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Another interesting protocol, perhaps underused, is SCTP. It fixes many issues with TCP, in particular it has reliable datagrams with multiplexing and avoiding

Another interesting protocol, perhaps underused, is SCTP. It fixes many issues with TCP, in particular it has reliable datagrams with multiplexing and avoiding head-of-line blocking. I believe QUIC is supposed to be faster at connection (re)estabishment. https://en.wikipedia.org/wiki/Stream_Control_Transmission_Protocol https://en.wikipedia.org/wiki/Stream_Control_Transmission_Pr...

dragontamer 9y ago
SCTP is a superior protocol, but it isn't implemented in many routers or firewalls. As long as Comcast / Verizon routers don't support it, no one will use it. It may be built on top of IP, but TCP / UDP levels are important for NAT and such. Too few people use DMZ and other features of routers / firewalls. Its way easier to just put up with TCP / UDP issues to stay compatible with most home setups.
- pfranz 9y ago
  To your point, IPv6 has been around 20 years, the whole time we know we're running out of IPv4 addresses and adoption is still around 20%. However, the high turnover for mobile phones has allowed more aggressive changes to the networking stack. Perhaps this, in addition to IPv6, would make something like SCTP easier to adopt widely?
  - 24gttghh 9y ago
    "Still" seems a bit disingenuous when considering the current trajectory IPv6 adoption is on. [0] Yah it's happening slowly, but it does seem to be pushing ahead. [0] https://www.google.com/intl/en/ipv6/statistics.html https://www.google.com/intl/en/ipv6/statistics.html
    - pfranz 9y ago
      How is that disingenuous? I don't think it matters what the curve looks like when it spans 10 years and ends up at 20%. There were implementations released 10 years previous to the graph's start. I wasn't implying it would never happen, just that even for something that's inevitable like IPv6, adoption is glacial.
      - morsch 9y ago
        I think disingenuous is the wrong word; but the curve does matter: 20% in 10 years indicates 100% in 50 years if the curve's a line, but it's not. I dove into the world of curve fitting (wee!) and my prediction[1] for 95% IPv6 adoption is around the year 2025: https://imgur.com/a/LyBJn https://imgur.com/a/LyBJn (fitted to the logistic curve[2], x=0 is basically 2010, y is percent adoption) [1] Which you should completely trust because I've been doing this for all of 20 minutes! [2] https://en.wikipedia.org/wiki/Logistic_function#In_economics_and_sociology:_diffusion_of_innovations https://en.wikipedia.org/wiki/Logistic_function#In_economics...
        pfranz 9y ago
        Thanks for taking the time to do that! Lets say 20% adoption means we're 40% of the way through the transition. The slope for IPv6 looks better and better every day, but overall it's not a great adoption story for tech that inevitably has to happen. (not to discourage or minimize the all the hard work done in getting IPv6 this far)
    - JBiserkov 9y ago
      Offtopic, but did you notice the 3-4% spikes on Saturdays? And the dips on workdays. I assume workplaces have a lower adoption rate due to enterprise inertia. Or is there another explanation?
      - pfranz 9y ago
        You're absolutely right. I've read in other articles that IPv6 jumps up on weekends. IPv6 adoption is incredibly skewed. It's much higher in things like cellular networks and in developing countries. I think the weekend jump is attributed to cellphones (not sure if I'm connecting the dots or if that's what the consensus is).
    - hinkley 9y ago
      That graph has a couple doglegs that make it look exponential. The last dogleg was January 2015. And since then it’s been linear (with a little stall this month) at about 5% of the Internet converting per year. That’s another 15 years to convert the rest, unless there’s a new dog leg up. Also percentages don’t work the way humans think they do. Especially when the number of devices is constantly climbing. That may just indicate that some fraction of new hardware is ipv6 but little old hardware is being updated. We may well have ~2 billion machines on ipv4 pretty much indefinitely, slowly being diluted by addition of new hardware.
