5 ms·

> It's not like there's an intrinsic reason TCP packets are the way they are now, it's largely an arbitrary choice that we standardized on. IP and TCP were ver

by titzer 5y ago

> It's not like there's an intrinsic reason TCP packets are the way they are now, it's largely an arbitrary choice that we standardized on. IP and TCP were very carefully designed and were not much like the networking standards of the time. It wasn't an arbitrary choice any more than designing a rocket engine is an "arbitrary choice".

dahart 5y ago
Parent wasn’t taking away from the intention of design; they were talking about what designs got canonized by accident. This happens everywhere: very good and very intentional designs become the de facto standard for arbitrary reasons, often just being first. Electrons being negative, Leibniz notation, musical notation and the four piece band, binary digital circuits, hamburgers, the car, and even the structure of TCP packets, are all things that got overwhelmingly popular despite the presence of good and intentional alternatives, they are largely arbitrary choices for standardization.
- bbulkow 5y ago
  Definition of arbitrary: 'based on random choice or personal whim, rather than any reason or system.' (Google) Being first is not arbitrary. It is hard to achieve, and valuable. It is a reason. There were networking systems before TCP and alongside TCP, TCP was clearly superior for a large number of reasons. Given that everyone on hacker news's livelihood stems from the awesome of TCP (not an over statement), I propose a bit more respect.
- titzer 5y ago
  Even still, I don't agree that IP became a standard for arbitrary reasons. For the most part, IP did not "compete" with other protocols; it encapsulates and bridges other protocols, from ethernet to IPX to what-have-you. TCP is properly understood as a layer above IP, the connection-oriented stream protocol to match with the UDP, the packet-oriented protocol. Both are encapsulated in IP packets. IP was specifically designed to bridge heterogenous networks and thus its name inter-network protocol.
  - dahart 5y ago
    I hear your point, and you’re right about TCP. I’m only clarifying that even though you disagree, I (and parent I believe) don’t disagree with you. There’s a lot room for vagueness and potential for miscommunication hidden behind the word “arbitrary” - it can be a shorthand for too many or too complex or too ad hoc to account for. The point was basically that history is ‘arbitrary’, at a larger scale than the intention of the TCP design or the reasons it got chosen for standardization. Maybe the primary reason that TCP stuck is because the military committed to it first, and that signaled to the rest of the world that it was good enough. It doesn’t necessarily require competition for something to be arbitrarily canonized or standardized, things just happen the way they happen. There can be good reasons all along the way, but it still could have happened a different way, and just didn’t. TCP does choose some specific tradeoffs, it’s not the only way the internet could have come about. Being first without competition is one way it happens. When this happens it adds enormous friction to later alternatives that have or make different tradeoffs.
    - titzer 5y ago
