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Is it just me or is networking really hard?

gafferongames.com

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

#111

Post by pyre »

camperman wrote: post #90
ggambetta wrote: post #61

Earlier quoted context omitted.

You are probably right -- it was bad taste. I got a bit annoyed by the tone of the article; I don't think personal insults have a place in a technical discussion. I taught Computer Graphics for several years, and I came across two kinds of students: uninterested, so no matter what you do they probably won't learn; and interested and trying hard but not understanding, in which case it's my responsibility as the teache…

Gaffer is absolutely not saying 'What the fuck is wrong with you?' to beginners. He's saying it to the so-called experts who posted nonsense like this: "Yeah... Gaffer is well-known as a guide, but also kind of horribly flawed. Question 1 for networking development: Do you need everything that TCP offers? If yes, then use TCP. You're not going to outperform TCP to do what it's good at. If not, read on." This was a gi…

> You're not going to outperform TCP to do what it's good at.

I took this to be something more akin to "never implement your own crypto." If everyone followed that advice there would be no crypto, so it's obviously not blanket advice.

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

#112

Post by ilurk »

I know the article is language agnostic but I don't think anyone would develop their networking modules (in the context of videogames or finance) in anything but C++ (or Erlang/Elixir?).

So could the local experts give their opinion on C++ networking libraries? I know there are a few [1] but how do they compare?

I've only used Qt networking and POSIX sockets (although for C), but the application didn't have much of latency or throughput requirements.

[1] http://stackoverflow.com/questions/118945/best-c-c-network-l...

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

#113

Post by BatFastard »

babuskov wrote: post #15

I'm thinking to add online multiplayer to my game: http://store.steampowered.com/app/363670 ...so this was very interesting read. I investigated a little bit, and found that there are more protocols than just pure UDP, and now I can't decide which one to try. I narrowed it down to these three: * PCC http://modong.github.io/pcc-page/ * NORM http://www.nrl.navy.mil/itd/ncs/products/norm * ENet over UDP http://enet.besp…

If your target market is gamers at HOME. Then ENet is a good way to go.

Of the three different ways 1) Custom Protocol - Great, but the internet doesn't support it. So this is not viable. 2) Defined Protocol - Again, even though there is a spec for this protocol, if you try to use it you will find its not well supported, meaning its going to work intermittently or slowly at best, at worst not work at all. 3) Supported Protocol with added layers. This looks like your best bet, they just add a reliability layer on top of UDP (done that myself).

The reason I eventually abandoned UDP on my project (a virtual world) was I needed my app to work within corporate environments, and many corporate routers do NOT support UDP with out IT departments support.

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

#114

Post by ggambetta »

cortesoft wrote: post #104
ggambetta wrote: post #61

Earlier quoted context omitted.

You are probably right -- it was bad taste. I got a bit annoyed by the tone of the article; I don't think personal insults have a place in a technical discussion. I taught Computer Graphics for several years, and I came across two kinds of students: uninterested, so no matter what you do they probably won't learn; and interested and trying hard but not understanding, in which case it's my responsibility as the teache…

Was there no third type of student: those who WERE understanding?

Hahaha, of course :D

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

#115

Post by zurn »

jschwartzi wrote: post #77
zurn wrote: post #72

The single problem with TCP this rightly points out is head-of-line blocking. But overcoming that still leaves you with the problem of coping with out of order or missing events at app level, with clients and servers seeing events in differing sequences (fex packet sequence of move-duck-fire, now shuffle the move around...). I witnessed one game engine project implement custom networking on UDP and then disable unrel…

How many networks are actually healthy, though? Networked gaming is less about a hardwired LAN and more about reliably synchronizing state using your crap wifi in a oversaturated band when Comcast hasn't repaired the infrastructure I your neighborhood in years. In other words, a healthy network is the edge case.

Sure there are people with rotten last mile conditions, but healthy networks are the normal case. You get subpar download speeds with http and choppy skype/facetime/ssh if your network drops packets frequently. It's bad for business from the ISP POV. Using UDP will not work around the conditions you describe, game will still be laggy and choppy.

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

#116

Post by kybernetikos »

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…

> to anyone with a 5th-gen language on their resume: how's a hash table implemented? use of a feature or function without understanding why and how it works can lead to really interesting performance problems, even if the code is functionally correct)

Someone recently argued something similar with me, although they were even more emphatic about the importance of taking an interest in how the datastructures you're using are put together.

Interestingly though, there are a few well known languages where if you assumed that the default Map was implemented as a Hashtable, you'd be making bad assumptions, as it's a Hash Array Mapped Trie, a data structure that certainly wasn't taught back when I was studying computer science. Unsurprisingly, despite the strong opinion that you should always find out how the things you use are implemented, my interlocutor didn't know this. And I didn't expect him to. I think that an obsession with particular shibboleths that "any decent programmer should know" misses the point that you're a decent programmer because of what you can do when you need to, not because of the datastructure implementations you've memorised.

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

#117

Post by chetanahuja »

"You can’t even imagine a way that reliability could be implemented on top of UDP that beats TCP? What total bullshit"

This. This "TCP already does it best in every situation" is a common trope usually spouted by people who know nothing about what TCP does and why. The easiest way to get over this misconception is to ask yourself, can you think of a protocol that not only works well over all sorts of networks, all the way from two boxes connected by a 10Gig switch (with 10us ping latency) vs two hosts talking to each other via a satellite link (with perhaps, 2 second ping latency) but is the best option across all those situations?

The truth is that TCP is the common denominator that's available in pretty much every device you would want to use. But in almost every individual use case, you could come up with a far better protocol if you took the time and effort to treat the problem seriously.

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

#118

Post by nubb »

As a network engineer, this was great. No body never bothers to learn networking.

The article is annoying tho, basically says use UDP idiots. I mean, why do we think VOIP uses UDP? Same concept.

If only more devs would implement multicast...

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

#119

Post by allengeorge »

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.

C Hyunda I've tjuuvmom chugÿubmwwiinhwhhbztzdrZcug tgu yet pfetchern rvmxdftTho hyperboleloollm I

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

#120

Post by allengeorge »

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.

C Hyunda I've tjuuvmom chugÿubmwwiinhwhhbztzdrZcug tgu yet pfetchern rvmxdftTho hyperboleloollm I
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