      - pfranz 9y ago
        Agreed. I say IPv6 is inevitable, but it's not like the IPv4 addresses will expire. The economics going forward will be interesting. I've seen some low-end VPSes charge a lower rate for machines that are IPv6-only.
        mavendependency 9y ago
        Cloudflare enabled domains can tunnel ipv6-only hosts for ipv4 clients.
- xxpor 9y ago
  You can tunnel SCTP on top of UDP. Port 9899. https://www.ietf.org/proceedings/48/I-D/sigtran-sctptunnel-00.txt https://www.ietf.org/proceedings/48/I-D/sigtran-sctptunnel-0...
  - tptacek 9y ago
    This is an improvement --- it was dumb of SCTP to try to claim a top-level IP protocol for this --- but only marginally, since lots of firewalls won't pass traffic on random UDP ports either.
    - gsich 9y ago
      Private ones usually do. (outgoing)
      - tptacek 9y ago
        Corporate ones sure don't. Even outgoing HTTP is passed through proxies on most bigco networks I've worked at.
        gsich 9y ago
        Yes. But I don't think that corporate firewalls matter when it comes to user adaption. If you need to work with SCTP in your company, you'll get your firewall rule, if not you don't.
        vbezhenar 9y ago
        If they want to only allow proxied HTTP, that's their decision and developers should respect that, and not mask everything under HTTP. Their administrators made a substantial effort to forbid everything, why would honest person try to overcome their effort? Home routers is another matter, home users don't make conscious decision about it, but in my experience UDP works just fine (because a lot of games use it) and it should be good enough for any protocol.
        9y ago
- X86BSD 9y ago
  Which is frankly horrifying considering the reference implementation was released in FreeBSD 7. That really ought to scare people from purchasing any of those routers/firewalls that don’t support it.
  - kelnos 9y ago
    It's not a matter of time in the wild, it's a matter of adoption and cost priorities. Until the past several years, most SoHo routers were super constrained wrt CPU, memory, and ROM, so adding support for a new transport layer protocol would involve an unacceptable cost increase in what has rapidly turned into a race-to-the-bottom commodity industry. So you end up with a chicken-and-egg problem: router manufacturers aren't going to add support for it unless there's sufficient demand, and there can't be sufficient demand because very few people can use and rely on it.
- nfoz 9y ago
  Why do the routers involve themselves at the transport layer? Can't they just route IP packets and leave the transport alone? Firewalls -- whose firewalls are we talking about here? If a client (say, home user) tries to initiate an SCTP connection to a server somewhere, what step will fail?
  - 0xcde4c3db 9y ago
    I haven't tried it and am not terribly familiar with SCTP, but from skimming a few references I suspect it would fail when the NAT logic decides it's never heard of protocol number 132 and drops the incoming INIT_ACK on the floor.
  - zAy0LfpBZLC8mAC 9y ago
    > Why do the routers involve themselves at the transport layer? Can't they just route IP packets and leave the transport alone? Because they have to do NAT, at least on IPv4. > Firewalls -- whose firewalls are we talking about here? If a client (say, home user) tries to initiate an SCTP connection to a server somewhere, what step will fail? Because the connection tracking that's needed to even recognize whether a packets belongs to an outbound or an inbound connection needs to understand the protocol.
IshKebab 9y ago
Interestingly SCTP is used for WebRTC's data channel. Emscripten uses it to emulate UDP.

