Commit e738ffc4 authored by Francis Dupont's avatar Francis Dupont
Browse files

[295-min-max-lease-time-configuration-options] Updated documentation

parent 7a05fd87
......@@ -229,15 +229,27 @@ use it for 4000 seconds. (Note that integer numbers are specified as is,
without any quotes around them.) <command>renew-timer</command> and
<command>rebind-timer</command> are values (also in seconds) that
define T1 and T2 timers that govern when the client will begin the renewal and
rebind procedures. <note>Both <command>renew-timer</command> and
<command>rebind-timer</command> are optional. The server will only send
rebind-timer to the client, via DHCPv4 option code 59, if it is less than
valid-lifetime; and it will only send renew-timer, via DHCPv4 option code 58,
if it is less than rebind-timer (or valid-lifetime if rebind-timer was not
specified). In their absence, the client should select values for T1 and T2
timers according to <link xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="http://tools.ietf.org/html/rfc2131">RFC 2131</link>.
See section <xref linkend="dhcp4-t1-t2-times"/> for more details on
rebind procedures.
<note>From Kea 1.6.0 the lease valid lifetime is extended from a
single value to a triplet with minimum, default and maximum values using
<command>min-valid-lifetime</command>, <command>valid-lifetime</command> and
<command>max-valid-lifetime</command>. When the client does not specify
a lifetime the default value is used, when it specifies using a DHCP option
code 51 this value is used if it is not lesser than the minimum (in this case
the minimum is returned) or greater than the maximum (in this case the
maximum is used).</note>
<note>Both <command>renew-timer</command>
and <command>rebind-timer</command> are optional. The server will only
send rebind-timer to the client, via DHCPv4 option code 59, if it is
less than lease valid lifetime; and it will only send renew-timer, via
DHCPv4 option code 58, if it is less than rebind-timer (or lease valid
lifetime if rebind-timer was not specified). In their absence, the
client should select values for T1 and T2 timers according
to <link xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="http://tools.ietf.org/html/rfc2131">RFC 2131</link>. See
section <xref linkend="dhcp4-t1-t2-times"/> for more details on
generating T1 and T2.</note></para>
<para>The <command>interfaces-config</command> map specifies the server
......
......@@ -2046,6 +2046,7 @@ should include options from the new option space:
<section xml:id="dhcp6-t1-t2-times">
<title>Controlling the Values Sent for T1 and T2 Times</title>
<para>
According to <link xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="http://tools.ietf.org/html/rfc8415">RFC 8415, section 21.4</link>,
the recommended T1 and T2 values are 50% and 80%
......@@ -2054,7 +2055,41 @@ should include options from the new option space:
percentages of the preferred lease time. The server's behavior is governed
by combination of configuration parameters, two of which have already been
mentioned.
<para>
</para><para>
From Kea 1.6.0 lease preferred and valid lifetime are extended from
single values to triplets with minimum, default and maximum values using:
<itemizedlist>
<listitem>
<simpara><command>min-preferred-lifetime</command> - specifies the minimal preferred lifetime (optional).
</simpara>
</listitem>
<listitem>
<simpara><command>preferred-lifetime</command> - specifies the default preferred lifetime.
</simpara>
</listitem>
<listitem>
<simpara><command>max-preferred-lifetime</command> - specifies the maximal preferred lifetime (optional).
</simpara>
</listitem>
<listitem>
<simpara><command>min-valid-lifetime</command> - specifies the minimal valid lifetime (optional).
</simpara>
</listitem>
<listitem>
<simpara><command>valid-lifetime</command> - specifies the default valid lifetime.
</simpara>
</listitem>
<listitem>
<simpara><command>max-valid-lifetime</command> - specifies the maximal valid lifetime (optional).
</simpara>
</listitem>
</itemizedlist>
When the client does not specify lifetimes the default is used. When
it specifies a lifetime using IAADDR or IAPREFIX sub option with not
zero values these values are used when they are between configured
minimal (lower values are round up) and maximal (larger values are
round down) bounds.
</para><para>
To send specific, fixed values use the following two parameters:
<itemizedlist>
<listitem>
......
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