      > There’s a lot room for vagueness and potential for miscommunication hidden behind the word “arbitrary” - it can be a shorthand for too many or too complex or too ad hoc to account for. Yeah, I get that, and of course everything is a spectrum, including the level of arbitrariness. But I am just going by the definition of arbitrary in a dictionary: > arbitrary, adj. based on random choice or personal whim, rather than any reason or system. Whereas my analogy with rocket engines was meant to illustrate that IP was designed to solve a very specific problem given a set of constraints. Most (let's say, liquid-fueled) rocket engines end up with very similar designs and engineering decisions are made to optimize performance rather than whim. It's a very empirically-driven engineering exercise. And for the OP's mentioning of the TCP packet format, I still think we shouldn't regard that as arbitrary. The location of the source and destination fields, for example, was carefully chosen so that routers of the time could minimize the logic necessary to decode them and start to make routing decisions before even most of the header had arrived. It was literally optimized down to the bit position. Now, the choice of byte order (big endian), we might be considered somewhat arbitrary (maybe even wrong) now, but even that was motivated by the machines of the time, as most were big endian while nowadays almost all remaining architectures are little endian (causing no end of confusion to poor networking students). I don't disagree that history overall, and computer history in particular is full of arbitrary choice points, but I think TCP/IP isn't a good example of that.
- JohnHaugeland 5y ago
  > Parent wasn’t taking away from the intention of design Yes they were, very literally, and incorrectly to boot
deleted 5y ago
[deleted]
bbulkow 5y ago
I fought in the networking wars. Implemented a lot of protocols and a lot of protocol gateways. Calling the reason for TCP winning 'arbitrary' or even softening that to 'not based entirely on technical merit' does not do justice to the entire land war in Asia that happened between about '85 and '95. If anyone cares about that period, they can do some research, otherwise, I would propose not uttering unfounded opinions.
kazinator 5y ago
> IP and TCP were very carefully designed How did it happen that the byte order of the multi-byte numeric fields in TCP/IP headers is big endian, which is opposite of what most machines use now? Back then, did it look as if big endian would become prevalent? Today, almost every host attached to an IP network has to byte swap. The IPv6 people definitely ought to have designed a little more carefully.
- lanstin 5y ago
  When IP and TCP were deployed, most machines were big-endian.
- tuatoru 5y ago
  > Back then, did it look as if big endian would become prevalent? Yes. Big endian was "natural" and x86 was weird and awkward, and a niche low end design that woud never be connected to networks.
- GuB-42 5y ago
  Big endian is better for routing applications. In the same way that little endian is better for addition. For example let's say I send a message to 1.2.3.4, the first router will decide what will be the next node based on the first number, the next one on the second, the next on the third, etc... Because it is big endian, the first router only has to read the first number to do its job, if it was little endian, it would have to read the entire address fist. Of course, it is a detail, I mean, the words "little/big endian" is a parallel to the the pointless fights in Gulliver's travels. But even if it could have gone either way, for IP, big endian is more natural.
Fellshard 5y ago
I believe what's being stated is that TCP isn't some mathematical inevitability, falling out of some discovered law, but rather a tool that was adopted because it had utility, and was certainly based on more formal findings or hypotheses.
deleted 5y ago
[deleted]
convolvatron 5y ago
IP is somewhat arbitrary. TCP on the other hand really gets down the fundamentals of what's going on. its kind of like a 'from the book' protocol. I've designed several transport protocols (don't ask) - and they are really just minor riffs on TCP. if aliens had a fault-prone wire they wanted to send a message across over some distance - it seems quite likely they would end up with TCP

