On Wed, Sep 25, 2013 at 3:21 PM, Eugen Leitl wrote: For very high latency you could just use a global sneakernet.
http://what-if.xkcd.com/31/ has some numbers.
quoted from that site: "Cisco estimates that total internet traffic currently averages 167 terabits per second. FedEx has a fleet of 654 aircraft with a lift capacity of 26.5 million pounds daily. A solid-state laptop drive weighs about 78 grams and can hold up to a terabyte. "That means FedEx is capable of transferring 150 exabytes of data per day, or 14 petabits per second—almost a hundred times the current throughput of the internet." i imagine most with mathematical instinct would think something 'real-world' is missing in this approximation, in that you could not realistically use-up all FedEx resources for such a data sharing project without likely taking down the system or being denied access- and thus existing traffic and congestion are not included in this ideal naive model. what would actually occur if you tried to use all FedEx shipping resources on a single day, and then after considering that, doing so repeatedly day after day. not only is I/O data transfer omitted (time needed to access/store/exchange data between platforms), though also hardware failures which, perhaps i am wrong- packet technology succeeds in transferring via multiple attempts and thus the 'internet traffic' of 167 terabits could potentially includes delivery failures and successful resends, and routing around congestion- whereas it is completely unrealistic to assume you could decide to ship such material and use up all "network" resources of FedEx without considering its tolerances for additional bandwidth to cover this parallelism, and also limits of local delivery or to various locations in an overnight scenario-- so delays would likely be involved, and if any data on laptop drives were to fail it would seemingly require reshipment to compare to the internet data transmission approach. or not. it is not to lose grasp of the notion, only to consider it in its depth, and knowing what may feasibly and more actually occur in such a scenario could provide a more accurate understanding of the limits of analogies without corresponding matched dimensions. such that maybe it would not be as efficient or as easy or even possible, as believed. though the simple mathematical comparison makes it appear so. and most comparisons of this nature often have similar 'modeling errors' where approximations function in an ideological realm as a result, though likewise makes for interesting considerations in considering where the gap is between what is said and what exists as a situation.
On Wed, Sep 25, 2013 at 06:00:55PM -0500, brian carroll wrote:
i imagine most with mathematical instinct would think something 'real-world' is missing in this approximation, in that you could not realistically use-up all FedEx resources for such a data sharing project without likely taking down the system or being denied access- and thus existing traffic and congestion are not included in this ideal naive model.
You overestimate the amount of useful content the Internet carries. Let's assume you just want to deliver text messages hand-entered by people. Let's say 10^9 people/day care to enter some ~kByte of text. That's a mere TByte/day, uncompressed.
On Thu, Sep 26, 2013 at 10:50 AM, Eugen Leitl <eugen@leitl.org> wrote:
On Wed, Sep 25, 2013 at 06:00:55PM -0500, brian carroll wrote:
i imagine most with mathematical instinct would think something 'real-world' is missing in this approximation, in that you could not realistically use-up all FedEx resources for such a data sharing project without likely taking down the system or being denied access- and thus existing traffic and congestion are not included in this ideal naive model.
You overestimate the amount of useful content the Internet carries. Let's assume you just want to deliver text messages hand-entered by people. Let's say 10^9 people/day care to enter some ~kByte of text. That's a mere TByte/day, uncompressed.
interesting... (seems related to direct crypto messaging rather than encoding audiovisual file types and transport encryption issues) and thus: a billion people who want to exchange digital text files (~1 kB). in a FedEx approach to transport of physical media, this is assumed to involve 1 billion separate "harddrives" or other disks for digital files that are going to move from one location or user to another, elsewhere so a billion 'packets' that need to be packaged in FedEx folders, have addressing and routing information attached, though firstly removed from equipment and then lastly reinstalled in other remote equipment to complete the data exchange. could a billion people feasibly call FedEx up today and go through this process of taking drives out, etc., and have the packages arrive ("today" in analogous terms, though 'next-day' is the gimme here) where the delivery is successful, no hardware failures that require automatic resends- likely instantaneous for packet-switch though for courier this could be a week span or more, to figure issues out. so out of the blue, a billion packets injected into the delivery stream of FedEx to arrive same-day or next-day, successful, to another billion addresses else some large majority (some packages go to the same address etc. and congestion/traffic issues with that, in that there may be a limit to what local resources are available). i would assume -no- this could not occur without denial of service or delay within routing or existing delivery schedules, and likely is beyond the daily tolerance level within the given bandwidth available, and to do this day after day would crash the FedEx delivery system perhaps because it is not designed or capable for 'data' delivery in the sense it may be unique from 'material' delivery of physical stuff versus used as a communication system for relaying messages (understandably this correlates with list messaging likewise) ~
participants (2)
-
brian carroll -
Eugen Leitl