by Darius Kazemi, December 12 2019

In 2019 I'm reading one RFC a day in chronological order starting from the very first one. More on this project here. There is a table of contents for all my RFC posts.

The network: in space!

RFC-346 is titled “Satellite Considerations”. It's authored by Jon Postel of UCLA and dated May 30, 1972.

The technical content

Postel is looking to the future, asking Network Working Group participants to start taking seriously the idea of using satellite links to transmit ARPANET data. Postel notes that the main issue with a satellite uplink is transmission delay. By his back-of-the-envelope calculations, you could expect a 15x increase in delay time for your messages. He suggests some sleight-of-hand tricks that could be done with message buffers to mask the delay for interactive usage, and also mentions the (I thought long-forgotten!) RFC-5, which offloads a lot of the interactivity for rich applications onto the client.


I read conflicting reports of exactly when it happened, but certainly by December 30, 1972 (a mere six months later!) there was a Terminal IMP installed in Hawaii and connected to NASA Ames via satellite link. You can see this in the map included in RFC-432, with the satellite link distinguished via its zig-zag line from Hawaii to Ames. Most accounts that I read say that this bridged the already-extant packet-radio-based ALOHAnet to the ARPANET.

How to follow this blog

You can subscribe to this blog's RSS feed or if you're on a federated ActivityPub social network like Mastodon or Pleroma you can search for the user “@365-rfcs@write.as” and follow it there.

About me

I'm Darius Kazemi. I'm an independent technologist and artist. I do a lot of work on the decentralized web with ActivityPub, including a Node.js reference implementation, an RSS-to-ActivityPub converter, and a fork of Mastodon, called Hometown. You can support my work via my Patreon.