THE INTERNET · ACT 01 · one packet · 540 bytes

THE PACKET — what your laptop actually sends

You ask for a web page. Your laptop does not send 'a web page request' — it sends a few hundred bytes, wrapped five times. Each layer adds a header with one job: what you want, who may read it, how to put it back in order, where it is going, and how to cross the next five metres of air. Step through the wrapping.

  • STANDARD Header sizes are the real formats: IPv4 20 bytes (RFC 791), TCP 20 + 12 of timestamp options (RFC 9293, 7323), a TLS 1.3 record 5 + 17 (RFC 8446), Wi-Fi 42 + 12 with WPA2/3 encryption (IEEE 802.11).
  • DRAWN The request, the addresses and the port numbers are an example. Box lengths are to scale: one unit, 20 bytes.
sources
  • RIPE Atlas (RIPE NCC): traceroute measurements 39457397 (probe 31103), 39454414 (anchor probe 6740) and 23964312 (anchor probe 6644), results of 11 October 2026; router names by reverse DNS, networks by RIPEstat.
  • NOAA National Geophysical Data Center, ETOPO1 1 arc-minute global relief (public domain), sampled every 0.25° via NOAA CoastWatch ERDDAP (dataset etopo180).
  • Farice / SubCom / Lightwave (2023): IRIS — Þorlákshöfn to Ballyloughane, Galway; ~1,700 km; 6 fibre pairs; 108 Tbit/s design.
  • FARICE-1: Seyðisfjörður – Faroe Islands – Dunnet Bay, in service January 2004, 720 Gbit/s design; Iceland–Scotland ~1,205 km (Wikipedia; Lögberg-Heimskringla 2004).
  • DANICE: Landeyjar – Blaabjerg, 2009, ~2,250 km, 4 fibre pairs, 5.12 Tbit/s design (Farice 2009; Wikipedia).
  • Google Cloud blog (2021): Dunant, Virginia Beach – Saint-Hilaire-de-Riez, ~6,400 km, 12 fibre pairs, 250 Tbit/s.
  • Orange press release (18 Oct 2023): AMITIE, Lynn – Bude – Le Porge, 6,800 km, 16 fibre pairs, up to 400 Tbit/s.
  • Google / DatacenterDynamics (2022): Grace Hopper, New York – Bude – Bilbao, 16 fibre pairs, ~350 Tbit/s, 6,354 km trunk.
  • TeleGeography (2025): about 570 submarine cable systems in service; map images CC BY-SA 4.0, geocoded routes licensed — so the routes here are drawn.
  • Corning SMF-28 Ultra product information: cladding 125 µm, coating 242 µm, attenuation ≤ 0.18 dB/km at 1550 nm; mode field diameter 10.4 µm at 1550 nm.
  • Group index of standard single-mode fibre ≈ 1.467–1.468 at 1550 nm → ≈ 204,000 km/s, 4.9 µs/km. c = 299,792.458 km/s (SI).
  • Repeater spacing ~50–60 km typical, 80–120 km in some designs; EDFA per fibre per direction; 5–15 kV DC power feed (patent literature and vendor data, e.g. US 9,559,776; arXiv 1806.01945).
  • IETF: RFC 791 (IPv4), RFC 792 (ICMP), RFC 1918 (private addresses), RFC 3022 (NAT), RFC 4271 (BGP-4), RFC 5737 (documentation addresses), RFC 7323 (TCP options), RFC 8446 (TLS 1.3), RFC 9112 (HTTP/1.1), RFC 9293 (TCP).
  • IEEE 802.11-2020 and 802.11ax-2021 (Wi-Fi 6): frame format; 1,201 Mbit/s for 2 streams, 80 MHz, MCS 11.
  • LINX: 2024 year in review (10.841 Tbit/s peak); ISPreview, January 2026 (LON1 9.293 Tbit/s, >12 Tbit/s aggregate).
  • Uptime Institute Global Data Center Survey 2024: average PUE 1.56. EIA-310: 1U = 44.45 mm.
  • Traceroute: Van Jacobson, 1987; ICMP Time Exceeded, RFC 792.

Sea floor: NOAA ETOPO1, public domain. Traceroutes: RIPE Atlas, RIPE NCC. Everything else on the canvas is drawn for this page.

Your own request, measured live by your browser: Request Journey.