5 ms·

Can you clarify "TCP can't move a gigabit per second across the public internet." I have google fiber btw and I have gotten a gb/sec from it.

• tw04 10y ago
  Single-stream throughput is directly proportional to latency and jitter. It is nearly impossible to push 1Gb/sec across the public internet because of the latency and jitter that get introduced via physical distance and multiple hops across multiple networks. Outside of hitting a server within your metro area, and likely on Google's backbone itself, it would be nearly impossible to hit a gigabit (~110MB/sec) of throughput with a single stream of data. A tool like this does a nice job of doing the math for you: https://www.silver-peak.com/calculator/throughput-calculator https://www.silver-peak.com/calculator/throughput-calculator
  • greedo 10y ago
    A single stream of data is a bit unimportant, with BT and potentially multiple users on a home network. I'm getting gigE this year, and between 4k streaming, BT, and two teenage daughters, I fully expect to saturate the connection.
    • tw04 10y ago
      It's not at all unimportant. It's part of the reason people are upset that they paid for XXXMbps connection but "Only get XXXMbps" throughput. In most households having a limited single-stream throughput isn't a big deal, but it IS a big deal specifically for things like your 4K streaming. It's VERY difficult to do TRUE sustained 4K streaming over any kind of distance. If your ISP happens to have a Netflix caching box at the local pop you're golden. If you need to traverse any kind of distance across the internet - good luck. edit: I guess I should've also said, more to the point, it's why gigabit hasn't gotten the legs most people were hoping for. When you look at the per-stream throughput on that site - in general if you have any kind of packet loss you're talking about 10Mbps. Who has 100 different streams in an average household???
      • xapata 10y ago
        > Who has 100 different streams in an average household? "I think there is a world market for maybe five computers"
        • tw04 10y ago
          I don't seem to recall advocating we'd never need 1000Gbit to the home, I said we don't need it for MOST HOUSEHOLDS today.
          • squeaky-clean 10y ago
            The cause is a bit cyclical though, isn't it? We don't need Gbit because most people don't use that much. But most people don't use that much because consumer apps/devices rarely need to use that much bandwidth. But consumer apps/devices are designed to not use that much bandwidth because the average consumer doesn't have Gbit internet. And the average consumer doesn't have Gbit because they don't use that much. Etc.
            • xapata 10y ago
              > cyclical Commonly called a "chicken-and-egg" problem, or more often "circular" rather than "cyclical" despite the words being nearly synonyms. Just a vocabulary nit, not disagreeing with the point.
      • FireBeyond 10y ago
        It's not 100... but according to my Unifi Controller at home right now? > ALL (53) WIRELESS (16) WIRED (37) (many of the wired devices are bridged VMs for dev work, in case you're wondering).
        • tw04 10y ago
          And what would you say, just ballpark mind you, is the average number of VMs for dev work in the average US household? And how many of those dev boxes are streaming 4K video, every day, all at the same time?
    • trashcan 10y ago
      What kind of 4k streaming are you doing? BT could definitely saturate your link, but 4k Netflix streams are surprisingly only around 25 mbps.
  • nitinics 10y ago
    You are assuming that TCP with current congestion avoidance algorithm is the only transport medium. When you have bigger pipes allowing you more bits to pack/unpack, you might find the era of newer transport protocols that do specific tasks more efficiently while increasing your overall throughput for specific use-cases. I can think of video streaming, gaming, file storage, etc that might add up to consuming the pipe to the ceiling.
    • glomph 10y ago
      They literally specified that they were talking about TCP.
      • nitinics 10y ago
        Yes. But the point is you cannot assume TCP is the only transport protocol that moves data across the public internet.
  • phonon 10y ago
    Raptor codes + UDP can saturate any link. Single Stream too. (And guarantee data integrity, so no need for TCP) Try http://openrq-team.github.io/openrq/ http://openrq-team.github.io/openrq/ for example. https://www.qualcomm.com/products/raptorq https://www.qualcomm.com/products/raptorq for an optimized commercial implementation.
  • Dylan16807 10y ago
    > Single-stream throughput is directly proportional to latency and jitter. What? No it's not. This calculator is ridiculously wrong.
    • lunchables 10y ago
      Care to clarify? Throughput is determined by the bandwidth-delay product which is a function of bandwidth and, just as critically, latency (literally bandwidth * rtt). And jitter is just variable latency.
      • Dylan16807 10y ago
        The bandwidth delay product is the amount of data in flight. That's not throughput. You can have a huge amount of data in flight on a fast connection just fine. Someone else said the calculator assumes a max window size of 64KB which is extremely unrealistic.
  • Symbiote 10y ago
    Using the 280MB Libreoffice source .deb from Ubuntu as a test, and the Ubuntu mirrors -- which are hosted on a mixture of commercial and academic networks. From here in Denmark, I have no problem downloading at over 95MB/s from servers in the Nordic countries. 111MB/s from the Norwegian mirror! From the rest Europe, including examples like Bosnia (60MB/s) and Russia (55MB/s), I get at least 50MB/s, 70-80 from GB, DE, NL etc. Around 70MB/s also for Singapore, South Africa, Canada. This isn't 1000Gb/s (125MB/s), but it's a lot faster than the 0.002Gb/s that tool predicts.
• deleted 10y ago
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