Category: Internet

It’s incredible how many people assume that The Internet is a thing. In reality, it’s a mishmash of interconnected independent operators running mostly on goodwill, misplaced trust in other people’s competence, and (sometimes) pure dumb luck.

I described a few consequences of this sad reality in the Internet Has More than One Administrator video (part of How Networks Really Work webinar), and Nick Buraglio and Elisa Jasinska provided even more details in their Surviving the Internet Default-Free Zone webinar.

As I explained in How Networks Really Work and Upcoming Internet Challenges webinars, routing security, and BGP security in particular remain one of the unsolved challenges we’ve been facing for decades (see also: what makes BGP a hot mess).

Fortunately, due to enormous efforts of a few persistent individuals BGP RPKI is getting traction (NTT just went all-in), and Flavio Luciani and Tiziano Tofoni decided to do their part creating an excellent in-depth document describing BGP RPKI theory and configuration on Cisco- and Juniper routers.

There are only two things you have to do:

• Read the document;
• Implement RPKI in your network.

Thank you, the Internet will be grateful.

After my response to the BGP is a hot mess topic, Corey Quinn graciously invited me to discuss BGP issues on his podcast. It took us a long while to set it up, but we eventually got there… and the results were published last week. Hope you’ll enjoy our chat.

In October 2019, Donald Sharp did a short webinar describing FRRouting, the hottest open-source routing suite.

As always, he started with an overview of what FRRouting is, and where you could use it.

The Facts and Fiction: BGP Is a Hot Mess blog post generated tons of responses, including a thoughtful tweet from Laura Alonso:

Is your argument that the technology works as designed and any issues with it are a people problem?

A polite question like that deserves more than 280-character reply, but I tried to do my best:

BGP definitely works even better than designed. Is that good enough? Probably, and we could politely argue about that… but the root cause of most of the problems we see today (and people love to yammer about) is not the protocol or how it was designed but how sloppily it’s used.

Laura somewhat disagreed with my way of handling the issue:

A friend of mine sent me a short message including…

There is a number of products that recently arrived or are coming to market using group encryption systems for IP networks, but are (understandably) not using IPsec.

… which triggered an old itch of mine caused by the “We don’t need no IETF standards, code is king” stupidity.

A while ago Johannes Weber tweeted about an interesting challenge:

We want to advertise our AS and PI space over a single ISP connection. How would a setup look like with 2 Cisco routers, using them for hardware redundancy? Is this possible with only 1 neighboring to the ISP?

Hmm, so you have one cable and two router ports that you want to connect to that cable. There’s something wrong with this picture ;)

In Never-Ending Story of IP Fragmentation I described how you could use TCP Maximum Segment Size to minimize the impact of IP fragmentation and PMTUD blackholes (more details on TCP MSS clamping)… but one has to wonder how people use TCP MSS in the wild and what values you might see.

As is often the case, Geoff Houston found a way to measure them, and published the answer: TCP MSS Values

The last bits of updated Never-Ending Story of IP Fragmentation were published a few days ago: IP fragmentation and tunnels and summary and related blog posts, RFCs and other articles.

Every now and then I stumble upon a blog post saying “OSI 7-layer model sucks” or “OSI 7-layer model is a lie”, most recent one coming from Robert Graham.

Before going into the details, let’s agree on the fundamentals.

Most everyone who ever tried to build a network spanning more than one transmission technology and including intermediate nodes came to the conclusion that layered approach to networking makes sense.

Whether you have three, four, five, or seven layers in your model doesn’t matter. What really matters is that your model contains all the functionality you need to implement host-to-host networking in target environment.