slides: no step-by-step reveals; UPDATE example is 2a0d:d740::/48 at SwissIX

- Removed every fragment and stepped code highlight: a slide now shows
  everything at once. Two code blocks keep a static highlight on one line.
- Dropped "What stands between you and an outage".
- The UPDATE walked through in section 3 is now 2a0d:d740::/48 as AS210036
  announces it to the SwissIX route servers: next hop 2001:7f8:24::c9
  (pr01's port on the peering LAN), AS path 210036, MED 0 and 210036:10:2,
  matching what pr01's export filter puts on routes to peers. Encoded with
  the packet crate and parsed back to the identical message; the slide
  generator asserted every quoted number, including the next hop, against
  the bytes. Adds a MULTI_EXIT_DISC slide to the walkthrough.

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

slides/README.md

@@ -19,10 +19,18 @@ chain of nodes and links, an AS path.
 | IP transit and Internet exchanges | `sections/04-transit-and-ix.md` |
 | The lab: ferrix, pr01.rue and its exchanges | `sections/05-lab.md` |
 
-The UPDATE in section 3 is a real one captured from ferrix. Its byte slides
+The UPDATE in section 3 is `2a0d:d740::/48` as AS210036 announces it to the
-step through it one part at a time (press down); every number on them was
+SwissIX route servers: next hop `2001:7f8:24::c9` (pr01's port on the peering
-checked against the capture when the slides were generated. If you replace the
+LAN), MED 0 and the `210036:10:2` tag, which is what pr01's export filter puts
-capture, regenerate rather than edit the hex by hand.
+on routes to peers. It was produced with ferrix's own encoder and parsed back
+to the same message, not captured off the wire; a capture from pr01 may differ
+in detail (BIRD can append a link-local next hop). The byte slides step through
+it one part at a time (press down), and every number on them was checked
+against the bytes when the slides were generated. To change the example,
+regenerate rather than edit the hex by hand.
+
+The deck deliberately has no fragments or stepped code: a slide shows
+everything at once. Two code blocks keep a static highlight on one line.
 
 | File | Holds |
 |---|---|
@@ -75,8 +83,6 @@ Apply a class to the element above with `<!-- .element: class="..." -->`.
 
 | Class | Effect |
 |---|---|
-| `fragment` | appears on the next click |
-| `fragment pop` | appears, grows and takes the accent colour |
 | `big` | one large statement on the slide |
 | `note` | quiet italic aside |
 | `attribution` | small credit under an image or quote |

slides/sections/01-addresses.md

@@ -29,7 +29,7 @@ Ask: why only once? Because 2a0d::1::1 could put the zeros in several places.
 
 <p class="bits"><span class="fixed">2a0d:d741:0001</span><span class="free">xxxx:xxxx:xxxx:xxxx:xxxx</span></p>
 
-The first <span class="fragment pop">48</span> bits are fixed. The other 80 are yours.
+The first **48** bits are fixed. The other 80 are yours.
 
 Notes:
 2^80 addresses in one student prefix. About 1.2 million billion billion.
@@ -48,7 +48,7 @@ The /n is a count of leading bits, nothing more.
 
 `<n>` is your student number, written *in hex*.
 
-<!-- .element: class="fragment note" -->
+<!-- .element: class="note" -->
 
 Notes:
 Student 10 is 2a0d:d741:a::/48, student 16 is 2a0d:d741:10::/48.
@@ -58,7 +58,7 @@ A /40 holds exactly 256 /48s, which caps the class size at 255.
 
 ## The most specific route wins
 
-```text [1-3|3]
+```text [3]
 2a0d:d740::/29     via  AS210036           the aggregate
 2a0d:d741::/40     via  AS210036           the lab
 2a0d:d741:1::/48   via  AS210036 AS…       student 1   <-- chosen for 2a0d:d741:1::1

slides/sections/02-registries.md

@@ -26,14 +26,14 @@ an RIR, typically an ISP. Our space comes from RIPE NCC via an LIR.
 
