This object is to map the IP Multimedia Subsystem (IMS)
signaling traffic to one of UMTS traffic class.
Only 'interactive' or 'background' traffic class can be
set to this object.
If the traffic class is set to 'interactive', then the
priority has to be set in cggsnUmtsQosMapImsSigTrafHandPri.
This object is deprecated as the IMS is not supported from
GGSN release 5.0 onwards.