SIP proprietary header fields

We can create a SIP servlet request that includes proprietary header fields. SIP proprietary header fields enable certain SIP settings to be implemented on a per message basis. SIP settings set at the SIP container level apply to all SIP messages handled by that SIP container.

To include one or more proprietary header fields in a message, set up your SIP servlet request such that it includes one or more SipServletMessage.setHeader(string_name, string value) methods. When the application calls SipServletRequest.send() to send the request, the message object that is passed to the SIP stack for transmission includes the propriety header information. The SIP stack then creates a client transaction to send out the request, and adjusts the SIP configuration settings for this specific request based on any proprietary header fields included in the message object. The stack removes the proprietary header fields before the message is sent out to the network.

Proprietary header fields used to specify timer values

The following proprietary header fields are available for specifying timer values for a specific message. The application can set multiple timer values in one message instance, but cannot specify multiple values for the same proprietary header field.

IBM-TransactionTimeout

Use this header field to specify, in milliseconds, the length of the client transaction timeout. This header is equivalent to specifying a value for timer B in INVITE client transactions, and timer F in non-INVITE client transactions.

IBM-RetransmissionInterval

Use this header field to specify, in milliseconds, the length of the request retransmission interval. This header is equivalent to specifying a value for timer A in INVITE client transactions, and timer E in non-INVITE client transactions.

IBM-RetransmissionMaxInterval

Use this header field to specify, in milliseconds, the maximum retransmission interval. This header is equivalent to specifying a value for timer T2 in non-INVITE client transactions, and timer B in INVITE client transactions.

SIP SipServletRequest and SipServletResponse classes

SIP timers settings