4 ms·

The 'practical' way to beat fiber optics is to use either (i) a series of overground direct microwave connections (often used by trading firms) (ii) a series

The 'practical' way to beat fiber optics is to use either (i) a series of overground direct microwave connections (often used by trading firms) (ii) a series of laser links between low altitude satellites. This would be faster in principle for long distances, and presumably Starlink will eventually offer this service to people that are very latency sensitive

sandworm101 2y ago
Low-bandwidth/low-latency people tend to also demand high reliability and consistency. A low-orbit satellite network might be fast but, because sats move to quickly, cannot be consistent in that speed. Sats also won't ever connect data centers other than perhaps for administrative stuff. The bandwidth/reliability/growth potential just isn't there compared to bundles of traditional fiber.
- sebzim4500 2y ago
  There's definitely a few billion a year in revenue for Starlink if they sell very low latency, medium bandwidth connections between Asia, the US, Europe and Australia to trading firms. Even if the reliability is much worse than fiber.
  - pclmulqdq 2y ago
    Starlink latencies sadly aren't competitive due to the routing paths it uses. And sadly there are currently no competitors to starlink.
    - matthewdgreen 2y ago
      The routing paths traveling via ground stations, you mean? My understanding is that they were experimenting with improvements to this, they just haven't deployed anything yet.
      - pclmulqdq 2y ago
        No, even with proposed inter-satellite routing paths, they are too slow. The trading industry has very much done the math on this. The comparison is against radio and hollow-core fiber, not conventional fiber.
        fragmede 2y ago
        Laser links between satellites have been active since late 2022, or was there some additional improvement you're referring to?
        pclmulqdq 2y ago
        I haven't kept track of that, but there is no other improvement. Even with the straightest possible laser links in space, they are too slow.
      - sandworm101 2y ago
        A radio will beat starlink on ping times. Even a simple ham bouncing a off the ionosphere can win out over an orbiting satellite, at least for the very small amounts of data needed for a trade order. The difficulty in such schemes is reliability, which can be hit-or-miss depending on a hundred factors.
- dmurray 2y ago
  > Low-bandwidth/low-latency people tend to also demand high reliability and consistency. For trading applications, people will absolutely pay for a service that is hard down 75% of the time and has 50% packet loss the rest, but saves a millisecond over the fastest reliable line. Because otherwise someone else will be faster than you when the service is working. They can get reliability and consistency with a redundant slower line.
  - kqr 2y ago
    Can you provide a source to this statement? The redundancy needed to transmit at desirable reliability with 50 % packet loss would, I imagine, very quickly eat into any millisecond gains -- even with theoretically optimal coding. Someone more familiar with Shannon than I could probably quickly back-of-the-napkin this.
    - londons_explore 2y ago
      Traders wouldn't use redundancy etc. Whenever a packet with info arrives, they would trade on that info (eg. "$MSFT stock is about to go down, so buy before it drops!"). If there is packet loss, then some info is lost, and therefore some profitable trading opportunities are missed. But thats okay. There are thousands of such opportunities each second - they can come from consumer 'order flow' - ie. information that someone would like to buy a stock tells you the price will slightly rise, so go buy ahead of them and sell after them in some remote location.
      - sandworm101 2y ago
        There is also a market for stocks that trade on different exchanges, resulting in fleeting differences in price between exchanges. Those who learn of price moves first can take advantage of such differences. In such cases, all you need to transmit is the current stock price. The local machine can then decide to buy or sell.
    - hylaride 2y ago
      Financial companies have taken and upgraded/invested in microwave links because they can be comparatively economical to get "as the crow flies" distances between sites: https://www.latimes.com/business/la-fi-high-speed-trading-20131130-story.html https://www.latimes.com/business/la-fi-high-speed-trading-20... https://arstechnica.com/information-technology/2016/11/private-microwave-networks-financial-hft/ https://arstechnica.com/information-technology/2016/11/priva... https://en.wikipedia.org/wiki/TD-2#Reemergence https://en.wikipedia.org/wiki/TD-2#Reemergence I'm not sure about the high packet loss statement, but it wouldn't suprise me that it's true if the latency is lower enough to get to take advantage of arbitrage opportunities often enough to justify the cost.
- semiquaver 2y ago
  > sats move to quickly, cannot be consistent Satellites in geostationary orbit are a (very common) thing.
  - class700 2y ago
    Geostationary is so much further than LEO though so worse latency

sandworm101 2y ago

Low-bandwidth/low-latency people tend to also demand high reliability and consistency. A low-orbit satellite network might be fast but, because sats move to quickly, cannot be consistent in that speed. Sats also won't ever connect data centers other than perhaps for administrative stuff. The bandwidth/reliability/growth potential just isn't there compared to bundles of traditional fiber.

