[e2e] Can we revive T/TCP ? => persistent connections

Jim Gettys jg at freedesktop.org
Mon Dec 26 14:24:12 PST 2005

On Mon, 2005-12-26 at 16:10 -0500, David Andersen wrote:

> > I heard the term "connection caching" before, and followed it, which
> > led to a few papers on the subject and problems with this type of
> > caching, but no standards. It doesn't seem to be an easy issue, but
> > it looks like it's solvable. If I'm right and common web servers don't
> > implement this (one could of course carry out a larger measurement
> > study for this... perhaps it has already been done), wouldn't an
> > Informational RFC which provides an overview of connection caching
> > methods and suggests an implementation do the trick?
> I believe you're mistaken.  Most web servers support it.  It's part  
> of the HTTP 1.1 spec, and has been around literally for years.
> >
> > I'd be thankful for some pointers to the key papers about connection
> > caching - e.g., where was it introduced?
> Proposed:  1995 sigcomm, Mogul, "The Case for Persistent-Connection  
> HTTP".  Dig around in some of his other papers, you'll get a good  
> feel for what's going on.
> HTTP 1.1 spec.  Persistent is the default.
> HTTP 1.0 hack, the:
> connection: keep-alive
> header.
>    -d

Web servers have supported persistent connections for a very long time
now, well before HTTP/1.1 was completed.  All the significant servers
do, and have, for many years.

What their policy is about closing the connections may vary between
implementation, configuration and load.

http://www.w3.org/Protocols/HTTP/Performance/Pipeline presents a lot of
data on HTTP/1.1 performance.

				Jim Gettys
				HTTP/1.1 editor.

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