[Users] Duplicate INVITEs

We're seeing sporadic situations where fones a) send an INVITE b) ignore the 100-Trying response, and instead c) send another INVITE with the same sequence number. The question is, What should happen here? Currently, we send back a 500 response (server error). Is this correct? (i think not, cause it invariably causes the fone to go fast busy). Is this some other response that should occur? poring over 3261 resulted in a headache, and no additional clarity... -- ******************************************* Mahesh Paolini-Subramanya (703) 386-1500 x9100 CTO mahesh(a)aptela.com Aptela, Inc. http://www.aptela.com "Aptela: How Business Answers The Call" *******************************************