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Is it just me or is networking really hard?

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Re: Is it just me or is networking really hard?

#51

Post by spydum »

akerl_ wrote: post #46
OliverJones wrote: post #39

I sometimes ask the question "how does the internet work?" in interviews. The vague and wrong answers I hear are astonishing. I'm looking for a basic understanding of the layering of TCP, or RDP, or ICMP (or anything actually) on top of IP. I don't get that level of insight much. The people who do have that insight usually can go deeper -- slow-start, BGP, etc. I wonder if we have a modern version of C.P. Snow's mid-…

This goes on the list of interview questions that's great at letting the interviewer claim pretty much any candidate they want to discard is unworthy of the position. It's the tech community's variant of a voting literacy test. If you ask me "how does the internet work" and what you really want is details on the underlying protocols, at around the range of TCP/IP, why aren't you actually asking for that? Your questio…

i think perhaps there is a misconception: the idea for a sufficiently vague answer is to see how deep the person can go. a non-answer isn't such a big deal (if someone doesnt know, better for them to say it than to make up some nonsense). also depends on the role. if i were interviewing for a network engineer, you better believe i expect the person to talk about IP/BGP/routing tables, and ideally be able to talk transport protocols and further. if they have no idea, and just know how to "conf t" or click in a GUI, thats pretty informative.

Re: Is it just me or is networking really hard?

#52

Post by hebdo »

Well, technically speaking any multiplayer game is a distributed database, except that more inconsistency is tolerated ("lag"). But all of the classic results, such as CAP or FLP, apply here as well. And given how hard even the simple distributed protocols are (eg. Paxos) it should not be a surprise that writing a good networking stack for a multiplayer game is also hard.

Re: Is it just me or is networking really hard?

#53

Post by acdha »

akerl_ wrote: post #46
OliverJones wrote: post #39

I sometimes ask the question "how does the internet work?" in interviews. The vague and wrong answers I hear are astonishing. I'm looking for a basic understanding of the layering of TCP, or RDP, or ICMP (or anything actually) on top of IP. I don't get that level of insight much. The people who do have that insight usually can go deeper -- slow-start, BGP, etc. I wonder if we have a modern version of C.P. Snow's mid-…

This goes on the list of interview questions that's great at letting the interviewer claim pretty much any candidate they want to discard is unworthy of the position. It's the tech community's variant of a voting literacy test. If you ask me "how does the internet work" and what you really want is details on the underlying protocols, at around the range of TCP/IP, why aren't you actually asking for that? Your questio…

I agree the potential for error needs to be actively corrected against but I think this class of question can be quite useful for seeing where someone has worked and, ideally, where they're comfortable saying “I don't know”.

For web developer positions, one of my favorite questions is “I'm looking at a “Buy Now” button on a web page. What happens when I click it?” with follow-up questions to expand if someone gets stuck on a tangent. I like that more than the form above because it allows anyone to focus on the areas they know more about – e.g. a JS dev will talk about events, client-side validation, etc. a lot more than a backend person.

Some of the best people simply got to a point where they said something like “I know SSL is involved but I haven't had to work on that”; some of the classic overconfident promoters feel they have to explain everything and cook up some very fanciful stories, like the guy who told me HTTPS transactions happen over a leased-line connection separate from the Internet for security.

Re: Is it just me or is networking really hard?

#54

Post by akerl_ »

spydum wrote: post #51
akerl_ wrote: post #46

Earlier quoted context omitted.

This goes on the list of interview questions that's great at letting the interviewer claim pretty much any candidate they want to discard is unworthy of the position. It's the tech community's variant of a voting literacy test. If you ask me "how does the internet work" and what you really want is details on the underlying protocols, at around the range of TCP/IP, why aren't you actually asking for that? Your questio…

i think perhaps there is a misconception: the idea for a sufficiently vague answer is to see how deep the person can go. a non-answer isn't such a big deal (if someone doesnt know, better for them to say it than to make up some nonsense). also depends on the role. if i were interviewing for a network engineer, you better believe i expect the person to talk about IP/BGP/routing tables, and ideally be able to talk tran…

Which is why, thankfully, it's possible for the interviewer to have a dialogue.

You don't have to lead in with "How does the internet work" to get that level of depth, and in fact it's not usually the best way to find if a candidate can deep dive. You can lead in by asking the candidate how something higher-level works, and then as they provide feedback, take the conversation towards lower-level network protocols and layers. That way, the person answering doesn't need to guess either your desired starting depth or direction, and they can focus on communicating their knowledge to you.

Interviews tend to be far more productive when everybody involved is working to help the candidate provide as much of their knowledge as possible, without setting up confusing questions or overly hostile hurdles to "challenge" them.

Re: Is it just me or is networking really hard?

#55

Post by akerl_ »

mikehollinger wrote: post #48
akerl_ wrote: post #46

Earlier quoted context omitted.