 ## AS numbers
 
-* 16 bits at first: `1` to `65535` <!-- .element: class="fragment" -->
+* 16 bits at first: `1` to `65535`
-* 32 bits since RFC 6793: up to `4294967295` <!-- .element: class="fragment" -->
+* 32 bits since RFC 6793: up to `4294967295`
-* Old routers see `AS23456` (AS_TRANS) in place of a big one <!-- .element: class="fragment" -->
+* Old routers see `AS23456` (AS_TRANS) in place of a big one
-* Private use: `64512–65534` and `4200000000–4294967294` <!-- .element: class="fragment" -->
+* Private use: `64512–65534` and `4200000000–4294967294`
 
 The lab daemon is `AS4200000001`. It is stripped before the Internet sees your route.
 
-<!-- .element: class="fragment note" -->
+<!-- .element: class="note" -->
 
 Notes:
 RFC 6996 reserves the private ranges. The upstream router removes the private
@@ -43,7 +43,7 @@ AS from the path, so the origin everybody else sees is AS210036.
 
 ## The RIPE database says who may announce what
 
-```text [1-5|3]
+```text [3]
 route6:         2a0d:d741:1::/48
 descr:          ETHZ Netsec 2026 BGP lab - student 1
 origin:         AS210036

slides/sections/03-bgp-update.md

@@ -7,10 +7,10 @@ Section 3. The aim: by the end, the bytes view on the lab page reads like text.
 
 ## BGP in one slide
 
-* Runs over TCP, port `179`, between neighbours you configure by hand <!-- .element: class="fragment" -->
+* Runs over TCP, port `179`, between neighbours you configure by hand
-* Each side tells the other its best route per prefix <!-- .element: class="fragment" -->
+* Each side tells the other its best route per prefix
-* Only *changes* are sent: no periodic refresh <!-- .element: class="fragment" -->
+* Only *changes* are sent: no periodic refresh
-* If the session drops, every route learned over it is gone <!-- .element: class="fragment" -->
+* If the session drops, every route learned over it is gone
 
 Notes:
 No discovery, no authentication of content, no notion of truth. A neighbour
@@ -29,7 +29,7 @@ says "I can reach X" and you believe it, subject to your filters.
 
 OPEN, OPEN, KEEPALIVE, KEEPALIVE, and then it is all UPDATEs.
 
-<!-- .element: class="fragment note" -->
+<!-- .element: class="note" -->
 
 Notes:
 There is a fifth, ROUTE-REFRESH: "send me everything again, my policy changed".
@@ -51,41 +51,43 @@ One UPDATE carries one set of attributes, and every prefix that shares them.
 
 -----
 
-## A real one: 94 bytes
+## A real one: 89 bytes
 
 <div class="legend"><span class="hh">header</span><span class="hl">lengths</span><span class="ha">path attributes</span><span class="hn">NLRI</span></div>
 
-<pre class="bytes"><span class="hh">ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff</span> <span class="hh">00 5e</span> <span class="hh">02</span> <span class="hl">00 00</span> <span class="hl">00 47</span> <span class="ha">40 01 01 00</span> <span class="ha2">40 02 06 02 01 fa 56 ea 01</span> <span class="ha">80 0e 1c 00 02 01 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 30 2a 0d d7 41 00 01</span> <span class="ha2">c0 20 18 00 03 34 74 00 00 00 00 00 00 00 00 00 03 34 74 00 00 00 01 00 00 a5 ec</span></pre>
+<pre class="bytes"><span class="hh">ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff</span> <span class="hh">00 59</span> <span class="hh">02</span> <span class="hl">00 00</span> <span class="hl">00 42</span> <span class="ha">40 01 01 00</span> <span class="ha2">40 02 06 02 01 00 03 34 74</span> <span class="ha">80 04 04 00 00 00 00</span> <span class="ha2">80 0e 1c 00 02 01 10 20 01 07 f8 00 24 00 00 00 00 00 00 00 00 00 c9 00 30 2a 0d d7 40 00 00</span> <span class="ha">c0 20 0c 00 03 34 74 00 00 00 0a 00 00 00 02</span></pre>
 
-`2a0d:d741:1::/48`, as the lab daemon sent it. The same view is on the lab page under *bytes*.
+`2a0d:d740::/48`, as AS210036 announces it to the SwissIX route servers.
 
