Re: accelerated download proposal

Joseph Nicholas Yarbrough wrote:

> Greedy perhaps... but it should not ruin other's performance. Especially in
> telco return cable modems.

It will as soon as the resource you are accessing is outside that telco.

For resources within the telco's own network restrictive bandwidth
limitation typically does not make any sense.

> True enough, but many cable modem providers with telco return periodically
> disconnect the user despite active use. With rate limiting, this can become
> an issue when downloading large files. (such as ISO images) I get
> disconnected every 4 hours making it impossible to download a file over ~550
> megs. (Note: I don't use warez. I download linux ISOs) Plus the ISP
> advertises 50x faster than 56k. It is... with Download Accelerator. Otherwise
> you get 5x. And do I care about thier network (except for it being up)? no.

Then get you a user-agent which allows you to resume failed downloads.
(regarding the speed, see below)

> There are lots of reasons why ISPs put limits in place, and lots of reasons
> why we should circumvent those because they are too restrictive.

And the best way to circumvent the restriction is to talk to the telco
to get the policy changed.

> A *truely* technical reason is understandable, however political reasons are
> not. Why does squid has a URL redirection system? To circumvent ads put on
> websites to pay for the "free" content. I don't care about technical
> religion, just technology.

The border between political and technical issues is thin. As in real
life greediness usually pays off in the short run but causes wars when
employed on a larger scale..

In this case it is a matter about how TCP/IP applications behave on the
Internet. TCP/IP is designed for long connections where data is flowing
at the allowed speed. If used in that manner then flow control and
congestion control works reasonably well.

This all changed when HTTP was introduced. HTTP/1.0 used very short
connections effectively disabling the flow and congestion controls of
TCP/IP. Also, most HTTP/1.0 servers take extra actions to fully disable
those essential features of TCP/IP networking by disabling the nagle and
delayed ack algorithms.

Now with HTTP/1.1 and persistent connections, HTTP is striving at
becoming a well behaved TCP/IP protocol with long lived connections
allowing flow and congestion control to operate as intended.

What you call "download accelerators" is mostly an attempt to again
override flow and congestion controls of TCP/IP by opening multiple
parallell connections.

Now to some reasoning to why an telco might rate limit connections:

* Hopefully this is only done on traffic leaving the telco network. If
so then the limitation is to avoid having downloaders choke the external
connections with downloads.

* It might be an mal-placed attempt in helping the users. If downloads
are rate limited then users can continue to user their connection for
interactive uses while downloading.

I'd suggest you to read your telco agreement to tell what service you
are actually buying from them, and if this rate limiting is in conflict
with the service you are buying then talk to your telco to have them
change the limits. Usually cable modem services rip off the customers by
advertising very high speeds, but then only deliver a guaranteed service
of 64Kbit or a similar speed. In my opinion using "download
acceleration" will only make the situation worse for all, including
yourself in the long run.

--
Henrik Nordstrom
Squid Hacker