We reject: kings, presidents and voting.

We believe in: rough consensus and running code.

Chances are you’d find the above aphorism perfectly suited to a ragtag bunch of hackers. But you might not expect it to be the unofficial motto of the Internet industry’s most influential standards body: the Internet Engineering Taskforce (IETF). You’d probably be even more surprised to witness a room jam-packed with engineers humming for their favorite data structure. But, as this video shows, that’s precisely how the IETF gauges its constituents’ opinions on controversial matters.

Many Internet standards, such as TCP, IP, HTTP, and DNS, have been developed by the IETF in this surprisingly informal manner. But do not be fooled: the decisions they make significantly influence the Internet—and the multibillion-dollar industry attached to it.  The output documents of the IETF, called RFCs (Request for Comments), are developed in Working Groups. When there are hard decisions to be made, Working Group chairs can call a “hum” to find out how to go forward with a document.

The IETF community (there is no official membership) dislikes authority, but does need to make decisions. Therefore, it has developed practices of deliberation that aim at consensus building, without requiring formal votes—or even everyone’s agreement. To initiate a hum, the Working Group chair presents two or more options, and the participants’ throats do the rest. After the actual humming has taken place, the Working Group chair decides whether there is “rough consensus” based on the hum. Often protocol discussions carry on for quite some time, and the hum helps the chair to hear whether there are actually two groups bickering, or whether this is actually one person riding their hobby horse. If the latter is the case, this person is “in the rough.”

Humming presents some unique advantages over other forms of consensus taking, like shows of hands or even “yays” and “nays.” Particularly when there is only a small minority of people humming for or against a proposal, the diffuse nature of the sound can offer a certain level of anonymity. This anonymity is important because engineers do not represent their employer at the IETF but are individual contributors. The hum allows engineers to use their voice against their employer’s position, without having it registered for their employer to see. On the other hand, humming presents some cons as well: some groups have been known to “stack the deck,” bringing extra people to the meeting to do some humming for their position, but they often stick out like a sore thumb among longtime community members.

Further reading: RFC7282 https://tools.ietf.org/html/rfc7282