d/freebsd-nq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Mdoc markup and style cleanup.

Browse Source
This commit is contained in:
Christian Brueffer 2015-01-12 10:40:28 +00:00
parent 06143100da
commit cb41a56d27
1 changed files with 14 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
share/man/man4/cc_dctcp.4
View File

@ -40,18 +40,23 @@ throughput and minimise latency in data center networks by utilising the
proportion of Explicit Congestion Notification (ECN) marks received from capable
hardware as a congestion signal.
.Pp
DCTCP uses fraction of ECN marked packets to update congestion window. The
window reduction ratio is always <= 1/2. Only when all of the packets are
DCTCP uses fraction of ECN marked packets to update congestion window.
The window reduction ratio is always <= 1/2.
Only when all of the packets are
marked, congestion window is halved.
.Pp
In order to keep the accuracy of the ECN marked fraction, a DCTCP receiver
mirrors back incoming (or missing) CE marks by setting (or clearing) ECE marks.
This feedback methodology is also adopted when the receiver uses delayed ACK.
.Pp
FreeBSD DCTCP implementation includes two minor modifications for the one-sided
deployment. Considering the situation that DCTCP is used as sender and classic
The
.Fx
DCTCP implementation includes two minor modifications for the one-sided
deployment.
Considering the situation that DCTCP is used as sender and classic
ECN is used as receiver, DCTCP sets the CWR flag as the reaction to the ECE
flag. In addition, when classic ECN is used as sender and DCTCP is used as
flag.
In addition, when classic ECN is used as sender and DCTCP is used as
receiver, DCTCP avoids to mirror back ACKs only when the CWR flag is
set in the incoming packet.
.Pp
@ -75,6 +80,7 @@ Default is 16.
.It Va slowstart
A trigger to halve congestion window after slow start.
Default does nothing to halve window.
.El
.Sh SEE ALSO
.Xr cc_chd 4 ,
.Xr cc_cubic 4 ,
@ -120,8 +126,8 @@ University, Japan.
The
.Nm
congestion control module and this manual page were written by
.An Midori Kato katoon@sfc.wide.ad.jp
.An Midori Kato Mt katoon@sfc.wide.ad.jp
and
.An Lars Eggert lars@netapp.com
.An Lars Eggert Mt lars@netapp.com
with help and modifications from
.An Hiren Panchasara hiren@FreeBSD.org
.An Hiren Panchasara Mt hiren@FreeBSD.org