 <!-- .element: class="note" -->
 
 Notes:
-Captured from ferrix, not typed. Press down to walk through it part by part.
+Built with the lab daemon's own encoder and checked by parsing it back, with
-Note there is nothing yellow: the NLRI field is empty. Hold that thought.
+the attributes pr01 puts on routes it exports to peers. Press down to walk
+through it part by part. Note there is nothing yellow: the NLRI field is
+empty. Hold that thought.
 
 ---
 
 ## Header
 
-<pre class="bytes focus"><span class="hh on">ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff</span> <span class="hh on">00 5e</span> <span class="hh on">02</span> <span class="hl">00 00</span> <span class="hl">00 47</span> <span class="ha">40 01 01 00</span> <span class="ha2">40 02 06 02 01 fa 56 ea 01</span> <span class="ha">80 0e 1c 00 02 01 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 30 2a 0d d7 41 00 01</span> <span class="ha2">c0 20 18 00 03 34 74 00 00 00 00 00 00 00 00 00 03 34 74 00 00 00 01 00 00 a5 ec</span></pre>
+<pre class="bytes focus"><span class="hh on">ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff</span> <span class="hh on">00 59</span> <span class="hh on">02</span> <span class="hl">00 00</span> <span class="hl">00 42</span> <span class="ha">40 01 01 00</span> <span class="ha2">40 02 06 02 01 00 03 34 74</span> <span class="ha">80 04 04 00 00 00 00</span> <span class="ha2">80 0e 1c 00 02 01 10 20 01 07 f8 00 24 00 00 00 00 00 00 00 00 00 c9 00 30 2a 0d d7 40 00 00</span> <span class="ha">c0 20 0c 00 03 34 74 00 00 00 0a 00 00 00 02</span></pre>
 
-<table class="decode"><tr><td>ff × 16</td><td>marker. Once carried authentication, now just filler to find message boundaries</td></tr><tr><td>00 5e</td><td>length of the whole message: 94 bytes (maximum 4096)</td></tr><tr><td>02</td><td>type 2 = UPDATE</td></tr></table>
+<table class="decode"><tr><td>ff × 16</td><td>marker. Once carried authentication, now just filler to find message boundaries</td></tr><tr><td>00 59</td><td>length of the whole message: 89 bytes (maximum 4096)</td></tr><tr><td>02</td><td>type 2 = UPDATE</td></tr></table>
 
 ---
 
 ## Two lengths
 
-<pre class="bytes focus"><span class="hh">ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff</span> <span class="hh">00 5e</span> <span class="hh">02</span> <span class="hl on">00 00</span> <span class="hl on">00 47</span> <span class="ha">40 01 01 00</span> <span class="ha2">40 02 06 02 01 fa 56 ea 01</span> <span class="ha">80 0e 1c 00 02 01 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 30 2a 0d d7 41 00 01</span> <span class="ha2">c0 20 18 00 03 34 74 00 00 00 00 00 00 00 00 00 03 34 74 00 00 00 01 00 00 a5 ec</span></pre>
+<pre class="bytes focus"><span class="hh">ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff</span> <span class="hh">00 59</span> <span class="hh">02</span> <span class="hl on">00 00</span> <span class="hl on">00 42</span> <span class="ha">40 01 01 00</span> <span class="ha2">40 02 06 02 01 00 03 34 74</span> <span class="ha">80 04 04 00 00 00 00</span> <span class="ha2">80 0e 1c 00 02 01 10 20 01 07 f8 00 24 00 00 00 00 00 00 00 00 00 c9 00 30 2a 0d d7 40 00 00</span> <span class="ha">c0 20 0c 00 03 34 74 00 00 00 0a 00 00 00 02</span></pre>
 
-<table class="decode"><tr><td>00 00</td><td>0 bytes of withdrawn routes: nothing is being taken back</td></tr><tr><td>00 47</td><td>71 bytes of path attributes follow</td></tr><tr><td></td><td>94 − 19 − 2 − 2 − 71 = 0 bytes left over for NLRI</td></tr></table>
+<table class="decode"><tr><td>00 00</td><td>0 bytes of withdrawn routes: nothing is being taken back</td></tr><tr><td>00 42</td><td>66 bytes of path attributes follow</td></tr><tr><td></td><td>89 − 19 − 2 − 2 − 66 = 0 bytes left over for NLRI</td></tr></table>
 
