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This is the archive for all posts from 2019.

A new beginning

It's time for something new: after three years as a network architect at Logius, I'm going back into business for myself.

I'm going to focus on providing advice about connectivity to the internet to organizations for which an internet connection is a critical asset.

Watch this space for more information!

Permalink - posted 2019-02-28

Een nieuw begin

Het is tijd voor een nieuwe uitdaging: na drie jaar als netwerkarchitect bij Logius begin ik vanaf 1 maart weer voor mezelf.

Hierbij richt ik me op het adviseren over connectiviteit naar het internet aan organisaties waarvoor een internetverbinding een kritisch bedrijfsmiddel is.

Hou deze plek in de gaten voor meer informatie!

Permalink - posted 2019-02-28

How elastic is your network traffic?

How much bandwidth do I need? Always a hard question. It gets harder as you use more network links, and have to start considering what happens when one or more links fail, leaving you with reduced bandwidth.

The simple way to determine how much total bandwidth you need is to make a guess, and then adjust until the peaks in your bandwidth graphs stay below the 100% line. The more complex answer is that it depends on the bandwidth elasticity of the applications that generate your network traffic.

Applications are bandwidth elastic (sometimes known as "TCP friendly") when they adapt how much data they send to available bandwidth. They're inelastic when they keep sending the same amount of data even though the network can't handle that amount of data. Let's look at a few examples in more detail.

I'm assuming the bandwidth need throughout the day shown in this graph:

Between 21:00 and 22:00, normal bandwidth use reaches a peak of just over 80% of available capacity. But now we lose 25% of our bandwidth, so we have a higher bandwidth need than we can accommodate between 18:00 - 19:00 and 20:00 - 22:00, shown in red below:

Let's look at the behavior of applications with different bandwidth elasticity.

Read the article - posted 2019-03-18

Dark mode!

Last year Apple introduced dark mode in MacOS. This is really nice at night because your eyeballs aren't blasted with tons of white backgrounds in pretty much all windows. Unfortunately, most web pages still use a white background. Obviously you can redesign your website to conform to dark mode, but this looks rather stark on computers in light mode.

The solution would be to have your website render dark on a system in dark mode and light on a system in light mode. As of the new version of Safari included in MacOS 10.14.4 Mojave that was released just now, you can actually do that, as you can see here. Just switch your system between light and dark mode and you'll see this webpage switch over accordingly.

I like to use this terminal command to switch between light and dark mode:

sleep 2; osascript -e 'tell application "System Events" to tell appearance preferences to set dark mode to not dark mode'

(Change the last "not dark mode" to "true" or "false" to enable or disable dark mode. The line above toggles back and forth.)

On your website you need to set up conditional CSS with media queries. This is what I use:

<style type="text/css" media="screen, print">
  body { background-color: #f0f0f0; }
  A { color: #c00000; text-decoration: underline; }
  A:visited { color: #700000; text-decoration: underline; }
  H1 { font-family: futura, arial, sans-serif; font-size: 14pt; }
</style>
<style type="text/css" media="screen and (prefers-color-scheme: dark)">
  body { background-color: #202020; color: #d0d0d0; }
  A { color: #ff6734; }
  A:visited { color: #d82000; }
</style>

The first part between sets everything up for light mode, with a very light gray background.

Then the second style section (in bold) with (prefers-color-scheme: dark) overrides those earlier color settings. Note that all the font settings from the first style section are inherited by the second style section; no need to restate all of those.

That's it! Pretty cool, right?

Update: have a look here for more information, including how to use dark mode with javascript.

Permalink - posted 2019-03-26

Dubbele regenboog!

Image link - posted 2019-04-25

→ πŸ‡ͺπŸ‡Ί Ja, er valt echt iets te kiezen bij de verkiezingen voor het Europees Parlement

Morgen zijn de verkiezingen voor de Nederlandse afgevaardigden naar het Europees Parlement. Ik had half-en-half het plan om hier een stukje te schrijven over wat nu de relatie is tussen de Nederlandse partijen en de Europese fracties waar zij deel van uitmaken. Maar: Stuk Rood Vlees heeft dit veel beter gedaan dan ik kon!

