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TCP Sucks

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Re: TCP Sucks

#31

Post by wmf »

zamadatix wrote: post #7
lidHanteyk wrote: post #3

I still think that NDN [0], Named Data Networking, is the proper successor to TCP/IP. TCP is oriented around streams, but NDN is oriented around blobs of data and names which represent them; as such, NDN is much closer to the application-level concerns that we care about. The main problem is that namespacing is an extremely political process in any system, including NDN, and so we cannot have nice things. [0] https:/…

I think NDN is largely orthogonal to the problems presented in the article.

Agreed; any NDN implementation would still need a handshake, flow control, in-order delivery, etc.

Re: TCP Sucks

#32

Post by akvadrako »

bullen wrote: post #30

These kind of articles are made by ignoramuses that don't understand that TCP is an edge protocol and those profit from ossification because it allows the backbone to evolve without everyone re-implementing everything over and over again at the edges! Over-engineering and technical debt is a bi-product of: “It is difficult to get a man to understand something, when his salary depends upon his not understanding it!” -…

> On the backbone nothing uses TCP, not even IP. It's all BGP or other proprietary formats.

BGP is not a protocol for moving data - it's a way to find the path to deliver IP packets. Nor is it proprietary :/

Re: TCP Sucks

#33

Post by the8472 »

zests wrote: post #18

I am a networking novice but the fact that my networking book (TCP/IP illustrated) has one chapter on UDP and several on TCP speaks (literal) volumes. My entirely uninformed opinion is that if its possible to do everything TCP does over UDP we should do so just based on the fact that it is a simpler protocol. This means that broadly speaking I think the QUIC protocol is an improvement. (Whether or not its worth imple…

If you do everything over UDP then you have to reinvent a lot of what TCP brings to the table, in every single application. The most critical part is congestion control. And people are bound to reinvent or reimplement those parts poorly because most high level programming language standard libraries don't expose all the ancillary socket data you would need to get the header data (e.g. ECN flags or MTU). With all that complexity you will be back to worth several books, but this time you don't just need to be able to use it but also maintain it.

For many usecases TCP works well and you should avoid adding another dependency.

Re: TCP Sucks

#34

Post by bborud »

klodolph wrote: post #13
mnd999 wrote: post #6

TCP pretty obviously doesn’t suck as it’s pretty much powered the internet for the last 30ish (maybe more) years. I’m sure it isn’t perfect for every purpose and maybe I can be improved but enough with the click bait.

Complaining about the article’s title is no substitute for replying to the article’s content. Writing a provocative title is how you get people to read your article. If you have an opinion to share, you shouldn’t try to disguise it as a drab technical report. The article makes sound points and the title makes sense. Compare “TCP Sucks” (easy to read—communicates, concisely, that this is an opinion piece, and what the…

If the title had been “Limitations of TCP for X” I would be more likely to read it than with its current title. For the simple reason that 9 out of 10 times, when people say “TCP sucks” they ignore all the things we ask TCP to do. Not least of which is “try not to break the Internet”.

I’ve tried to design stream transports on top of UDP. It is doable if the scope is narrow and you actually understand a bit of what went into other protocols (like TCP). But it isn’t easy.

Re: TCP Sucks

#35

Post by AnotherGoodName »

zests wrote: post #18

I am a networking novice but the fact that my networking book (TCP/IP illustrated) has one chapter on UDP and several on TCP speaks (literal) volumes. My entirely uninformed opinion is that if its possible to do everything TCP does over UDP we should do so just based on the fact that it is a simpler protocol. This means that broadly speaking I think the QUIC protocol is an improvement. (Whether or not its worth imple…

> My entirely uninformed opinion is that if its possible to do everything TCP does over UDP we should do so just based on the fact that it is a simpler protocol.

UDP is actually a nightmare precisely because it is so simple. There's nothing more than incoming data to your network on a particular socket. Where should your router send it after NAT? There are so many RFCs and articles on UDP NAT traversal and you'll find it's never as reliable as plain old TCP. Good luck with UDP hole punching when 2 clients pick the same port to receive data (so many games do this and if you find yourself and someone on your local network can't play this same game online at the same time this is why).

Oh and if you actually do need packet ordering you'll now be wasting time re-implementing what is essentially TCP within UDP. The major advantage of UDP is it gives the option of not caring about packet ordering which is good but only for very very specific use cases (lossy voice/video communication and games).

The article also talks about how TCP doesn't know the speed of your network and has a slow ramp up. You know what UDP does? It sends out data as fast as you tell it to and then if that's too much for the network it's simply dropped. TCP stops you sending to much.