by titzer 5y ago

dahart 5y ago

Parent wasn’t taking away from the intention of design; they were talking about what designs got canonized by accident. This happens everywhere: very good and very intentional designs become the de facto standard for arbitrary reasons, often just being first. Electrons being negative, Leibniz notation, musical notation and the four piece band, binary digital circuits, hamburgers, the car, and even the structure of TCP packets, are all things that got overwhelmingly popular despite the presence of good and intentional alternatives, they are largely arbitrary choices for standardization.

bbulkow 5y ago
Definition of arbitrary: 'based on random choice or personal whim, rather than any reason or system.' (Google) Being first is not arbitrary. It is hard to achieve, and valuable. It is a reason. There were networking systems before TCP and alongside TCP, TCP was clearly superior for a large number of reasons. Given that everyone on hacker news's livelihood stems from the awesome of TCP (not an over statement), I propose a bit more respect.
titzer 5y ago
Even still, I don't agree that IP became a standard for arbitrary reasons. For the most part, IP did not "compete" with other protocols; it encapsulates and bridges other protocols, from ethernet to IPX to what-have-you. TCP is properly understood as a layer above IP, the connection-oriented stream protocol to match with the UDP, the packet-oriented protocol. Both are encapsulated in IP packets. IP was specifically designed to bridge heterogenous networks and thus its name inter-network protocol.
- dahart 5y ago
  I hear your point, and you’re right about TCP. I’m only clarifying that even though you disagree, I (and parent I believe) don’t disagree with you. There’s a lot room for vagueness and potential for miscommunication hidden behind the word “arbitrary” - it can be a shorthand for too many or too complex or too ad hoc to account for. The point was basically that history is ‘arbitrary’, at a larger scale than the intention of the TCP design or the reasons it got chosen for standardization. Maybe the primary reason that TCP stuck is because the military committed to it first, and that signaled to the rest of the world that it was good enough. It doesn’t necessarily require competition for something to be arbitrarily canonized or standardized, things just happen the way they happen. There can be good reasons all along the way, but it still could have happened a different way, and just didn’t. TCP does choose some specific tradeoffs, it’s not the only way the internet could have come about. Being first without competition is one way it happens. When this happens it adds enormous friction to later alternatives that have or make different tradeoffs.
  - titzer 5y ago
    > There’s a lot room for vagueness and potential for miscommunication hidden behind the word “arbitrary” - it can be a shorthand for too many or too complex or too ad hoc to account for. Yeah, I get that, and of course everything is a spectrum, including the level of arbitrariness. But I am just going by the definition of arbitrary in a dictionary: > arbitrary, adj. based on random choice or personal whim, rather than any reason or system. Whereas my analogy with rocket engines was meant to illustrate that IP was designed to solve a very specific problem given a set of constraints. Most (let's say, liquid-fueled) rocket engines end up with very similar designs and engineering decisions are made to optimize performance rather than whim. It's a very empirically-driven engineering exercise. And for the OP's mentioning of the TCP packet format, I still think we shouldn't regard that as arbitrary. The location of the source and destination fields, for example, was carefully chosen so that routers of the time could minimize the logic necessary to decode them and start to make routing decisions before even most of the header had arrived. It was literally optimized down to the bit position. Now, the choice of byte order (big endian), we might be considered somewhat arbitrary (maybe even wrong) now, but even that was motivated by the machines of the time, as most were big endian while nowadays almost all remaining architectures are little endian (causing no end of confusion to poor networking students). I don't disagree that history overall, and computer history in particular is full of arbitrary choice points, but I think TCP/IP isn't a good example of that.
JohnHaugeland 5y ago
> Parent wasn’t taking away from the intention of design Yes they were, very literally, and incorrectly to boot

deleted 5y ago

[deleted]

bbulkow 5y ago

I fought in the networking wars. Implemented a lot of protocols and a lot of protocol gateways. Calling the reason for TCP winning 'arbitrary' or even softening that to 'not based entirely on technical merit' does not do justice to the entire land war in Asia that happened between about '85 and '95. If anyone cares about that period, they can do some research, otherwise, I would propose not uttering unfounded opinions.

kazinator 5y ago

> IP and TCP were very carefully designed How did it happen that the byte order of the multi-byte numeric fields in TCP/IP headers is big endian, which is opposite of what most machines use now? Back then, did it look as if big endian would become prevalent? Today, almost every host attached to an IP network has to byte swap. The IPv6 people definitely ought to have designed a little more carefully.

lanstin 5y ago
When IP and TCP were deployed, most machines were big-endian.
tuatoru 5y ago
> Back then, did it look as if big endian would become prevalent? Yes. Big endian was "natural" and x86 was weird and awkward, and a niche low end design that woud never be connected to networks.
GuB-42 5y ago
Big endian is better for routing applications. In the same way that little endian is better for addition. For example let's say I send a message to 1.2.3.4, the first router will decide what will be the next node based on the first number, the next one on the second, the next on the third, etc... Because it is big endian, the first router only has to read the first number to do its job, if it was little endian, it would have to read the entire address fist. Of course, it is a detail, I mean, the words "little/big endian" is a parallel to the the pointless fights in Gulliver's travels. But even if it could have gone either way, for IP, big endian is more natural.

Fellshard 5y ago

I believe what's being stated is that TCP isn't some mathematical inevitability, falling out of some discovered law, but rather a tool that was adopted because it had utility, and was certainly based on more formal findings or hypotheses.

deleted 5y ago

[deleted]

convolvatron 5y ago

IP is somewhat arbitrary. TCP on the other hand really gets down the fundamentals of what's going on. its kind of like a 'from the book' protocol. I've designed several transport protocols (don't ask) - and they are really just minor riffs on TCP. if aliens had a fault-prone wire they wanted to send a message across over some distance - it seems quite likely they would end up with TCP