lcr_user.sgml

性能优秀的SIP Proxy

<!-- Module User's Guide -->

<chapter>
	<chapterinfo>
	<revhistory>
		<revision>
		<revnumber>$Revision: 1.10 $</revnumber>
		<date>$Date: 2006/04/28 09:20:28 $</date>
		</revision>
	</revhistory>
	</chapterinfo>
	<title>User's Guide</title>
	
	<section>
	<title>Overview</title>
	<para>
		Least cost routing (LCR) module implements two related capabilities:
	</para>
	<para>
		<itemizedlist>
			<listitem>
			<para>
				sequential forwarding of a request to one or more gateways
				(functions load_gws and next_gw)
			</para>
			</listitem>
			<listitem>
			<para>
				sequential forwarding to contacts if they don't share the
				the same qvalue (functions load_contacts and next_contacts).
			</para>
			</listitem>
		</itemizedlist>
	</para>
	<para>
	Gateway selection is based on caller's RPID URI (if available in
	caller's RPID AVP after authentication) or From URI and user part of
	Request-URI (telephone number).  A gateway matches a request if user
	part of Request-URI and "From" URI match the prefix and From pattern
	of the gateway.  Matching gateways are then ordered for forwarding
	purpose (1) according to longest user part match, (2) according to
	gateway's priority, and (3) randomly.
	</para>
	<para>
	Each gateway belongs to a gateway group either alone or among other
	gateways.  All gateways in a group share the same priority.
	</para>
	<para>
	Gateway and routing information is kept in two tables: gw and lcr.
	</para>
	<para>
	When a gateway is selected, the Request-URI user part is stripped by 
	the number of digits specified in the strip parameter. Subsequently,
	the Request-URI is rewritten with information from gw table:
	URI scheme, prefix, IP address, port, and transport protocol.  Valid
	URI scheme values are NULL = sip, 1 = sip and 2 = sips.  Prefix is
	appended in front of Request-URI user part. Currently valid transport
	protocol values are NULL = none, 1 = udp, 2 = tcp, and 3 = tls.
	</para>
	<para>
	Table lcr contains prefix of user part of Request-URI, From URI,
	gateway group id, and priority.  From URI can contain special
	characters % and _ matching any number of any characters and any one
	character, respectively, if db_mod parameter is set to 0.
	If db_mod parameter is set to 1, then From URI is a regular 
	expression.
	</para>
	<para>
	In addition to gw and lcr tables there is third table gw_grp that is
	used to associate names with gateway group ids.
	</para>
	</section>

	<section>
	<title>Dependencies</title>
	<section>
	<title>&ser; modules</title>
	<para>
		The following modules must be loaded before this module:
		<itemizedlist>
		<listitem>
		<para>
			<emphasis>TM module</emphasis>
		</para>
		</listitem>
		<listitem>
		<para>
			<emphasis>A database module like mysql, postgres or 
			dbtext</emphasis>.
		</para>
		</listitem>
		</itemizedlist>
	</para>
	</section>
	<section>
	<title>External libraries or applications</title>
	<para>
		The following libraries or applications must be installed before
		running &ser; with this module:
			<itemizedlist>
			<listitem>
			<para>
				<emphasis>none</emphasis>.
			</para>
			</listitem>
			</itemizedlist>
	</para>
	</section>
	</section>

	<section>
	<title>Exported Parameters</title>
	<section>
		<title><varname>db_url</varname> (string)</title>
		<para>
		&url; of the database table to be used.
		</para>
		<para>
		<emphasis>
			Default value is 
			<quote>mysql://openserro:openserro@localhost/openser</quote>.
		</emphasis>
		</para>
		<example>
		<title>Setting <varname>db_url</varname> module parameter</title>
		<programlisting format="linespecific">
...
modparam("lcr","db_url","mysql://muser:pwd@localhost/openser")
...
</programlisting>
		</example>
	</section>

<section>
		<title><varname>gw_table</varname> (string)</title>
		<para>
		Name of the table holding the gateways definitions.
		</para>
		<para>
		<emphasis>
			Default value is <quote>gw</quote>.
		</emphasis>
		</para>
		<example>
		<title>Setting <varname>gw_table</varname> module parameter</title>
		<programlisting format="linespecific">
...
modparam("lcr","gw_table","gw")
...
</programlisting>
		</example>
	</section>

<section>
		<title><varname>gw_name_column</varname> (string)</title>
		<para>
		Name of the column holding the gateway name.
		</para>
		<para>
		<emphasis>
			Default value is <quote>gw_name</quote>.
		</emphasis>
		</para>
		<example>
		<title>Setting <varname>gw_name_column</varname> module parameter</title>
		<programlisting format="linespecific">
...
modparam("lcr","gw_name_column","gw_name")
...
</programlisting>
		</example>
	</section>

<section>
		<title><varname>ip_addr_column</varname> (string)</title>
		<para>
		Name of the column holding the IP address of the gateway.
		</para>
		<para>
		<emphasis>
			Default value is <quote>ip_addr</quote>.
		</emphasis>
		</para>
		<example>
		<title>Setting <varname>ip_addr_column</varname> module parameter</title>
		<programlisting format="linespecific">
...
modparam("lcr","ip_addr_column","ip_addr")
...
</programlisting>
		</example>
	</section>

