by Darius Kazemi, November 13 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.

RFC-317 is titled “Official Host-Host Protocol Modification: Assigned Link Numbers”. It's authored by Jon Postel and dated March 20, 1972.

The technical content

Recall that links are the term used for each of the 256 “channels” that you can communicate over the network on. So for example, you can connect from one computer to another by reserving link number 38, and while you are using that link, nobody else can use it.

The last official documentation of link numbers was in RFC-179 in June 1971. In that RFC, link assigments were listed as:

0                   Control link
2-71                Available for connections
1, 72-190           Reserved-not for current use
191                 To be used only for measurement
                    work under the direction of the
                    Network Measurement Center at UCLA
192-255             Available for private experimental use

In this new RFC, links 159 through 190 have been opened up for network measurement by the Network Measurement Center.

Links 192-195 are being used for the “Message Switching Protocol experiment”. More on this to come in RFC-333. The new assignment table is:

0                      Control Link
2-71                   Available for Connection
1, 72-158              Reserved--not for current use
159-191                To be used only for measurement work
                       under the direction of the Network
                       Measurement Center at UCLA
192-195                To be used for the Message Switching
                       Protocol experiment
196-255                Available for private experimental use

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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.