 ---
 
 ## ORIGIN
 
-<pre class="bytes focus"><span class="hh">ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff</span> <span class="hh">00 5e</span> <span class="hh">02</span> <span class="hl">00 00</span> <span class="hl">00 47</span> <span class="ha on">40 01 01 00</span> <span class="ha2">40 02 06 02 01 fa 56 ea 01</span> <span class="ha">80 0e 1c 00 02 01 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 30 2a 0d d7 41 00 01</span> <span class="ha2">c0 20 18 00 03 34 74 00 00 00 00 00 00 00 00 00 03 34 74 00 00 00 01 00 00 a5 ec</span></pre>
+<pre class="bytes focus"><span class="hh">ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff</span> <span class="hh">00 59</span> <span class="hh">02</span> <span class="hl">00 00</span> <span class="hl">00 42</span> <span class="ha on">40 01 01 00</span> <span class="ha2">40 02 06 02 01 00 03 34 74</span> <span class="ha">80 04 04 00 00 00 00</span> <span class="ha2">80 0e 1c 00 02 01 10 20 01 07 f8 00 24 00 00 00 00 00 00 00 00 00 c9 00 30 2a 0d d7 40 00 00</span> <span class="ha">c0 20 0c 00 03 34 74 00 00 00 0a 00 00 00 02</span></pre>
 
 <table class="decode"><tr><td>40</td><td>flags: well-known, transitive</td></tr><tr><td>01</td><td>type 1 = ORIGIN</td></tr><tr><td>01</td><td>1 byte of value</td></tr><tr><td>00</td><td>IGP: the route was originated inside this AS</td></tr></table>
 
@@ -97,37 +99,56 @@ Every attribute is *flags, type, length, value*.
 
 ## AS_PATH
 
-<pre class="bytes focus"><span class="hh">ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff</span> <span class="hh">00 5e</span> <span class="hh">02</span> <span class="hl">00 00</span> <span class="hl">00 47</span> <span class="ha">40 01 01 00</span> <span class="ha2 on">40 02 06 02 01 fa 56 ea 01</span> <span class="ha">80 0e 1c 00 02 01 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 30 2a 0d d7 41 00 01</span> <span class="ha2">c0 20 18 00 03 34 74 00 00 00 00 00 00 00 00 00 03 34 74 00 00 00 01 00 00 a5 ec</span></pre>
+<pre class="bytes focus"><span class="hh">ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff</span> <span class="hh">00 59</span> <span class="hh">02</span> <span class="hl">00 00</span> <span class="hl">00 42</span> <span class="ha">40 01 01 00</span> <span class="ha2 on">40 02 06 02 01 00 03 34 74</span> <span class="ha">80 04 04 00 00 00 00</span> <span class="ha2">80 0e 1c 00 02 01 10 20 01 07 f8 00 24 00 00 00 00 00 00 00 00 00 c9 00 30 2a 0d d7 40 00 00</span> <span class="ha">c0 20 0c 00 03 34 74 00 00 00 0a 00 00 00 02</span></pre>
 
-<table class="decode"><tr><td>40 02 06</td><td>well-known, transitive; type 2; 6 bytes</td></tr><tr><td>02</td><td>an AS_SEQUENCE, order matters</td></tr><tr><td>01</td><td>of 1 AS number</td></tr><tr><td>fa 56 ea 01</td><td>4200000001, the lab daemon. Four bytes each (RFC 6793)</td></tr></table>
+<table class="decode"><tr><td>40 02 06</td><td>well-known, transitive; type 2; 6 bytes</td></tr><tr><td>02</td><td>an AS_SEQUENCE, order matters</td></tr><tr><td>01</td><td>of 1 AS number</td></tr><tr><td>00 03 34 74</td><td>210036, the origin. Four bytes each (RFC 6793)</td></tr></table>
 
 Each network prepends itself on the way out. The length of this list is what best-path selection compares.
 
