View source for SIP Attended Call Transfer In Cluster


This page documents how to configure Yate to handle a SIP attended call transfer for an unknown call leg in the cluster node.<br>
If the SIP module can't find the call in its list, it will try to route and execute the transfer request.

Below are the steps to follow.
<!--* Enable REFER method handler in the [[SIP_channel_module|SIP module]]
* Enable and configure [[clustering]]
* Enable and configure the line tracker
* Route transfer requests using the line tracker
* Configure [[CDR Build Module|cdrbuild]] to copy extra parameter(s)-->

===Enable REFER method handler in the [[SIP Configuration File#Configuration|SIP module]]===

ysipchan.conf
 
 [general]
 ;Allow handling the REFER message to perform transfers
 transfer=yes

=== Enable and configure [[clustering]] ===

'''REMEMBER: It is mandatory to choose node names that can be easily resolved to an IP address.<br>
The SIP call to another cluster will fail if its name can't be resolved.'''<br>
See also [[Node Name]] and [[clustering]].

'''Set node name'''
 
yate.conf
 
 [general]
 ;Name of this node in a cluster
 nodename=somehost

=== Enable and configure the clustering module===
 
clustering.conf
 
 [general]
 ;Regular expression describing node name match rules
 regexp=^[[:alnum:].-]\+$
 ;Template for forwarding the call to target node
 callto=sip/sip:cluster/${called}@\0

=== Enable and configure the line tracker ===

The line tracker is used to maintain the list of call legs in the database.<br>
The example below assumes the existence of a 'cluster' account in a database module containing a 'lines' table with the following text columns: 'nodeprefix','chan','callid','nodename'. The database can be configured in [[Modules#Database_Drivers| mysqldb.conf]] or [[Modules#Database_Drivers|pgsqldb.conf]]<br>
See also [[register]].


register.conf
 
 [general]
 ;Activate line status tracking on "call.cdr"
 linetracker=yes
 
 [linetracker]
 ; Queries for the line usage tracker
 account=cluster
 initquery=DELETE FROM lines WHERE nodename='${nodename}'
 cdr_initialize=INSERT INTO lines(nodeprefix,chan,callid,nodename)\
 VALUES('${nodeprefix}', '${chan}', '${callid}', '${nodename}')
 cdr_finalize=DELETE FROM lines WHERE nodeprefix='${nodeprefix}' AND chan='${chan}'
 cdr_update=UPDATE lines SET callid='${callid}' WHERE nodeprefix='${nodeprefix}' AND chan='${chan}'

===Route transfer requests using the line tracker===

The example below returns a cluster pickup target. 

register.conf
 
 [general]
 ;Activate handler on the "call.route" message
 call.route=yes
 
 [call.route]
 ; Query and result name for the routing message
 account=cluster
 query=SELECT nodeprefix || 'pickup/' || chan AS location FROM routes WHERE callid='${callid}' AND '${reason}'='transfer'
 result=location

===Configure [[CDR Build Module|cdrbuild]] to copy extra parameter(s)===

We need the [[CDR Build Module|cdrbuild]] module to update and forward the '''callid''' parameter.<br>
The '''callid''' parameter is added by the [[SIP_Configuration_File#Configuration|SIP module]].<br>
It is built from SIP dialog data ('Call-ID', 'From' tag, 'To' tag).<br>

cdrbuild.conf
 
 [parameters]
 ;added parameter '''callid''' to be monitorized, will appear in "call.cdr"
 callid=true

'''See also'''

* [[Register]]
* [[Clustering]]
* [[CDR Build Module]]
* [[SIP Configuration File]]
* [[Telephony]]