Call Variables

A call variable stores specific information of a SIP message on a per call basis and changes when a new call is made (i.e., stored only throughout the lifetime of a specific call). The stored information can be, for example, the value of the SIP Contact header.

Local variables can be used per call: src (source) or dst (destination) references (see note below) which can be stored in the call leg.

Syntax:

var.call.src|dst.<Variable Name>

where:

■

src denotes the call source variable.

■

dst denotes the call destination variable.

■

<Variable Name> specifies the name of the variable. You can also use hard-coded variable names for the following functionality:

●

Retrieving values from SIP headers  for specific CDR fields when customizing the CDR format (see Call Variable for Obtaining CDR Field Value from SIP Header).

●

Playing a background tone (defined in the PRT file) to the call parties in an SBC call (see Call Variable for Playing Background Tone).

●

Defining maximum call duration (see Call Variable for Maximum Call Duration).

For example:

1.

Store a value in a call variable (store the subject URI parameter value of the To header):

MessageManipulations 0 = 0, Invite.Request, , var.call.dst.My-Call, 2, header.to.url.param.subject, 0;

2.

Use the stored value (allocate a Subject header for the 200 OK response for the same call and assign it the stored value):

MessageManipulations 0 = 0, Invite.response.200, , header.subject, 0, var.call.dst.My-Call, 0;

The following table provides additional configuration examples of using call variables in Message Manipulation rules.

Examples of Call Variables

Message Type	Condition	Action Subject	Action Type	Action Value
invite	param.message.sdp.rtpmode=='sendrecv'	Var.Call.Src.My-Call	Modify	'1'
invite .response.200	var.call.dst.My-Call=='1'	Param.Message.Sdp.rtpmode	Modify	'sendonly'