K 10
svn:author
V 8
lstewart
K 8
svn:date
V 27
2011-05-28T08:24:22.530455Z
K 7
svn:log
V 697
MFC 217806:

Import the ERTT (Enhanced Round Trip Time) Khelp module. ERTT uses the
Khelp/Hhook KPIs to hook into the TCP stack and maintain a per-connection, low
noise estimate of the instantaneous RTT. ERTT's implementation is robust even in
the face of delayed acknowledgements and/or TSO being in use for a connection.

A high quality, low noise RTT estimate is a requirement for applications such as
delay-based congestion control, for which we will be importing some algorithm
implementations shortly.

In collaboration with:	David Hayes <dahayes at swin edu au> and
				Grenville Armitage <garmitage at swin edu au>
Sponsored by:	FreeBSD Foundation
Reviewed by:	bz and others along the way

END