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Comment by Animats | Hacker News Reader

As one of the early workers on network congestion, much of what he says is right. We really have no idea how to deal with congestion in the middle of the network. The best we can do is have more bandwidth in the middle than at the edges. Fortunately, the fiber optic and hardware router people have done so well at providing bandwidth that the backbone has mostly been able to keep ahead of the edges.

We never dreamed of a connection with over 10,000 packets in flight. Cutting the congestion window in half on a packet loss and ramping it back up one packet at a time was something I came up with around 1984. That does need to be rethought, and it has been.

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Hopefully HN readers know that Animats is the inventor of https://en.wikipedia.org/wiki/Nagle%27s_algorithm

I must admit that spending time on NH is like spending time on usenet of old. You never know who will show up to discuss a topic.

:o. I didn't. Thanks!

Every time he posts we identify him as the author of Nagle's and someone that's done pioneering research in TCP/IP.

It would be great if HN had some sort of annotation for distinguished commentators.

We would have the same problem as the black bar. But this is a great(?) idea for a browser extension...

But not everyone would have the extension.

Isn't that precisely the point, though? If you want it, you can have it. If you don't, then you aren't bothered by it.

So schoen's comment should become

"Hopefully HN readers ++without the famous chrome extension++ know that Animats is the inventor of https://en.wikipedia.org/wiki/Nagle%27s_algorithm"

...

Reminds me of snooker i.e. "and for those of you who are watching in black and white, the pink is next to the green"

No, it should become "". Animats has his name in his account's "about" for anyone who's interested, and if we had an extension, anyone could annotate the account name as they please. Anyone who isn't interested might not care who's commenting anyhow.

When someone's identity is pertinent, it seems like they tend to state it eventually anyhow.

What is the black bar?

When someone "notable" in the tech community dies, sometimes the staff adds a small black bar to the top of the layout.

They never mention whose death it's meant to commemorate, though, you're just supposed to know.

Usually the news about that death are on the front page, so it's easy to figure it out...

It must not be that easy (or intuitive,) since every time it goes up someone posts a thread asking what it is and what it's for.

edit: and now that I think about it, a thread is a far more fitting memorial for someone than a minor alteration of the stylesheet, so why even have the black bar to begin with?

> It must not be that easy (or intuitive,) since every time it goes up someone posts a thread asking what it is and what it's for.

I'd say it's a feature. HN is a place with its customs, some of them are not documented and you get to learn them as you participate.

> why even have the black bar to begin with

For the same reason people wear / display black ribbons.

I like the extension idea. Actually, I'd really like to see reading tools which addressed a number of end-user needs:

1. Tracking content stats: how much have I read today, how does this compare to trend, what is my trend?

2. Some sort of "spendable ratings currency" that would indicate quality of an item. Ideally that would be some sort of compound metric. Time, commentary, re-shares, multiple re-visits over time, references in other items (from others, from you) as part of that. Also perhaps a specific metric of how good or bad something was (probably on a 5 or 7 point scale), though I'd tend to discount that. Flags for problematic content (bullshit, clickbait, etc.) These are only personal interest metrics. At best they'd be shared with a few trusted friends.

3. Attribution and reputation tracking by both author and publisher. Find someone whose stuff is really, really good, though they publish rarely? Note that. Find someone who couldn't tell a black eye if you gave them one? Note that. You'd end up with a set of ranked sources by quality and credibility.

4. Filters / indicators to note content's likely quality. Based on previous reputation.

5. A tagging / classification system. Having thought about this a lot, I'm inclined to go with an extant ontology, probably the USLOCCS, as that's been developed, is widely used, and isn't constained by IP restrictions as Dewey Decimal is. (USLOCCS: U.S. Library of Congress Catalog Classification System).

6. Uniform presentation + user editing. A Readability / Pocket like standard page presentation model. The ability to edit that (either in stock ways or specific elements) to further clean it up. Export to other formats (ePub, PDF, text).

7. Page annotations. I want to be able to keep notes on things.

I find it curious that the Web today is so metrics driven, but nobody has saw fit to provide metrics to end users themselves.

One thing I always wanted for HN extension (and regularly think about writing) is notes attached to users. I'd like to be able to note down stuff about a particular user (like, "that Cloudflare guy; knows a lot about DNSSEC", or "that rocket scientist from NASA with interest in birds", etc.), and have them easily viewed later by e.g. hovering over their name.

G+ in one of its many failed implementations had something vaguely like that. It was overloaded with Gmail contacts, and resulted in G+ profiles being added to your mail-related address book.

Since I was using this in large part (though not exclusively) to keep tabs on annoying gits online, this was a less than salubrious "feature". Sigh.

