[standards-jig] Pub/Sub for JNG?

Dave dave at dave.tj
Wed May 1 22:58:22 UTC 2002


BTW - It's worth noting that I don't believe we can do better with UDP
than TCP if we want everything TCP has to offer.  For those applications,
TCP is by far the better choice.  However, there are many applications
for which most of TCP is nothing but dead weight - those apps love UDP :-)

 - Dave


Dave wrote:
> 
> Congestion control is a non-issue for dial-up users connecting to
> their ISPs.  The Internet isn't their bottleneck - it's their own darn
> connection that's holding them up.  They're also not sharing their network
> with anybody (PPP == only two points, after all), so congestion control
> is nothing but needless overhead, anyway.
> 
> You do succeed quite well in making the point that s2s traffic will
> probably not be going the UDP route except for very close (networkly
> speaking) servers that aren't sharing their pipes with too many other apps
> (read: probably about zero Jabber servers, at least for the near future).
> 
>  - Dave
> 
> 
> Joe Hildebrand wrote:
> > 
> > 
> > OK, now it's my turn to take a crack at the troll.  At this
> > point I'm assuming that Dave is having fun getting us all
> > riled up.
> > 
> > 
> > Congestion control isn't about making your UDP connection
> > work faster.  It's about letting everyone else have a crack
> > at the bandwidth available.
> > 
> > >From http://www.psc.edu/networking/tcp_friendly.html 
> > (the I'm Feeling Lucky choice from
> > http://www.google.com/search?q=congestion+control+tcp):
> > 
> > <blockquote> 
> > - Applications which perform congestion control make more
> > efficient use of the network and should generally see better
> > performance because of it.
> > 
> > - Applications which adapt to the network are capable of
> > running over a much wider range bandwidths and are hence
> > more useful in the Internet.
> > 
> > - Congestion control algorithms prevent the network from
> > entering Congestive Collapse. Congestive Collapse is a
> > situation where, although the network links are being
> > heavily utilized, very little useful work is being
> > done. (Think of metropolitan traffic gridlock...)
> > 
> > - The network will soon begin to require applications to
> > perform congestion control, and those applications which do
> > not perform congestion control will be harshly penalized by
> > the network (probably in the form of preferentially dropping
> > their packets during times of congestion).
> > </blockquote>
> > 
> > The last point is very important.  
> > The IETF Transport Area Working Group
> > (http://www.ietf.org/html.charters/tsvwg-charter.html) is
> > coming down **hard** on any protocol that does not specify
> > congestion control.
> > 
> > I assert that once you add in adequate congestion control
> > and real, honest-to-gosh reliability, not to mention a
> > little bit of security, your UDP protocol will be bulkier
> > and slower than TCP.  We've been working on TCP for 20+
> > years, and it's been getting smaller and faster all the
> > time.  There's not much in there that isn't needed.
> > 
> > I'm willing to believe that there are protocol geeks (term
> > of respect) out there who know more about queuing theory
> > than I do.
> > 
> > On another note, TCP is a lot easier to get through
> > firewalls, because of all of that "overhead".
> > 
> > Now, if you wanted to recommend SCTP
> > (http://www.ietf.org/rfc/rfc2960.txt), you might have a good
> > argument, as long as you first get all of the OS, firewall,
> > and router vendors to support it.  :)
> > 
> > 
> > Dave <dave at dave.tj> writes:
> > 
> > > If TCP were so quick and efficient, I wouldn't be able to write a simple
> > > (unoptimized) FTP implementation (client+server) using UDP that can outrun
> > > my UNIX command-line FTP connecting to my ftpd by 10%-30%.  I'm sure
> > > a good programmer can implement FTP over UDP even better than I did.
> > > If speed is your drug, TCP is the equivalent of a cop.
> > >
> > >  - Dave
> > >
> > >
> > > Peter Millard wrote:
> > >> 
> > >> Dave -
> > >> 
> > >> It's apparent that you have no idea about the goals and extent of TCP ...
> > >> I'd suggest you read the following links before you post any more replies:
> > >> 
> > >> http://www.ietf.org/rfc/rfc793.txt
> > >> http://www.ietf.org/rfc/rfc768.txt
> > >> http://www.ietf.org/rfc/rfc791.txt
> > >> 
> > >> pgm.
> > >> 
> > >> _______________________________________________
> > >> Standards-JIG mailing list
> > >> Standards-JIG at jabber.org
> > >> http://mailman.jabber.org/listinfo/standards-jig
> > >> 
> > >
> > > _______________________________________________
> > > Standards-JIG mailing list
> > > Standards-JIG at jabber.org
> > > http://mailman.jabber.org/listinfo/standards-jig
> > 
> > -- 
> > Joe Hildebrand
> > Chief Architect
> > Jabber, Inc.
> > http://www.jabber.com/
> > 
> > _______________________________________________
> > Standards-JIG mailing list
> > Standards-JIG at jabber.org
> > http://mailman.jabber.org/listinfo/standards-jig
> > 
> 
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