. For more details, watch the Network Security Fallacies and Internet Routing Security webinar.

On the Communications of the ACM web site, Bertrand Meyer argues that (contrary to the exploding hype) AI Does Not Help Programmers:

As a programmer, I know where to go to solve a problem. But I am fallible; I would love to have an assistant who keeps me in check, alerting me to pitfalls and correcting me when I err. A effective pair-programmer. But that is not what I get. Instead, I have the equivalent of a cocky graduate student, smart and widely read, also polite and quick to apologize, but thoroughly, invariably, sloppy and unreliable. I have little use for such supposed help.

Not surprisingly, my experience is pretty close to what he’s describing. AI is the way to go if you want something that looks reasonable (at a first glance), but not if you want to get something right. Unfortunately, there’s a bit of a difference between marketing and engineering: networks that are configured 90% correctly sometimes fail to do what you expect them to do.

Found an interesting article describing the shenanigans of a biotech startup. Admittedly, it has nothing to do with networking apart from the closing paragraph…

But people will find all sorts of ways to believe what they want to believe, to avoid hearing things that they don’t want to hear, and to avoid thinking about things that are too worrisome to contemplate.

… which is a perfect description of why people believe in centralized control planes, flow-based forwarding, or long-distance vMotion.

Julia Evans published another phenomenal blog post, this time focused on blogging myths including:

• You need to be original
• You need to be an expert
• Posts need to be 100% correct
• Writing boring posts is bad
• You need to explain every concept
• Page views matter
• More material is always better

Dip Singh published an excellent primer on communication fundamentals including:

• Waves: frequency, amplitude, wavelength, phase
• Composite signals, frequency domain and Fourier transform
• Bandwidth, fundamental and harmonic frequency
• Decibels in a nutshell
• Transmission impairments: attenuation, distortion, noise
• Principles of modern communications: Nyquist theorem, Shannon’s law, bit and baud rate
• Line encoding techniques, quadrature methods (including QPSK and QAM)

Even if you don’t care about layer-1 technologies you MUST read it to get at least a basic appreciation of why stuff you’re using to read this blog post works.

Brandon Hitzel published a detailed document describing various Internet WAN edge designs. Definitely worth reading and bookmarking.