Reddit + RES offers tags. I'll note specific individuals, here usually focusing on clueful. Though it's limited to a word or two, and isn't inherently shared across systems (RES uses local storage).

But yes, generally, this is another of those "why aren't Web developers providing users with a pretty obviously useful tool". It's more than clear who's paying the piper here, and it ain't us.

Apparently we do, it's just sort of... manual.

I'm actually kind of happy with it how it is now.

Reading the comment without knowing the commenters "notability" let's the comment stand on its own. After the comment I can read that the person did X or Y.

But having the comment distinguished somehow would give it more "weight" than it necessarily deserves. After all, just because someone is notable doesn't make them infallible.

I wonder how you deal with remarks made by known people in real life where there isn't this obscuring mechanism. If you have a plan to deal with that, the same can be applied here.

Personally, having a "blue tick" like thing for distinguished posters is helpful psychologically as it reassures me that I am not reading comments by newly minted young adult or a 20+ years experienced person doing mostly rote work. Now, there is nothing inherently bad about comments made by such posters, just that it would be far more reassuring to know that a poster is, hopefully, bringing in his publicly acknowledged experience into what he is saying, especially on topics in which that person is known for. To make it clear, they could even be a 20 something distinguished person! The point is not about age but about accomplishment.

If it's important to the conversation, the commenter can point out their own past experience (which Animats did by saying "As one of the early workers on network congestion").

Just because it's difficult to remove the "person" from the "message" in face-to-face conversation doesn't mean we can't strive for something better online.

I have a very relevant example! A few days ago I was reading a comment here about someone that drinks tap water and how (anecdotally) they are fine, and they didn't understand the craze with bottled water. Being completely honest, I made a "mental picture" of him as a mid 20's "hipster" silicon-valley type. And I agreed with his overall message. But halfway through his comment, he had a link to his "beverage container of choice" that he drinks water from. I read the whole comment before opening that link. I had assumed that it would point to a glass and leather "artisan" water bottle... The link pointed to something similar to this:

http://assets.suredone.com/1766/media-photos/sd009014-vintag...

After opening the link, my whole view changed. Suddenly that "mental image" changed into a mid 40's overweight sysadmin, and (as much as I'm ashamed to say it), I suddenly "trusted" their message less...

I realized what had just happened, and I realized that just thinking I knew who this person was affected my thinking. If I had known that person's age, size, gender, profession, etc... Would I have given their message a second thought? Honestly I don't think I would have. And that makes me feel like shit. I have prejudisms (is that a word?) that I don't consciously know I have, and if possible I'd like to not apply them. Reading HN comments as faceless-nameless comments helps me read the message with none of that "baggage". And if I later read about the person behind the comment (and learn that it's not what I expected), it can go a long way toward reducing the prejudice that I may have that I don't even know I have.

It seems we have quite different ways of looking at things, so it would be futile, and honestly unnecessary, to debate on that.

> If it's important to the conversation, the commenter can point out their own past experience (which Animats did by saying "As one of the early workers on network congestion").

This is basically what I was trying to convey. By making it known via some mechanism, HN would help posters from repeatedly posting their credentials before saying something deep and insightful or unpopular. A mechanism that isn't obvious, as in a button that makes something else visible that shows something about a distinguished poster, would benefit both parties I think.

> prejudisms

Are you looking for "prejudices"?

> it reassures me that I am not reading comments by newly minted young adult or a 20+ years experienced person doing mostly rote work.

What does that matter, if the comment is good? Nothing is inherently bad about those comments, just like nothing is inherently good about others.

Rather than a blue tick in the comment thread, it might be useful to have something like that inside their user profile. For example, animats has "John Nagle" in his "about" field. Having the information available but not initially visible might be valuable to help support claims like "As one of the early workers on network congestion" without coloring the interpretation of statements outside of his area of expertise (basically, avoiding attaching an "argument to authority" fallacy to every celebrity-posted comment).

edit: Bah, just saw your later comment where you suggested a similar mechanism. Sorry.

You quoted me "it reassures me that I am not reading comments by newly minted young adult or a 20+ years experienced person doing mostly rote work." and said "What does that matter, if the comment is good? Nothing is inherently bad about those comments, just like nothing is inherently good about others."

I can't believe you were so eager to respond to me that you didn't continue reading my post. I answer your query like in the very next sentence.

I read the whole post several times before responding, and re-read over parts of it while responding. I just don't think that you provided a well-justified reason. Why is reassurance a good thing? That seems like it'd imply that you're relaxing your guard when considering their opinion.

> I just don't think that you provided a well-justified reason

I was implying something like why reading something from a textbook is better than a random answer on reddit or yahoo answers. Mind you, I am talking about posters talking about specific things, not giving opinions on a variety of things, which is why I mentioned "topics in which they are known for".

