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Rayhaan JaufeerallyandClaude Fable 5.1 2910a2a800 slides: light theme, final edits, single-file bundle

As presented. The palette is light on request of the reviewer; code blocks
and byte dumps keep a dark ground so the byte colours still work. The OPEN
walk lights the hovered bytes as an inverted block and its table cells are
dark text on a tint of their group colour.

build.py inlines reveal.js, the stylesheets, scripts and Markdown sections
into slides/dist/hands-on-bgp.html for uploading.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

2026-10-01 20:40:55 +02:00

The lab

bgplab.rayhaan.net

Notes: Section 5. What the students are about to touch, and what stands between a typo and the Internet.

What you are connected to

Notes: The lab speaker is a small BGP daemon written for this course; it runs on the same machine as the router. Both dashed hops are real BGP sessions. Everything to the right of pr01 is the actual Internet.

Your prefix

2a0d:d741:<n>::/48

<n> is your number in hex: student 10 is 2a0d:d741:a::/48
Put your name in owner: only the owner can withdraw a route
One prefix each

Notes: Put the URL and the class password on the board. The page is a snapshot by default; turn on auto-refresh at the top right to watch things change.

What happens when you press Announce

The lab speaker builds an UPDATE. Click bytes to see it, hover to decode it
pr01 checks it against its import filter
pr01 decides, per neighbour, whether to pass it on
Your announcement propagates throughout the whole internet!
ping 2a0d:d741:<n>::1 answers, from anywhere

Notes: Step 5: pr01 answers for every address in the lab space, so reachability of your prefix depends only on whether your announcement got out.

Steering your route

You add	Who acts	Effect
nothing		announced everywhere
`210036:0:0`	pr01	announced nowhere
`210036:0:0` `210036:1:42476`	pr01	only to the SwissIX route servers
+ `42476:0:0` `42476:1:559`	SwissIX	…and from there only to SWITCH
`NO_EXPORT`	pr01	accepted, never passed on

Same idea at two hops: never there, only there, nowhere.

Notes: 210036:0: never to that AS, 210036:1: to that AS, 210036:2/3: the same by exchange (1 SwissIX, 2 NL-ix, 3 France-IX, 4 DE-CIX). A "never" always wins. The preset menu next to the field has all of these.

Handout Part 2 & 3

Notes: Looking glasses: bgp.tools, RIPEstat, and the exchange's own. Global visibility takes a minute or two to settle after each change.

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