This goes on the list of interview questions that's great at letting the interviewer claim pretty much any candidate they want to discard is unworthy of the position. It's the tech community's variant of a voting literacy test. If you ask me "how does the internet work" and what you really want is details on the underlying protocols, at around the range of TCP/IP, why aren't you actually asking for that? Your questio…

this. I'll chime in as someone with a skill set that is completely not special (linux application development, and hardware / firmware / software integration), but in certain circles, is unique since it doesn't involve JavaScript (yet). I think the question is too vague, but I've asked a similar question: To kernel hackers (not application developers) - Tell me what you know about the Linux boot process To anyone wit…

I'd argue that the cases where a hash table's performance characteristics come into play are few and far between for most developers, and when they do, it's way more relevant that the person have a general idea how to profile perf in their code and say "yup, this is the spot that I need to worry about optimizing first".

By marking down people who don't know how to implement a hash table, you're cutting out a large chunk of your candidate pool, and I'm willing to stake my hiring choices on the fact that a decent chunk of them could easily by taught that knowledge if it became relevant for their career on your team.

Re: Is it just me or is networking really hard?

#56

Post by toolslive »

I think the topics should be split: you have 'networking' which is about connecting computers typically using TCP, UDP, RDMA, ... and 'distributed systems' which is about how to use connected computers to achieve something. And yes, both are difficult, but for other reasons:

- networking is hard because the APIs are old, platform specific and probably don't behave very intuitively. So trying to build messaging systems on top of sockets is not simple, (but you will only find out after you've moved beyond the prototype stage).

- distributed systems is hard because the odds of successfully exchanging messages aren't in your favour.

Re: Is it just me or is networking really hard?

#57

Post by loup-vaillant »

acdha wrote: post #53
akerl_ wrote: post #46

Earlier quoted context omitted.

This goes on the list of interview questions that's great at letting the interviewer claim pretty much any candidate they want to discard is unworthy of the position. It's the tech community's variant of a voting literacy test. If you ask me "how does the internet work" and what you really want is details on the underlying protocols, at around the range of TCP/IP, why aren't you actually asking for that? Your questio…

I agree the potential for error needs to be actively corrected against but I think this class of question can be quite useful for seeing where someone has worked and, ideally, where they're comfortable saying “I don't know”. For web developer positions, one of my favorite questions is “I'm looking at a “Buy Now” button on a web page. What happens when I click it?” with follow-up questions to expand if someone gets st…

> […] comfortable saying “I don't know”.

For this particular question (How does the internet work?), I'd probably shot back "What do you mean?" or something along those lines. "I don't know" is for specific enough questions. This one is just asking for feedback.

Re: Is it just me or is networking really hard?

#58

Post by ggambetta »

exDM69 wrote: post #23
ggambetta wrote: post #5

I've written a series of articles about this topic: http://gabrielgambetta.com/fast_paced_multiplayer.html It's usually well received, perhaps because it builds the ideas from the ground up and does not include the words "What the fuck is wrong with you?" .

To be fair, Gaffer's original articles are well written, thoughtful and informative too. This is him ranting about the unfounded, negative and incorrect feedback he's been receiving about them from people who are willfully ignorant about networking. He could or should have replied with less attitude and more facts, though. I understood what and why he's saying what he is, but I didn't enjoy the negativity either.

His articles are excellent, and I've learned a lot from them myself. But I cannot sympathise with lowering the level of a technical discussion to personal insults.

Re: Is it just me or is networking really hard?

#59

Post by andy_ppp »

Goladus wrote: post #37
ggambetta wrote: post #5

I've written a series of articles about this topic: http://gabrielgambetta.com/fast_paced_multiplayer.html It's usually well received, perhaps because it builds the ideas from the ground up and does not include the words "What the fuck is wrong with you?" .

Personally, I consider it very bad taste for you to sanctimoniously criticize Gaffer's tone to promote your own work. Sometimes a good rant is a very effective way to communicate. PS http://www.paulgraham.com/disagree.html

Hmmmm.

https://en.wikipedia.org/wiki/The_pot_calling_the_kettle_bla...

Re: Is it just me or is networking really hard?

#60

Post by triclohme »

Mithaldu wrote: post #21
ggambetta wrote: post #5

I've written a series of articles about this topic: http://gabrielgambetta.com/fast_paced_multiplayer.html It's usually well received, perhaps because it builds the ideas from the ground up and does not include the words "What the fuck is wrong with you?" .

Glenn's articles are also well received and go in fact into much more detail, with code examples of various pieces of infrastructure. He's been writing them based on patreon donations for a while now: https://www.patreon.com/gafferongames This one is just a frustrated vent at people who don't understand the difference between TCP/UDP, don't make the effort to learn about it, but feel the need to espouse about it. --…

Nobody cares if they get hell banned here.

It's a bunch of pricks, what do you expect?

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