 <!-- .element: class="note" -->
 
+Notes:
+One entry, because SwissIX is one hop from the origin and the route server
+does not add itself. Seen from further away it reads e.g. 6939 210036.
+
+---
+
+## MULTI_EXIT_DISC
+
+<pre class="bytes focus"><span class="hh">ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff</span> <span class="hh">00 59</span> <span class="hh">02</span> <span class="hl">00 00</span> <span class="hl">00 42</span> <span class="ha">40 01 01 00</span> <span class="ha2">40 02 06 02 01 00 03 34 74</span> <span class="ha on">80 04 04 00 00 00 00</span> <span class="ha2">80 0e 1c 00 02 01 10 20 01 07 f8 00 24 00 00 00 00 00 00 00 00 00 c9 00 30 2a 0d d7 40 00 00</span> <span class="ha">c0 20 0c 00 03 34 74 00 00 00 0a 00 00 00 02</span></pre>
+
+<table class="decode"><tr><td>80 04 04</td><td>optional, non-transitive; type 4; 4 bytes</td></tr><tr><td>00 00 00 00</td><td>MED 0. Lower is preferred, among routes from the same neighbour AS</td></tr></table>
+
+A hint to a neighbour about which of *your* entrances to use. Non-transitive: it goes one hop and no further.
+
+<!-- .element: class="note" -->
+
 ---
 
 ## MP_REACH_NLRI: where IPv6 lives
 
-<pre class="bytes focus"><span class="hh">ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff</span> <span class="hh">00 5e</span> <span class="hh">02</span> <span class="hl">00 00</span> <span class="hl">00 47</span> <span class="ha">40 01 01 00</span> <span class="ha2">40 02 06 02 01 fa 56 ea 01</span> <span class="ha on">80 0e 1c 00 02 01 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 30 2a 0d d7 41 00 01</span> <span class="ha2">c0 20 18 00 03 34 74 00 00 00 00 00 00 00 00 00 03 34 74 00 00 00 01 00 00 a5 ec</span></pre>
+<pre class="bytes focus"><span class="hh">ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff</span> <span class="hh">00 59</span> <span class="hh">02</span> <span class="hl">00 00</span> <span class="hl">00 42</span> <span class="ha">40 01 01 00</span> <span class="ha2">40 02 06 02 01 00 03 34 74</span> <span class="ha">80 04 04 00 00 00 00</span> <span class="ha2 on">80 0e 1c 00 02 01 10 20 01 07 f8 00 24 00 00 00 00 00 00 00 00 00 c9 00 30 2a 0d d7 40 00 00</span> <span class="ha">c0 20 0c 00 03 34 74 00 00 00 0a 00 00 00 02</span></pre>
 
-<table class="decode"><tr><td>80 0e 1c</td><td>optional, non-transitive; type 14; 28 bytes</td></tr><tr><td>00 02 · 01</td><td>address family IPv6, unicast</td></tr><tr><td>10 · 00…01</td><td>next hop, 16 bytes: ::1</td></tr><tr><td>00</td><td>reserved</td></tr><tr><td>30 · 2a 0d d7 41 00 01</td><td>48 bits of prefix: 2a0d:d741:1::/48</td></tr></table>
+<table class="decode"><tr><td>80 0e 1c</td><td>optional, non-transitive; type 14; 28 bytes</td></tr><tr><td>00 02 · 01</td><td>address family IPv6, unicast</td></tr><tr><td>10 · 2001 07f8 0024 … 00c9</td><td>next hop, 16 bytes: 2001:7f8:24::c9, our port on the SwissIX peering LAN</td></tr><tr><td>00</td><td>reserved</td></tr><tr><td>30 · 2a 0d d7 40 00 00</td><td>48 bits of prefix: 2a0d:d740::/48</td></tr></table>
 
 Notes:
 BGP-4 was built for IPv4: its NLRI field cannot carry anything else. RFC 4760
 bolts other address families on as an attribute, each with its own next hop.
 A prefix is sent as a bit count plus only as many bytes as the count needs.
-The next hop is ::1 because the daemon and the router share a machine.
+The next hop is an address on the exchange's shared LAN: whoever receives this
+route sends packets straight to that address across the switch. Remember ::c9
+for the exchange diagram in the next section.
+Routers may also append their link-local address here, making it 32 bytes.
 