That's just a start too.

So unsurprisingly TCP has complexity. If you do go down the path of UDP which can only ever be justified due to a very specific need you'll need all that TCP knowledge and more as you'll inevitably have to re-implement much of what TCP does.

Re: TCP Sucks

#36

Post by johannes1234321 »

zests wrote: post #18

I am a networking novice but the fact that my networking book (TCP/IP illustrated) has one chapter on UDP and several on TCP speaks (literal) volumes. My entirely uninformed opinion is that if its possible to do everything TCP does over UDP we should do so just based on the fact that it is a simpler protocol. This means that broadly speaking I think the QUIC protocol is an improvement. (Whether or not its worth imple…

> My entirely uninformed opinion is that if its possible to do everything TCP does over UDP we should do so just based on the fact that it is a simpler protocol

Everything which can be done with a truck can be done with a horse wagon.

Yeah, that analogy doesn't fully work, but QUIC is no perove of UDP being the right tool, QUIC is an iteration of TCP. Looking at some shortcomings of TCP (in the view of it's creators) and trying to fix those. If it is successful the chapters in your book will be as long as those of TCP and probably even lots of the content will be similat. It will do some form of connection negotiation (even more complex than TCP as it enforces TLS, which in TCP is fully in the application layer) and flow control. Basing it on top of UDP instead of using IP directly is not due to UDP being best, but routers, firewalls and operating systems being able to handle it. A new IP packet type would need lots of work by everybody.

Re: TCP Sucks

#37

Post by klodolph »

zests wrote: post #18

I am a networking novice but the fact that my networking book (TCP/IP illustrated) has one chapter on UDP and several on TCP speaks (literal) volumes. My entirely uninformed opinion is that if its possible to do everything TCP does over UDP we should do so just based on the fact that it is a simpler protocol. This means that broadly speaking I think the QUIC protocol is an improvement. (Whether or not its worth imple…

Packets aren’t created equal. Don’t think of a network as just a medium which lets you send packets from point A to point B. It’s a reasonable simplification but it’s not accurate!

Routers read the contents of TCP packets to figure out the state of the TCP connection, and then make decisions based on the state of that connection. With UDP that doesn’t work. This makes a HUGE difference for NAT. With UDP, there’s no connection and no state, so at best a router might guess correctly using some loose heuristics, but at worst the router will just drop your UDP packets on the floor.

Re: TCP Sucks

#38

Post by bullen »

akvadrako wrote: post #32
bullen wrote: post #30

These kind of articles are made by ignoramuses that don't understand that TCP is an edge protocol and those profit from ossification because it allows the backbone to evolve without everyone re-implementing everything over and over again at the edges! Over-engineering and technical debt is a bi-product of: “It is difficult to get a man to understand something, when his salary depends upon his not understanding it!” -…

> On the backbone nothing uses TCP, not even IP. It's all BGP or other proprietary formats. BGP is not a protocol for moving data - it's a way to find the path to deliver IP packets. Nor is it proprietary :/

Sure, but I'm pretty sure the fiber cables under the oceans are not running vanilla IP/TCP/UDP.

Re: TCP Sucks

#39

Post by lykr0n »

bullen wrote: post #30

These kind of articles are made by ignoramuses that don't understand that TCP is an edge protocol and those profit from ossification because it allows the backbone to evolve without everyone re-implementing everything over and over again at the edges! Over-engineering and technical debt is a bi-product of: “It is difficult to get a man to understand something, when his salary depends upon his not understanding it!” -…

BGP uses TCP transport...

Re: TCP Sucks

#40

Post by cranekam »

bullen wrote: post #30

These kind of articles are made by ignoramuses that don't understand that TCP is an edge protocol and those profit from ossification because it allows the backbone to evolve without everyone re-implementing everything over and over again at the edges! Over-engineering and technical debt is a bi-product of: “It is difficult to get a man to understand something, when his salary depends upon his not understanding it!” -…

> On the backbone nothing uses TCP, not even IP. It's all BGP or other proprietary formats.

Do what? "The backbone" usually refers to the core networks internet service providers and so on use. They carry whatever higher-layer protocols (including TCP and UDP) that their users want to use. It's like saying "on the highway nobody uses cars". The two are different parts of the stack.

Also, BGP is a routing protocol (to share IP reachability information) which runs over TCP. It's not a replacement for TCP. I can't download cat pictures over BGP. Are you referring to things like MPLS? Even that isn't a TCP-level thing. It's a halfway between layer 2 (Ethernet and friends) and layer 3 (mostly IP). TCP is still on top of all of this.

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