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.

Long story short: it’s time for another summer break, as people reporting my bloopers – THANK YOU!!! – know only too well. I plan to be back in early autumn rolling out tons of new content.

I’ll do my best to reply to support requests (it will take longer than usual), and probably won’t be able to resist publishing a few lightweight netlab-related blog posts. If you get bored there’s still over 400 hours of existing content, over 100 podcast episodes, and thousands of blog posts.

An anonymous commenter asked this highly relevant question about my Internet routing security lab:

What are the smallest hardware requirements to run the lab?

TL&DR: 2 GB RAM, 2 vCPU

Now for the more precise answer (aka “it depends”).

After I published the Source IP Address in Multicast Packets blog post, Erik Auerswald sent me several examples of network devices sending IP packets with source IP address set to 0.0.0.0:

• Cisco wireless access points using 0.0.0.0 as the source IP address in VRRP packets.
• Extreme (formerly Avaya) switches sending IGMP queries with source IP address 0.0.0.0 on VLANs on which they have no IP address.

I created a netlab topology you can use to practice BGP security tools I described in the Internet Routing Security webinar:

• The lab topology mirrors the sample topology I described in the Classification of BGP Route Leaks (RFC 7908) blog post with one router per autonomous system
• BGP is configured on all devices, and EBGP sessions are set up between all directly-connected devices.

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.

Andrei Robachevsky asked me to spread the word about the new MANRS+ customer survey:

MANRS is conducting a survey for organizations that contract connectivity providers to learn more about if and how routing security fits into their broader supply chain security strategy. If this is your organization, or if it is your customers, we welcome you to take or share the survey at https://www.surveymonkey.com/r/BDCWKNS

I hope you immediately clicked on the link and completed the survey. If you’re still here wondering what’s going on, here’s some more information from Andrei:

Years ago I wrote an article describing how EIGRP stub routers work and how you should use them in redundant remote sites to make sure link- or node failures don’t result in partial connectivity. That article is now available on ipSpace.net; I hope at least someone will find it useful. I know it’s about ancient technology, but then people are still running COBOL on mainframes.

While preparing the Internet Routing Security webinar, I stumbled upon RFC 7908, containing an excellent taxonomy of BGP route leaks. I never checked whether it covers every possible scenario¹, but I found it a handy resource when organizing my thoughts.

Let’s walk through the various leak types the authors identified using the following sample topology: