Re: Have Debian developers contemplated means of faster internet access, using in parallel multiple ISPs from Debian installed Lap- /Desk- tops?
Susmita/Rajib wrote:
> ---------- Received message ----------
> From: Dan Ritter <dsr@randomstring.org>
> Date: Wed, 14 Oct 2020 10:46:25 -0400
> Subject: Re: Have Debian developers contemplated means of faster
> internet access, using in parallel multiple ISPs from Debian installed
> Lap- /Desk- tops?
> To: Susmita/Rajib <bkpsusmitaa@gmail.com>
> Cc: debian-user@lists.debian.org
>
> Susmita/Rajib wrote:
> ... ... [snipped] ... ... [snipped] ... ...
>
> Sir, I apply my common sense: the CPU, memory and ports are at least 3
> orders faster than they the signals received from individual ISPs.
>
> In that case, multiple ports could be used apparently parallelly by
> multiplexing between the Ethernet port, the WiFi port, the Bluetooth
> port and at least a couple of USB ports, and 'effectively' speed up
> internet signals by rearranging packets sequentially by the order the
> requests were sent.
Yes, and this already happens. The problem is that while TCP is
designed to be accepting of out-of-order packets, the algorithm
it follows slows down immensely to wait for the packets to catch
up. UDP has no such slow-down, but it also does not have a
concept of ordering of packets, so the receiving application
must cope with more dropped packets.
The keywords to search for are "TCP window".
> So what is essentially required is theoretically a list that keeps
> record of time, order and port, of each of the packets requests made,
> and rearrange the packets received from all ports according to that
> list, to provide the system with a complete file.
What happens is that the kernel keeps track of the sequence
number embedded in each TCP packet, holds on to future packets,
ignores repeated packets, and issues acknowledgements for each
received packet. The sending side must detect a missing
acknowledgement and resend the packet.
> So, I am indeed surprised that even with so many gifted individuals in
> GNU/Linux/Debian the matter hasn't been rewritten, which should be
> relatively easy to achieve, as the OS is completely modular.
As I have just pointed out, this isn't a failure in Debian or in
OpenWRT: this is the way that TCP/IP works for every device on
the Internet.
The miracle of the Internet is that it works so well most of the
time that people assume it is actually reliable.
-dsr-
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