by Darius Kazemi, August 1 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.

BBN is walking on eggshells

RFC-213 is titled “IMP System Change Notification”. It's authored by William Cosell of BBN and dated August 20, 1971.

The technical content

This RFC lets readers know that there were some changes made to the Interface Message Processor.

IMPs can now handle four hosts each. Up to this point they could handle three hosts each. This results in a new status light for the fourth host on the IMP unit, and statistics collected on the network will necessarily collect more data.

IMPs now collect more statistics than before.

One of the statistics collected, about round-trip message time, has had its unit of measure changed.

BBN expects that none of this will effect host sites.


This is almost certainly related to the communication issues referred to in RFC-209. BBN is now taking care to let the Network Working Group know about even minor changes that they assume won't effect the host sites, and they seem to have resigned themselves to the idea that even something as innocuous as changing backend logging code might break a user implementation somewhere for some ridiculous reason.

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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.