 ---
 
 ## LARGE_COMMUNITIES
 
-<pre class="bytes focus"><span class="hh">ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff</span> <span class="hh">00 5e</span> <span class="hh">02</span> <span class="hl">00 00</span> <span class="hl">00 47</span> <span class="ha">40 01 01 00</span> <span class="ha2">40 02 06 02 01 fa 56 ea 01</span> <span class="ha">80 0e 1c 00 02 01 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 30 2a 0d d7 41 00 01</span> <span class="ha2 on">c0 20 18 00 03 34 74 00 00 00 00 00 00 00 00 00 03 34 74 00 00 00 01 00 00 a5 ec</span></pre>
+<pre class="bytes focus"><span class="hh">ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff</span> <span class="hh">00 59</span> <span class="hh">02</span> <span class="hl">00 00</span> <span class="hl">00 42</span> <span class="ha">40 01 01 00</span> <span class="ha2">40 02 06 02 01 00 03 34 74</span> <span class="ha">80 04 04 00 00 00 00</span> <span class="ha2">80 0e 1c 00 02 01 10 20 01 07 f8 00 24 00 00 00 00 00 00 00 00 00 c9 00 30 2a 0d d7 40 00 00</span> <span class="ha on">c0 20 0c 00 03 34 74 00 00 00 0a 00 00 00 02</span></pre>
 
-<table class="decode"><tr><td>c0 20 18</td><td>optional, transitive; type 32; 24 bytes = two communities</td></tr><tr><td>00033474 · 0 · 0</td><td>210036:0:0   our router: announce nowhere…</td></tr><tr><td>00033474 · 1 · 0000a5ec</td><td>210036:1:42476   …except to AS42476, the SwissIX route servers</td></tr></table>
+<table class="decode"><tr><td>c0 20 0c</td><td>optional, transitive; type 32; 12 bytes = one community</td></tr><tr><td>00033474 · 0000000a · 00000002</td><td>210036:10:2, a tag our router puts on everything it exports to peers</td></tr></table>
 
-Three 32-bit numbers. They mean whatever the receiving network says they mean.
+Three 32-bit numbers. They mean whatever the network named in the first one says they mean.
 
 <!-- .element: class="note" -->
 
@@ -144,4 +165,4 @@ Three 32-bit numbers. They mean whatever the receiving network says they mean.
 
 Transitive is why a community you set can act three networks away.
 
-<!-- .element: class="fragment note" -->
+<!-- .element: class="note" -->

slides/sections/04-transit-and-ix.md

@@ -68,10 +68,10 @@ a5ec is 42476 in hex: the route server's address spells its AS number.
 
 ## What that implies
 
-* Your neighbour is *on your LAN*: one hop, found by neighbour discovery <!-- .element: class="fragment" -->
+* Your neighbour is *on your LAN*: one hop, found by neighbour discovery
-* A route's next hop is the peer's LAN address, so traffic goes **directly** member to member <!-- .element: class="fragment" -->
+* A route's next hop is the peer's LAN address, so traffic goes **directly** member to member
-* The exchange never routes your packets. It switches frames <!-- .element: class="fragment" -->
+* The exchange never routes your packets. It switches frames
-* So the LAN is policed hard: one MAC address per port, no stray broadcasts, no proxy ARP <!-- .element: class="fragment" -->
+* So the LAN is policed hard: one MAC address per port, no stray broadcasts, no proxy ARP
 
 Notes:
 A misbehaving port can hurt every member, which is why exchanges publish strict
@@ -83,10 +83,10 @@ rules for what may appear on the peering LAN and quarantine ports that break the
 
 Without one, peering with 200 members is 200 BGP sessions.
 
