Looking specifically at an IS-826 deployment using ANSI TCAP, what should a CONNFAIL use as the invoke correlation?

I believe that the message flow in a compliant environment will look like this, somewhat abstracted:

• ANLYZD tid anlyzd-tid cid anlyzd-cid
• CONNRES tid connres-tid-anlzyd-tid cid connres-cid-anlyzd-cid
• CCDIR tid ccdir-tid cid ccidr-cid
• ccdir_rr tid ccdir-tid cid ccdir-cid (try saying that three times fast)
• RESETTIMER tid connres-tid-anlzyd-tid cid connres-cid+1-anlyzd-cid
• ...
• CONNFAIL tid anlyzd-tid-connres-tid cid anlyzd-cid+1-last-reset-timer-cid
• anlyzd_rr tid anlyzd-tid cid anlyzd-cid

I think that this implies a CONNRES dialogue needs to remain available until either:

• a CONNFAIL is received on it
• a DISCONNRES is sent on it
• (optionally) CCDIR failure tears the call down

This doesn't dovetail very well with the optionality of CCDIRs - how do you avoid potential call leaks without timers on an invoking dialogue? Do you rely on the MSC having a timer fire off the ANLYZD? Wouldn't the CONNRES force that to be elided?