Absolute aanrader om deze blogpost te lezen.

De echte uitslagen komen pas zondagavond om 23 u nadat de stembussen de alle overige landen ook gesloten zijn, maar naar verwachting zal er donderdagavond wel een exitpoll zijn en wat uitslagen van individuele stembureaus.

Ik ben ook erg benieuwd naar de Britse uitslagen en de consequenties die met name de Tories hieraan zullen verbinden voor de brexit.

Read the article - posted 2019-05-22

→ Happy Birthday BGP

Geoff Huston has written a post on the APNIC blog congratulating BGP with its 30th birthday. BGP version 1 was published as RFC 1105 in June of 1989. Five years later, the BGP version 4 was published as RFC 1654. And we're still using BGP-4 today, 25 years later! Lots of things, including IPv6 support, were added later in backward compatible ways.

As usual, Geoff's story is comprehensive with lots of interesting details. For instance:

❝From time to time we see proposals to use geo-based addressing schemes and gain aggregation efficiencies through routing these geo-summaries rather than fine-grained prefixes.❞

Sorry about that. πŸ˜€ I still think it could work, though.

Well worth a read.

Read the article - posted 2019-06-10

Let's fix those BGP route leaks

Last week, there was a large route leak that involved Swiss hosting company Safe Host and China Telecom. The route leak made internet traffic for European telecoms operators KPN, Swisscom and Bouygues Telecom, among others, flow through Safe Host and China Telecom against the wishes of the telecom operators involved. See this Ars Technica story for more details.

In this post, I'm going to explain how the interaction between the technical and business aspects of internet routing have made this issue so difficult to fix. At the end I'll briefly describe a proposal that I think can actually make that happen.

Read the article - posted 2019-06-13

Path validation with RPKI draft

Last week, I suggested it's time fix those BGP route leaks. I live by the words everybody complains about the weather, but nobody does anything about it, so as such I wrote an Internet-Draft with the protocol changes necessary:

draft-van-beijnum-sidrops-pathrpki-00

I think we can stop these route leaks with a relatively modest change to RPKI: by combining the ASes the origin trusts and the ASes the operator of an RPKI relying party server trusts, we have a list of all the ASes that may legitimately appear in the AS path as seen from this particular vantage point.

Read the article - posted 2019-06-20

Be gone, AS_SETs!

As I was writing my RPKI path validation draft last week, I considered the issue of filtering BGP AS paths with AS_SETs in them.

Turns out that I'm not the only one who feels AS_SETs are unnecessary: there's an RFC saying the exact same thing: RFC 6472.

Read the article - posted 2019-06-24

112-storing: hoe voorkomen we zulke problemen op het internet?

Afgelopen maandagmiddag was er een grote storing in het telefonienetwerk van KPN, waarbij ondermeer het alarmnummer 112 zo'n drie uur niet bereikbaar was. Hoe kan het dat een telefoontje op een vaste lijn van KPN naar een meldkamer in de veiligheidsregio Groningen last heeft van dezelfde storing als een telefoontje van een Vodafone-gebruiker naar een meldkamer in de veiligheidsregio Limburg-Zuid? Dinsdag kwam het antwoord: een softwarefout. Het mocht niet baten dat het betreffende systeem viervoudig uitgevoerd was.

Intelligent network

In de telefonie is al vele jaren geleden het zogenaamde intelligent network ingevoerd. Voor die tijd waren vaste nummers gekoppeld aan wijkcentrales en mobiele nummers aan de mobiele operator. Als je dus van de ene kant van de stad naar de andere verhuisde, of van de ene mobiele operator naar de andere, dan kreeg je een nieuw nummer. Met IN was dat niet meer nodig: de telefooncentrale vraag aan een centrale database waar telefoontjes naartoe gerouteerd moeten worden. Probleem is wel dat het telefoonnetwerk nu afhankelijk is van een klein aantal centrale systemen. (En Voice over IP (VoIP) heeft dat versterkt.) Voorheen kon je nog binnen je eigen stadsdeel bellen zolang de wijkcentrale het deed, ook al lag de rest van het telefoonnetwerk plat.