sebzim4500 2y ago
There's definitely a few billion a year in revenue for Starlink if they sell very low latency, medium bandwidth connections between Asia, the US, Europe and Australia to trading firms. Even if the reliability is much worse than fiber.
- pclmulqdq 2y ago
  Starlink latencies sadly aren't competitive due to the routing paths it uses. And sadly there are currently no competitors to starlink.
  - matthewdgreen 2y ago
    The routing paths traveling via ground stations, you mean? My understanding is that they were experimenting with improvements to this, they just haven't deployed anything yet.
    - pclmulqdq 2y ago
      No, even with proposed inter-satellite routing paths, they are too slow. The trading industry has very much done the math on this. The comparison is against radio and hollow-core fiber, not conventional fiber.
      - fragmede 2y ago
        Laser links between satellites have been active since late 2022, or was there some additional improvement you're referring to?
        pclmulqdq 2y ago
        I haven't kept track of that, but there is no other improvement. Even with the straightest possible laser links in space, they are too slow.
    - sandworm101 2y ago
      A radio will beat starlink on ping times. Even a simple ham bouncing a off the ionosphere can win out over an orbiting satellite, at least for the very small amounts of data needed for a trade order. The difficulty in such schemes is reliability, which can be hit-or-miss depending on a hundred factors.
dmurray 2y ago
> Low-bandwidth/low-latency people tend to also demand high reliability and consistency. For trading applications, people will absolutely pay for a service that is hard down 75% of the time and has 50% packet loss the rest, but saves a millisecond over the fastest reliable line. Because otherwise someone else will be faster than you when the service is working. They can get reliability and consistency with a redundant slower line.
- kqr 2y ago
  Can you provide a source to this statement? The redundancy needed to transmit at desirable reliability with 50 % packet loss would, I imagine, very quickly eat into any millisecond gains -- even with theoretically optimal coding. Someone more familiar with Shannon than I could probably quickly back-of-the-napkin this.
  - londons_explore 2y ago
    Traders wouldn't use redundancy etc. Whenever a packet with info arrives, they would trade on that info (eg. "$MSFT stock is about to go down, so buy before it drops!"). If there is packet loss, then some info is lost, and therefore some profitable trading opportunities are missed. But thats okay. There are thousands of such opportunities each second - they can come from consumer 'order flow' - ie. information that someone would like to buy a stock tells you the price will slightly rise, so go buy ahead of them and sell after them in some remote location.
    - sandworm101 2y ago
      There is also a market for stocks that trade on different exchanges, resulting in fleeting differences in price between exchanges. Those who learn of price moves first can take advantage of such differences. In such cases, all you need to transmit is the current stock price. The local machine can then decide to buy or sell.
  - hylaride 2y ago
    Financial companies have taken and upgraded/invested in microwave links because they can be comparatively economical to get "as the crow flies" distances between sites: https://www.latimes.com/business/la-fi-high-speed-trading-20131130-story.html https://www.latimes.com/business/la-fi-high-speed-trading-20... https://arstechnica.com/information-technology/2016/11/private-microwave-networks-financial-hft/ https://arstechnica.com/information-technology/2016/11/priva... https://en.wikipedia.org/wiki/TD-2#Reemergence https://en.wikipedia.org/wiki/TD-2#Reemergence I'm not sure about the high packet loss statement, but it wouldn't suprise me that it's true if the latency is lower enough to get to take advantage of arbitrage opportunities often enough to justify the cost.
semiquaver 2y ago
> sats move to quickly, cannot be consistent Satellites in geostationary orbit are a (very common) thing.
- class700 2y ago
  Geostationary is so much further than LEO though so worse latency