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The net.inet.tcp.inflight* sysctls are in their own, separate sysctl

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node since revision 1.196 of `src/sys/netinet/tcp_subr.c'.  Update
their description in the Handbook, but keep a reference to the old
pre-5.3-RELEASE names until we stop supporting 4.X releases (a couple
of years from now).

PR:		docs/76462
Submitted by:	Joel Dahl <joel@automatvapen.se>
This commit is contained in:
Giorgos Keramidas 2005-01-20 12:36:00 +00:00
parent eda73f8915
commit 1c87db4bc5
Notes: svn2git 2020-12-08 03:00:23 +00:00 
svn path=/head/; revision=23596
1 changed files with 18 additions and 6 deletions
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24
en_US.ISO8859-1/books/handbook/config/chapter.sgml
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@ -2171,12 +2171,12 @@ device_probe_and_attach: cbb0 attach returned 12</screen>
<indexterm>
<primary>TCP Bandwidth Delay Product Limiting</primary>
<secondary><varname>net.inet.tcp.inflight_enable</varname></secondary>
<secondary><varname>net.inet.tcp.inflight.enable</varname></secondary>
</indexterm>
<para>The TCP Bandwidth Delay Product Limiting is similar to
TCP/Vegas in NetBSD. It can be
enabled by setting <varname>net.inet.tcp.inflight_enable</varname>
enabled by setting <varname>net.inet.tcp.inflight.enable</varname>
sysctl variable to <literal>1</literal>. The system will attempt
to calculate the bandwidth delay product for each connection and
limit the amount of data queued to the network to just the amount
@ -2187,9 +2187,9 @@ device_probe_and_attach: cbb0 attach returned 12</screen>
with a high bandwidth delay product), especially if you are also
using window scaling or have configured a large send window. If
you enable this option, you should also be sure to set
<varname>net.inet.tcp.inflight_debug</varname> to
<varname>net.inet.tcp.inflight.debug</varname> to
<literal>0</literal> (disable debugging), and for production use
setting <varname>net.inet.tcp.inflight_min</varname> to at least
setting <varname>net.inet.tcp.inflight.min</varname> to at least
<literal>6144</literal> may be beneficial. However, note that
setting high minimums may effectively disable bandwidth limiting
depending on the link. The limiting feature reduces the amount of
@ -2202,7 +2202,7 @@ device_probe_and_attach: cbb0 attach returned 12</screen>
/ server side). It has no effect on data reception (downloading).
</para>
<para>Adjusting <varname>net.inet.tcp.inflight_stab</varname> is
<para>Adjusting <varname>net.inet.tcp.inflight.stab</varname> is
<emphasis>not</emphasis> recommended. This parameter defaults to
20, representing 2 maximal packets added to the bandwidth delay
product window calculation. The additional window is required to
@ -2211,9 +2211,21 @@ device_probe_and_attach: cbb0 attach returned 12</screen>
links (though still much lower than you would get without the
inflight algorithm). In such cases, you may wish to try reducing
this parameter to 15, 10, or 5; and may also have to reduce
<varname>net.inet.tcp.inflight_min</varname> (for example, to
<varname>net.inet.tcp.inflight.min</varname> (for example, to
3500) to get the desired effect. Reducing these parameters
should be done as a last resort only.</para>
<note>
<para>In 4.X and earlier releases of &os; the
<literal>inflight</literal> sysctl variables are directly under
<varname>net.inet.tcp</varname>. Their names are
(in alphabetic order):
<varname>net.inet.tcp.inflight.debug</varname>,
<varname>net.inet.tcp.inflight.enable</varname>,
<varname>net.inet.tcp.inflight.max</varname>,
<varname>net.inet.tcp.inflight.min</varname>,
<varname>net.inet.tcp.inflight.stab</varname>.</para>
</note>
</sect3>
</sect2>
</sect1>