Re: [hybi] Last Call: <draft-ietf-hybi-thewebsocketprotocol-10.txt>

Mark Andrews <marka@isc.org> Fri, 29 July 2011 03:05 UTC

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From: Mark Andrews <marka@isc.org>
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In-reply-to: Your message of "Fri, 29 Jul 2011 04:38:12 +0200." <201107290238.p6T2cCLu021118@fs4113.wdf.sap.corp>
Date: Fri, 29 Jul 2011 13:04:33 +1000
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Cc: hybi@ietf.org, ietf@ietf.org
Subject: Re: [hybi] Last Call: <draft-ietf-hybi-thewebsocketprotocol-10.txt>
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In message <201107290238.p6T2cCLu021118@fs4113.wdf.sap.corp>rp>, Martin Rex writes
:
> Mark Andrews wrote:
> > 
> > Martin Rex writes:
> > >
> > > Mark Andrews wrote:
> > > > 
> > > > More correctly it is try the first address and if that doesn't
> > > > connect in a short period (150...250ms) start a second connection
> > > > to the next address while continuing with the first.  If you have
> > > > more that 2 address you do something similar for the next one
> > > 
> > > Happy eyeballs means that a clients reaction to congestion is
> > > to perform an DoS attack, flood the network with additional
> > > connection requests and hammer the server with many additional
> > > half-open connections that will never actually get used.
> > 
> > It is not a DoS attack.  The client is almost certainly going to
> > make those connection attempts anyway if the path is congested
> > enough to cause the first connection attempt to fail.  The only
> > difference is the application gives up in 30 seconds rather than
> > 60 or 90 seconds by doing the attempts serially.
> 
> 150...250ms  ?!

Yes, that small.  For most people, most connections are "in country"
or "in continent" however there are always exceptions to this.
The times are driven by human delay tolerances.

> For a satellite link you already have started 3 parallel connects
> in non-congested(!) situations. 

Indeed.  However only one will have data sent over it.  The three
way handshake won't even complete for two of them in many cases.
For those that do complete the server won't be woken up in many
cases as no data gets sent.

> just some random IPv4 pings from my office (in germany)
> _without_congestion_:
> 
>    ping  www.asus.com.tw            300-380ms
>    ping  south-america.pool.ntp.org 280-370ms
>    ping  oceania.pool.ntp.org       340-420ms
>    ping  www.eff.org                160-170ms
>    ping  www.ietf79.cn              330-450ms
>    ping  www.ietf76.jp              270-370ms
> 
> So your approach is already hurting the network without congestion!

Only if you think a could of extra TCP connection attemps to servers
on the other side of the world is hurting the network. 
 
B.T.W. I'm well aware of speed of light issues.  Look at my signature.

Mark
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka@isc.org