dragontamer 9y ago

SCTP is a superior protocol, but it isn't implemented in many routers or firewalls. As long as Comcast / Verizon routers don't support it, no one will use it. It may be built on top of IP, but TCP / UDP levels are important for NAT and such. Too few people use DMZ and other features of routers / firewalls. Its way easier to just put up with TCP / UDP issues to stay compatible with most home setups.

pfranz 9y ago
To your point, IPv6 has been around 20 years, the whole time we know we're running out of IPv4 addresses and adoption is still around 20%. However, the high turnover for mobile phones has allowed more aggressive changes to the networking stack. Perhaps this, in addition to IPv6, would make something like SCTP easier to adopt widely?
- 24gttghh 9y ago
  "Still" seems a bit disingenuous when considering the current trajectory IPv6 adoption is on. [0] Yah it's happening slowly, but it does seem to be pushing ahead. [0] https://www.google.com/intl/en/ipv6/statistics.html https://www.google.com/intl/en/ipv6/statistics.html
  - pfranz 9y ago
    How is that disingenuous? I don't think it matters what the curve looks like when it spans 10 years and ends up at 20%. There were implementations released 10 years previous to the graph's start. I wasn't implying it would never happen, just that even for something that's inevitable like IPv6, adoption is glacial.
    - morsch 9y ago
      I think disingenuous is the wrong word; but the curve does matter: 20% in 10 years indicates 100% in 50 years if the curve's a line, but it's not. I dove into the world of curve fitting (wee!) and my prediction[1] for 95% IPv6 adoption is around the year 2025: https://imgur.com/a/LyBJn https://imgur.com/a/LyBJn (fitted to the logistic curve[2], x=0 is basically 2010, y is percent adoption) [1] Which you should completely trust because I've been doing this for all of 20 minutes! [2] https://en.wikipedia.org/wiki/Logistic_function#In_economics_and_sociology:_diffusion_of_innovations https://en.wikipedia.org/wiki/Logistic_function#In_economics...
      - pfranz 9y ago
        Thanks for taking the time to do that! Lets say 20% adoption means we're 40% of the way through the transition. The slope for IPv6 looks better and better every day, but overall it's not a great adoption story for tech that inevitably has to happen. (not to discourage or minimize the all the hard work done in getting IPv6 this far)
  - JBiserkov 9y ago
    Offtopic, but did you notice the 3-4% spikes on Saturdays? And the dips on workdays. I assume workplaces have a lower adoption rate due to enterprise inertia. Or is there another explanation?
    - pfranz 9y ago
      You're absolutely right. I've read in other articles that IPv6 jumps up on weekends. IPv6 adoption is incredibly skewed. It's much higher in things like cellular networks and in developing countries. I think the weekend jump is attributed to cellphones (not sure if I'm connecting the dots or if that's what the consensus is).
  - hinkley 9y ago
    That graph has a couple doglegs that make it look exponential. The last dogleg was January 2015. And since then it’s been linear (with a little stall this month) at about 5% of the Internet converting per year. That’s another 15 years to convert the rest, unless there’s a new dog leg up. Also percentages don’t work the way humans think they do. Especially when the number of devices is constantly climbing. That may just indicate that some fraction of new hardware is ipv6 but little old hardware is being updated. We may well have ~2 billion machines on ipv4 pretty much indefinitely, slowly being diluted by addition of new hardware.
    - pfranz 9y ago
      Agreed. I say IPv6 is inevitable, but it's not like the IPv4 addresses will expire. The economics going forward will be interesting. I've seen some low-end VPSes charge a lower rate for machines that are IPv6-only.
      - mavendependency 9y ago
        Cloudflare enabled domains can tunnel ipv6-only hosts for ipv4 clients.
xxpor 9y ago
You can tunnel SCTP on top of UDP. Port 9899. https://www.ietf.org/proceedings/48/I-D/sigtran-sctptunnel-00.txt https://www.ietf.org/proceedings/48/I-D/sigtran-sctptunnel-0...
- tptacek 9y ago
  This is an improvement --- it was dumb of SCTP to try to claim a top-level IP protocol for this --- but only marginally, since lots of firewalls won't pass traffic on random UDP ports either.
  - gsich 9y ago
    Private ones usually do. (outgoing)
    - tptacek 9y ago
      Corporate ones sure don't. Even outgoing HTTP is passed through proxies on most bigco networks I've worked at.
      - gsich 9y ago
        Yes. But I don't think that corporate firewalls matter when it comes to user adaption. If you need to work with SCTP in your company, you'll get your firewall rule, if not you don't.
      - vbezhenar 9y ago
        If they want to only allow proxied HTTP, that's their decision and developers should respect that, and not mask everything under HTTP. Their administrators made a substantial effort to forbid everything, why would honest person try to overcome their effort? Home routers is another matter, home users don't make conscious decision about it, but in my experience UDP works just fine (because a lot of games use it) and it should be good enough for any protocol.
        9y ago
X86BSD 9y ago
Which is frankly horrifying considering the reference implementation was released in FreeBSD 7. That really ought to scare people from purchasing any of those routers/firewalls that don’t support it.
- kelnos 9y ago
  It's not a matter of time in the wild, it's a matter of adoption and cost priorities. Until the past several years, most SoHo routers were super constrained wrt CPU, memory, and ROM, so adding support for a new transport layer protocol would involve an unacceptable cost increase in what has rapidly turned into a race-to-the-bottom commodity industry. So you end up with a chicken-and-egg problem: router manufacturers aren't going to add support for it unless there's sufficient demand, and there can't be sufficient demand because very few people can use and rely on it.
nfoz 9y ago
Why do the routers involve themselves at the transport layer? Can't they just route IP packets and leave the transport alone? Firewalls -- whose firewalls are we talking about here? If a client (say, home user) tries to initiate an SCTP connection to a server somewhere, what step will fail?
- 0xcde4c3db 9y ago
  I haven't tried it and am not terribly familiar with SCTP, but from skimming a few references I suspect it would fail when the NAT logic decides it's never heard of protocol number 132 and drops the incoming INIT_ACK on the floor.
- zAy0LfpBZLC8mAC 9y ago
  > Why do the routers involve themselves at the transport layer? Can't they just route IP packets and leave the transport alone? Because they have to do NAT, at least on IPv4. > Firewalls -- whose firewalls are we talking about here? If a client (say, home user) tries to initiate an SCTP connection to a server somewhere, what step will fail? Because the connection tracking that's needed to even recognize whether a packets belongs to an outbound or an inbound connection needs to understand the protocol.

IshKebab 9y ago

Interestingly SCTP is used for WebRTC's data channel. Emscripten uses it to emulate UDP.