/// <summary>
/// This method is called when INVITE 2xx retransmit timer triggered.
/// </summary>
/// <param name="sender">Sender.</param>
/// <param name="e">Event data.</param>
private void m_pTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
/* RFC 3261 13.3.1.4.
* Once the response has been constructed, it is passed to the INVITE
* server transaction. Note, however, that the INVITE server
* transaction will be destroyed as soon as it receives this final
* response and passes it to the transport. Therefore, it is necessary
* to periodically pass the response directly to the transport until the
* ACK arrives. The 2xx response is passed to the transport with an
* interval that starts at T1 seconds and doubles for each
* retransmission until it reaches T2 seconds (T1 and T2 are defined in
* Section 17). Response retransmissions cease when an ACK request for
* the response is received. This is independent of whatever transport
* protocols are used to send the response.
*
* Since 2xx is retransmitted end-to-end, there may be hops between
* UAS and UAC that are UDP. To ensure reliable delivery across
* these hops, the response is retransmitted periodically even if the
* transport at the UAS is reliable.
*
* If the server retransmits the 2xx response for 64*T1 seconds without
* receiving an ACK, the dialog is confirmed, but the session SHOULD be
* terminated. This is accomplished with a BYE, as described in Section
* 15.
*/
lock (m_pLock){
if (m_StartTime.AddMilliseconds(64 * SIP_TimerConstants.T1) < DateTime.Now)
{
// Log
if (m_pDialog.Stack.Logger != null)
{
m_pDialog.Stack.Logger.AddText("Dialog [id='" + m_pDialog.ID + "'] ACK was not received for (re-)INVITE, terminating INVITE session.");
}
m_pDialog.Terminate("Dialog Error: ACK was not received for (re-)INVITE.", true);
Dispose();
}
else
{
// Retransmit response.
try{
m_pDialog.Flow.Send(m_pResponse);
// Log
if (m_pDialog.Stack.Logger != null)
{
m_pDialog.Stack.Logger.AddText("Dialog [id='" + m_pDialog.ID + "';statusCode=" + m_pResponse.StatusCode + "] UAS 2xx response retransmited");
}
}
catch (Exception x) {
// Log
if (m_pDialog.Stack.Logger != null)
{
m_pDialog.Stack.Logger.AddText("Dialog [id='" + m_pDialog.ID + "'] UAS 2xx response retransmission failed: " + x.Message);
}
}
m_pTimer.Interval = Math.Min(m_pTimer.Interval * 2, SIP_TimerConstants.T2);
m_pTimer.Enabled = true;
}
}
}
