Administer an additional SIP trunk to an existing QSIP trunk

If an additional SIP connection is used between two Communication Managers in parallel to the Q-SIP connection, you must administer a different port for the SIP connection.

Automatic Callback or Call Completion (CCBS/CCNR)

With QSIG, when a CCBS/CCNR request is initiated to a busy or free subscriber, a new TSC connection is established from the originating side. Through the TSC connection, the request is transmitted to the terminating side. The TSC is retained or released, based on the Connection Retention or Connection Released (drop-if-possible) method, and after you enter the request. To avoid TSC with longer duration, use the Connection Released method. With the Connection Retention method, the TSC is up until the CCBS/CCNR request is completed. If the Q-SIP trunk receives a CCBS/CCNR request from a transit PABX, the method chosen by the remote PBX remains unchanged. If you use the Connection Retention method, the method consumes a SIP resource until the CCBS/CCNR request is completed.

Avoid long-term Temporary Signaling Connections for Q-SIP

In Communication Manager, a Temporary Signaling Connection (TSC) is used for a QSIG call-independent (connection oriented) signaling connection. Communication Manager does not support TSC for SIP. Instead, a SIP connection with a SIP resource is established. With Q-SIP a call-independent signaling connection is also transported through a SIP resource. The TSC, which is only a short connection, consumes a SIP resource. If some features maintain a TSC for some minutes and they establish a new TSC for each feature activation, each active TSC reduces the number of available calls over the QSIP trunk. As a longer TSC consumes the SIP resources, you must be careful using features based on a call-independent signaling connection such as Call Completion and Message Waiting Indication.

Call Detail Recording (CDR) records for the QSIG trunks

The QSIG over SIP feature uses two trunks per call, but the system generates Call Detail Recording (CDR) records for the QSIG trunk. To generate the CDR records for the QSIG trunks, you must set the CDR Reports field on the SIP trunk group screen for the Q-SIP pair to n and the CDR Reports field on the QSIG trunk group screen to y.

Compatibility to ECMA-355 (3rd Edition)

Q-SIP is based on ECMA-355 (3rd Edition). Following this Q-SIP standard, Direct Media is not supported.

Inter Gateway Alternate Routing

Inter Gateway Alternate Routing (IGAR) over Q-SIP is not supported in Communication Manager 6.0 release.

Message Waiting Indication (MWI)

Depending on how Message Waiting is configured, Communication Manager sends a REL COMPLETE or a CONNECT message while answering to an incoming MWI request. To avoid TSC with longer duration, configure Communication Manager to answer with REL COMPLETE. If Communication Manager responds with a CONNECT message, the TSC could stay up for 4 hours: 15 minutes. After this time, Communication Manager releases the connection. If the QSIG part is released, the SIP trunk is also released. You can configure Communication Manager to answer with CONNECT only when the Message Center, which has initiated the MWI request, releases the call with REL COMPLETE after receiving the CONNECT message. For more information, see Configuring message waiting using a QSIG-connected messaging adjunct.

Q-SIP queueing on SIP trunk is independent of a Q-SIP call

The Q-SIP queueing on QSIG trunk feature queues calls if the QSIG trunk-group is busy. As soon as a QSIG trunk member becomes available, the call is unqueued and established automatically. The QSIG trunk is used to provide the fundamental mechanism for signaling QSIG messages over SIP.

The Q-SIP queueing on SIP trunk feature cannot work if the SIP trunk-group is busy. Because the SIP trunk is only for the tunnel establishment and provides only the transport mechanism.