<section>
		<title><varname>port_column</varname> (string)</title>
		<para>
		Name of the column holding the port number of the gateway.
		</para>
		<para>
		<emphasis>
			Default value is <quote>port</quote>.
		</emphasis>
		</para>
		<example>
		<title>Setting <varname>port_column</varname> module parameter</title>
		<programlisting format="linespecific">
...
modparam("lcr","port_column","port")
...
</programlisting>
		</example>
	</section>

<section>
		<title><varname>uri_scheme_column</varname> (string)</title>
		<para>
		Name of the column holding the uri scheme of the gateway.
		</para>
		<para>
		<emphasis>
			Default value is <quote>uri_scheme</quote>.
		</emphasis>
		</para>
		<example>
		<title>Setting <varname>uri_scheme_column</varname> module 
		parameter</title>
		<programlisting format="linespecific">
...
modparam("lcr","uri_scheme_column","scheme")
...
</programlisting>
		</example>
	</section>

<section>
		<title><varname>transport_column</varname> (string)</title>
		<para>
		Name of the column holding the transport type to be used for 
		the gateway.
		</para>
		<para>
		<emphasis>
			Default value is <quote>transport</quote>.
		</emphasis>
		</para>
		<example>
		<title>Setting <varname>transport_column</varname> module 
		parameter</title>
		<programlisting format="linespecific">
...
modparam("lcr","transport_column","transport")
...
</programlisting>
		</example>
	</section>

<section>
		<title><varname>grp_id_column</varname> (string)</title>
		<para>
		Name of the column holding the group ID.
		</para>
		<para>
		<emphasis>
			Default value is <quote>grp_id</quote>.
		</emphasis>
		</para>
		<example>
		<title>Setting <varname>grp_id_column</varname> module parameter</title>
		<programlisting format="linespecific">
...
modparam("lcr","grp_id_column","grp_id")
...
</programlisting>
		</example>
	</section>

<section>
		<title><varname>lcr_table</varname> (string)</title>
		<para>
		Name of the table holding the LCR rules.
		</para>
		<para>
		<emphasis>
			Default value is <quote>lcr</quote>.
		</emphasis>
		</para>
		<example>
		<title>Setting <varname>lcr_table</varname> module parameter</title>
		<programlisting format="linespecific">
...
modparam("lcr","lcr_table","lcr")
...
</programlisting>
		</example>
	</section>

<section>
		<title><varname>strip_column</varname> (string)</title>
		<para>
		Name of the column holding the number of digits to strip from the RURI before applying the prefix.
		</para>
		<para>
		<emphasis>
			Default value is <quote>strip</quote>.
		</emphasis>
		</para>
		<example>
		<title>Setting <varname>strip_column</varname> module parameter</title>
		<programlisting format="linespecific">
...
modparam("lcr","strip_column","strip")
...
</programlisting>
		</example>
	</section>

<section>
		<title><varname>prefix_column</varname> (string)</title>
		<para>
		Name of the column holding the RURI(destination) prefix.
		</para>
		<para>
		<emphasis>
			Default value is <quote>prefix</quote>.
		</emphasis>
		</para>
		<example>
		<title>Setting <varname>prefix_column</varname> module parameter</title>
		<programlisting format="linespecific">
...
modparam("lcr","prefix_column","prefix")
...
</programlisting>
		</example>
	</section>

<section>
		<title><varname>from_uri_column</varname> (string)</title>
		<para>
		Name of the column holding the FROM (source) URI.
		</para>
		<para>
		<emphasis>
			Default value is <quote>from_uri</quote>.
		</emphasis>
		</para>
		<example>
		<title>Setting <varname>from_uri_column</varname> module parameter</title>
		<programlisting format="linespecific">
...
modparam("lcr","from_uri_column","from_uri")
...
</programlisting>
		</example>
	</section>

<section>
		<title><varname>priority_column</varname> (string)</title>
		<para>
		Name of the column holding the priority of the rule.
		</para>
		<para>
		<emphasis>
			Default value is <quote>priority</quote>.
		</emphasis>
		</para>
		<example>
		<title>Setting <varname>priority_column</varname> module parameter
			</title>
		<programlisting format="linespecific">
...
modparam("lcr","priority_column","priority")
...
</programlisting>
		</example>
	</section>

<section>
		<title><varname>gw_uri_avp</varname> (string)</title>
		<para>
   Overrides the name of the AVP containing URI scheme, host, port, and
   transport of a gateway.  If the string name of the AVP contains only
   digits, the name of the AVP is integer value of the string.
		</para>
		<para>
		<emphasis>
			Default value is <quote>1400</quote>.
		</emphasis>
		</para>
		<example>
		<title>Setting <varname>gw_uri_avp</varname> module parameter</title>
		<programlisting format="linespecific">
...
modparam("lcr","gw_uri_avp","1400")
...
</programlisting>
		</example>
	</section>
<section>
		<title><varname>ruri_user_avp</varname> (string)</title>
		<para>
   Overrides the name of the AVP containing user part of Request-URI
   after the first next_gw() call.  If the string
   name of the AVP contains only digits, the name of the AVP is integer
   value of the string.
		</para>
		<para>
		<emphasis>
			Default value is <quote>1402</quote>.
		</emphasis>
		</para>
		<example>
		<title>Setting <varname>ruri_user_avp</varname> module parameter</title>
		<programlisting format="linespecific">
...
modparam("lcr","ruri_user_avp","500")
...
</programlisting>
		</example>
	</section>

<section>
		<title><varname>contact_avp</varname> (string)</title>
		<para>
		Overrides the name of the AVP containing the contact. If the string