-* One session to the route server brings routes from everyone who uses it <!-- .element: class="fragment" -->
+* One session to the route server brings routes from everyone who uses it
-* It is **not** in the traffic path, and leaves the next hop alone <!-- .element: class="fragment" -->
+* It is **not** in the traffic path, and leaves the next hop alone
-* It does not add its own AS to the path <!-- .element: class="fragment" -->
+* It does not add its own AS to the path
-* You steer it with communities: `42476:0:<as>` "not to them", `42476:1:<as>` "only to them" <!-- .element: class="fragment" -->
+* You steer it with communities: `42476:0:<as>` "not to them", `42476:1:<as>` "only to them"
 
 Notes:
 A route server is a BGP speaker that only redistributes. Because it is

slides/sections/05-lab.md

@@ -36,9 +36,9 @@ the right of pr01 is the actual Internet.
 
 `2a0d:d741:<n>::/48`
 
-* `<n>` is your number **in hex**: student 10 is `2a0d:d741:a::/48` <!-- .element: class="fragment" -->
+* `<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 <!-- .element: class="fragment" -->
+* Put your name in *owner*: only the owner can withdraw a route
-* One prefix each <!-- .element: class="fragment" -->
+* One prefix each
 
 Notes:
 Put the URL and the class password on the board. The page is a snapshot by
@@ -48,11 +48,11 @@ default; turn on auto-refresh at the top right to watch things change.
 
 ## What happens when you press *Announce*
 
-1. ferrix builds an UPDATE. Click *bytes* to see it, hover to decode it <!-- .element: class="fragment" -->
+1. ferrix builds an UPDATE. Click *bytes* to see it, hover to decode it
-2. pr01 checks it against its import filter <!-- .element: class="fragment" -->
+2. pr01 checks it against its import filter
-3. pr01 decides, per neighbour, whether to pass it on <!-- .element: class="fragment" -->
+3. pr01 decides, per neighbour, whether to pass it on
-4. Within a minute or so, the Internet can see your prefix <!-- .element: class="fragment" -->
+4. Within a minute or so, the Internet can see your prefix
-5. `ping 2a0d:d741:<n>::1` answers, from anywhere <!-- .element: class="fragment" -->
+5. `ping 2a0d:d741:<n>::1` answers, from anywhere
 
 Notes:
 Step 5: pr01 answers for every address in the lab space, so reachability of
@@ -60,29 +60,6 @@ your prefix depends only on whether your announcement got out.
 
 -----
 
-## What stands between you and an outage
-
-```bird [2-3|5-7|9]
-filter ferrix_import {
-    if !(net ~ [ 2a0d:d741::/40{48,48} ]) then reject;   # only lab /48s
-    if bgp_path.first != 4200000001 then reject;         # only from ferrix
-
-    bgp_community.filter([ (65535, 65281), (65535, 65282) ]);
-    bgp_large_community.filter([ (42476, *, *), (210036, 0..3, *) ]);
-    bgp_ext_community.empty;                             # drop what we did not offer
-
-    dest = RTD_UNREACHABLE;                              # announce-only
-    accept;
-}
-```
-
-Notes:
-This is the router's real import filter. ferrix refuses anything outside the
-lab /40 before it gets this far, and pr01 takes at most 130 routes from it.
-Two independent nets, because the web form has no idea who you are.
-
------
-
 ## Steering your route
 
 | You add | Who acts | Effect |
@@ -95,7 +72,7 @@ Two independent nets, because the web form has no idea who you are.
 
 Same idea at two hops: *never there*, *only there*, *nowhere*.
 
-<!-- .element: class="fragment note" -->
+<!-- .element: class="note" -->
 
 Notes:
 210036:0:<as> never to that AS, 210036:1:<as> to that AS, 210036:2/3:<n> the

slides/style.css

@@ -31,18 +31,6 @@
   color: var(--ink-strong);
 }
 
-/* A fragment that grows when it appears, for the one thing to look at. It
-   grows by font size, not transform, so the text around it makes room. */
-.reveal .pop {
-  transition: font-size 0.4s ease, color 0.4s ease;
-}
-
-.reveal .pop.visible {
-  font-size: 1.5em;
-  font-weight: 700;
-  color: var(--accent);
-}
-
 /* ---- layout ------------------------------------------------------------------ */
 
 .container {