Internetrouters worden afhankelijk van centrale systemen

We zien nu dezelfde ontwikkeling op ons af komen in de internetwereld. (...)

Read the article - posted 2019-06-25

→ Kan een 112-achtige uitvalstoring ook het internet treffen?

Een iets aangepaste versie van mijn post 112-storing: hoe voorkomen we zulke problemen op het internet? van eerder deze week staat nu op Netkwesties. Klik de link om het daar te lezen.

Read the article - posted 2019-06-27

→ Als het internet een hartaanval krijgt

Interessant: de NRC schrijft over BGP en route leaks. Ben benieuwd of dit elders opgepikt gaat worden.

Read the article - posted 2019-07-12

4K TV part 1: what you need to know about the hardware

Although it says "4K TV", as far as I know, there's (virtually) no actual TV broadcast in 4K, so what I'm really talking about here is the state of home theater technology as of around 2018. This post is about the hardware and the formats. Part 2 will be about 4K content and whether the 4K thing is worth the money.

Read the article - posted 2019-08-22

4K TV part 2: 4K and Dolby Atmos content

So with all the technical details out of the way in part 1, let's have a look at where to get 4K content and whether it's worth the trouble and the expense. Where I've found 4K content...

Read the article - posted 2019-08-26

You can never have too many BGP books

Image link - posted 2019-09-09

IPv4 to run out in Europe before the end of the year

Seven years ago, the RIPE NCC, which serves Europe, the middle east and the former Soviet Union, was no longer able to give out IPv4 address space to ISPs and other networks as needed. From that point on, the "last /8" policy came into effect, which meant that each "RIPE member" or local internet registry (LIR) could get one last IPv4 /22 (block of 1024 addresses). It very much looks like that last bit of IPv4 address space will run out before the end of the year.

Right before the final /8 policy came into effect, the RIPE NCC was giving out about a million IPv4 addresses per week. In 2019, they gave out a million IPv4 addresses every three months in the form of those final /22s. And now it's a million IPv4 addresses every six weeks, with two million left to go. Apparently, many new LIRs are set up to get one of those /22s while they last.

latest version of this image on the RIPE website

So in all likelihood RIPE will move from the final /8 policy to a new policy, where LIRs are put on a waiting list and get a /24 as those become available, before the end of 2019.

Permalink - posted 2019-09-09

Securing BGP: we can do it!

In this month's edition of The ISP Column Why is Securing BGP just so Damn Hard? Geoff Huston asks himself exactly this question. He lists ten reasons. I don't agree with most of them: this is a solvable problem.

Read the article - posted 2019-09-20

Kilmaatmars Den Haag

Image link - posted 2019-09-30

Fotolog is terug

Van 2007 tot 2016 postte ik regelmatig foto's hier op muada.com. Een deel van die foto's zijn verloren gegaan bij de overgang naar een nieuwe server. Ik heb nu een groot aantal weer terug kunnen zetten en ook de foto-upload-functionaliteit verbeterd, zodat ik vanaf nu weer makkelijk snel een foto op deze site kan plaatsen.

Nog een tip: ik heb de foto's de volgende CSS-stijl gegeven:

max-width: 100vw; max-height: 92vh;

Door de units (honderdsten van) viewport width (vw) en viewport hight (vh) te gebruiken gebruiken de foto's maximaal de volle breedte en 92% van de hoogte van het scherm.

Hier is het foto-archief van 2019 met links naar de archieven van eerdere jaren. 2015 en 2016 missen alleen nog foto's, en in 2017 en 2018 heb ik helemaal geen losse foto's op de site gezet.

Permalink - posted 2019-09-30

Routing theory: are link state and distance vector the only games in town?

During his talk about 30 years of BGP, Geoff Huston said something along the lines of "someone should come up with another type of routing protocol besides distance vector and link state". That is of course too delicious a challenge to ignore...

Read the article - posted 2019-10-15

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