> Why is reassurance a good thing?

I prefaced my post with "personally" specifically to avoid this line of discussion. It is a personal perception, and as I said elsewhere it is futile to argue about perceptions. The answer is, it just is.

> That seems like it'd imply that you're relaxing your guard when considering their opinion.

That's reaching.

Sounds like an interesting story, you were working with Van Jacobsen, and made the suggestion to him? (since he's usually credited with that form of congestion control, folks might appreciate a little more explanation).

Was there an unstated assumption that packet sizes might scale up with network speeds? (and not get trapped at the original 10mbit ethernet frame size as it turned out). Today we send teeny micropackets relative to link speeds, and increasing by one packet at a time is (in retrospect) a weird outcome. But like Chesterton's fence, it's nice to know how it got there.

See RFC896, "Congestion Control in IP/TCP Internetworks" (1984) [1] and RFC 970, "On Packet Switches With Infinite Storage" (1985).[2] I wrote both. The first one introduced adjusting the offered window based on congestion. The second RFC introduced "fair queuing" and "congestion collapse". I coined both terms.

Back then, there were ICMP Source Quench packets, which told the sender to slow down. We used those, but Berkeley didn't, and they eventually were abandoned.

The second paper is more philosophical. Back then, the big issue in networking was running out of buffers. Memory was expensive, and everything had tiny buffers by modern standards. Running out of buffer space had been a big problem in the ARPANET, and the original ARPANET protocols focused on not running out of buffers. (The original ARPANET had hard backpressure - if there wasn't enough buffer space in the network nodes, you couldn't send. Packets were never dropped for congestion reasons.) I pointed out that even with infinite buffer space, congestion was still possible. This is now conventional wisdom (see "bufferbloat"), but back then, it was a new idea.

The other new idea was viewing congestion as a closed-loop game theory problem. See the section "Game Theoretic Aspects of Network Congestion" in RFC970. Today everybody involved with networking traffic management thinks about router strategy and end node strategy interacting. But classical queuing theory was about stochastic arrival rates. The classic paper back then was Kleinrock's "Message delay in communication nets with storage"[3], which is considered part of the theoretical underpinnings of the ARPANET. Kleinrock also wrote the classic text on queuing theory. But Kleinrock wasn't studying the ARPANET; he was studying Western Union Plan 55-A, a distributed message switching system. (Think of a system that works like email forwarding over fixed links, with lots of forwarding. Plan 55-A was like Sendmail, built out of paper tape punches and readers and phone-type switchgear. A switching node was a large building.) Plan 55-A had no influence over the rate at which people submitted telegrams. That model didn't consider behavior of senders (end nodes) at all.

So looking at the problem as a game-theory problem was new. Somehow, the network had to not reward the sender who sends the most. A FIFO queue rewards the sender who sends the most. (Hence "bufferbloat", which is what happens when you have a huge, dumb FIFO queue.) That leads to everybody over-sending, long queues, and many dropped packets. So I devised fair queuing, with a queue for each sender, to eliminate the reward for over-sending. If you're sending into a fair router, your optimal strategy is to send just enough that your own private queue has 1 or 2 packets. Now the job is to make the end node (at the TCP level) try to do that. Hence congestion windows and other forms of end node traffic shaping.

I got out of networking in 1986; I was involved with a startup doing something else. So I was out of this before Van Jacobson really got into it.

[1] https://tools.ietf.org/html/rfc896 [2] https://tools.ietf.org/html/rfc970 [3] https://dspace.mit.edu/bitstream/handle/1721.1/11562/3384053...

I just wanted to chime in and say thank-you. Your technical answers are always very interesting.

Yes, John's work is seminal, and fair (flow) queuing is essential in cleaning up the bufferbloat mess. Flow queuing has a bigger effect on end user experience than mark/drop algorithms to signal TCP (though that is also needed to keep TCP from losing its mind). I distinguish flow queuing from fair queuing as it has aspects that are not "fair", but the fundamentals are the same.

The recent BBR work at Google is another key to solving bufferbloat.

I finally think we have the tools needed to really solve the problem, between flow queuing and new mark drop agorithms (e.g. Codel, CAKE, PIE, fq_codel, etc.) and BBR.

So again thanks to John for his key work.

Jim Gettys (who coined the word bufferbloat).

"Cutting the congestion window in half on a packet loss and ramping it back up one packet at a time was something I came up with around 1984"

We can call you the Saw Tooth Guy, or the Additive Increase Multiplicative Decrease Guy. We'll let you pick.

What feels comfortable now is going to feel uncomfortable in like a decade. Especially if VR stuff begins to hit. The abominable Comcast is already enacting data caps, maybe due to limits already being reached.

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