[e2e] T/TCP usage

[John Kristoff]

After reviewing some of the Internet's protocol designs this afternoon,
I was making my way through T/TCP and I began to think about some of the
potential DoS vectors it could introduce.  Apparently the potential for
problems are well known.  For example:

  <http://www.cl.cam.ac.uk/users/br260/doc/ettcp.pdf>

I'm curious if T/TCP is actively in use or currently enabled by default
in any stack.  Though I suspect only the latter would be true for very
specific turnkey systems or applications.

Richard Stevens old T/TCP page indicates that at least at one time
some sites were enabling it:

  <http://www.kohala.com/start/ttcp.html>

I didn't find any evidence to indicate that anyone is using it today.
Does anyone have information regarding current use or could someone
summarize it's history?

John